Lagged strain of laminates in RC beams strengthened with fiber-reinforced polymer

Figure 3CHO-SEAL 1285 and CHO-SIL 1485Sheet Stock Compression-DeflectionCompression-Deflectionspecial shapes.Conductive ElastomersCompression-DeflectionWhile standard test procedures have been established for measuring the deflection of elastomers under compressive loads, the practical use of such data is to provide a qualitative comparison of thedeformability of different elastomeric materials when in the particular configuration of the test sample.Solid (non-foam) elastomers are essentially incompressible materials;i.e., they cannot be squeezed into a smaller volume. When a solid elas-tomer is subject to a compressive load, it yields by deformation of the part as a whole. Because of this behavior, the actual deflection of a gasket under a compressive load depends upon the size and shape of the gasket as well as on its modulus and the magnitude of the load.The design of a seal should be such that it will be subjected to the minimum squeeze sufficient toprovide the required mechanical and electrical performance. The designed deflection of conductive elastomer gaskets should never exceed the maximum deflection limits shown in Table 1.There is an approximate relation-ship between the force required to deflect a pure elastomer a given amount, and the hardness of the elastomer. In general, the harder the elastomer, the greater the force required. In the case of Chomerics’metal particle-filled elastomers, this relationship is much less definite,and in some instances, these materials demonstrate deflection/hardness and deflection/thickness behavior contrary to that which would be anticipated for conventional rubber compounds.The inclusion of metal particles in the elastomer results in a mechanically structured material. This mechanical structure has a marked effect on the deflection of the elastomer under compressive loads, and in some instances, harder materials deflect more than softer materials.Compressive load-deflection data for many popular conductiveelastomer materials and shapes are given in Figures 1-25. (For “linecontact” gaskets, it is more convenient to express the load in terms of pounds per linear inch instead of pounds per square inch).For compression-deflection data on other Chomerics gaskets, contact our Applications Engineering Department.Compression-DeflectionCompression-DeflectionCONTENTS:Compression-Deflection 80Stress Relaxation 83Compression Set 83Shielding Effectiveness 83EMP Survivability 84Vibration Resistance 84Heat Aging 85Outgassing85Volume Resistivity Measurement86Figure 80.125 in. (3.18 mm) Dia. O-Strip Compression-DeflectionDeflection,%Compression-DeflectionCompression-DeflectionL o a d , l b ./i n c hDeflection, %Figure 210.156 in. (3.96 mm) High Hollow D-Strip Compression-DeflectionL o a d , l b ./i n c hDeflection, %Figure 220.312 in. (7.92 mm) High Hollow D-Strip Compression-DeflectionFigure 200.250 in. (6.35 mm) Dia. Hollow O-Strip Compression-DeflectionL o a d , l b ./i n c hDeflection, %L o a d , l b ./i n c hDeflection, %Figure 230.250 in. (6.35 mm) Dia. Hollow P-Strip Compression-DeflectionFigure 240.360 in. (9.14 mm) Dia. Hollow P-Strip Compression-DeflectionL o a d , l b ./i n c hDeflection, %L o a d , l b ./i n c hDeflection,%Figure 190.156 in. (3.96 mm) Dia. Hollow O-Strip Compression-DeflectionL o a d , l b ./i n c hDeflection, %Figure 170.250 in. (6.35 mm) Wide Rectangular Strip Compression-Deflection0.40.81.20.20.61.0C o m p r e s s i o n F o r c e (l b /i n )00.5 1.50.10.2Deflection (inch)1356P/N 10-09-W864-XXXXFigure 250.410 in. (10.41 mm) High V-Strip Compression-DeflectionStress RelaxationAs important as Compression Set and Compression-Deflection, is the Stress Relaxation characteristic of a gasket.If a rubber is subject to a com-pressive load, it will deflect. There is a stress/strain relationship, which for rubbers is generally non-linear except for very small deflections.After the load is applied, a stress decay occurs within the polymer resulting from the internal rearrange-ment of the molecular structure. An approximate rule is that the relaxed stress for cured silicone will finally settle at 70 to 75 percent of the initial stress.There are two ways in which a rubber gasket can be loaded to a desired value. One way is to load it to a point, let it relax, and reapply the load to restore the original stress. The next time it will relax, but not so much.If this is repeated a sufficient number of times, the correct static load on the gasket will reach equilibrium.A more practical way to reach the design value of stress is to load the gasket to 125 percent of its final design value, so that after the relax-ation process is completed the gasket will settle to 100 percent of the design load. This is very reproducible.Figure 26shows a typical stress relaxation curve for Chomerics’conductive elastomers.Compression SetWhen any rubber is deformedfor a period of time, some of the defor-mation is retained permanently even after the load is removed. The amount of permanent deformation, asmeasured by ASTM D395, is termed “Compression Set.” Compression set is measured under conditions of constant deflection (ASTM D395Method B) and is normally expressed as a percentage of the initialdeflection, not as a percentage of the initial height.For gaskets that are used once, or where the gasket/flange periphery relationship is constant (such as a door gasket), compression set is of minor significance if the original load condition and the service temperature are within the design limitations of the gasket material.For gaskets that are randomlyreseated one or more times in normal service life, it is important that the maximum change in gasket thickness does not exceed twice the maximum mismatch between the opposing mating surfaces.Shielding EffectivenessMost shielding effectiveness data given in Table 3 of the Conductive Elastomer section (pages 32-34) is based on a MIL-G-83528B testmethod, with a 24 in. x 24 in. aperture in a rigid enclosure wall and about 100 psi on the gasket. It is a valid and useful way of comparing variousgasket materials, but does not reflect the shielding effectiveness one can expect at seams of typical enclosures.CHO-TM-TP08 is a modified version of the MIL test that provides typical values achieved in actual applications.Since many factors will affect the actual shielding effectiveness of anenclosure seam (flange design,stiffness, flatness, surface resistivity,fastener spacing, enclosuredimensions, closure force, etc.), the only way to determine shielding effectiveness for real enclosures is to test them.Figures 28and 29provide dataon shielding effectiveness for actualFigure 27Formula for Calculation of Compression Setenclosures. The data in Figure 28shows the difference in attenuation between a shelter door closed with no gasket and the same door closed against a CHO-SEAL 1215 hollow D-strip gasket. Instead of single data points at each frequency tested, a range of data is shown for eachfrequency, representing the worst and best readings measured at many points around the door. Figure 29 shows the effects of closure force on shielding effectiveness of an enclosure tested at high frequencies (1-40 GHz) using CHO-SEAL 1215 solid D-strip gaskets.In order to establish reasonable upper limits on gasket resistivity, it is necessary to understand the rela-tionship between flange interface resistance and EMI leakage through the flange. Figure 30presents this relationship for an aluminum enclosure 3 in. x 3 in. x 4 in. deep, measured at 700 MHz. Die-cut gaskets 0.144 in.wide by 0.062 in. thick, in a wide range of resistivities, were clamped between the gold-plated flanges of thisenclosure. Simultaneous measure-ments of flange interface resistance (all attributable to the gaskets) versus RF leakage through the seamproduced a classic S-shaped curve.For the gasket configuration used in this test, the dramatic change in shielding effectiveness occursbetween gasket volume resistivities of 0.01 and 0.4 ohm-cm. Since real enclosures do not have gold-plated flanges, but rather have surfacefinishes (such as MIL-C-5541 Class 3chromate conversion coatings) which also increase in resistance over time, it is recommended that gasket volume resistivity be specified at 0.01 ohm-cm max. for the life of the equipment.Frequency, HzA t t e n u a t i o n (dB )Figure 28Shielding Effectiveness of a Shelter Door Gasket (14 kHz to 10 GHz)kA/inch of gasket (peak-to-peak).Pure silver (1224) and silver-plated-aluminum filled (1285) gaskets have less current carrying capability than silver-plated-copper materials, but are generally acceptable for EMP hardened systems (depending on specific EMP threat levels, gasket cross section dimensions, etc.).Vibration ResistanceCertain conductive elastomers are electrically stable during aircraft-level vibration environments, while others are not. The key factor which deter-mines vibration resistance is theshape and surface texture of the filler particles. Smooth, spherical fillers (such as those used in silver-plated-Figure 32Scanning Electron Microscopy Illustrates EMP Damage Mechanism for Silver/Glass ElastomersL e a k a g e (d B )Vibration (g)Figure 33Effects of Vibration on Shielding Effectiveness of Conductive Elastomer GasketsEMP SurvivabilityIn order for an enclosure to continue providing EMI isolationduring and after an EMP environment,the conductive gaskets at joints and seams must be capable of carrying EMP-induced current pulses without losing their conductivity. Figure 31shows the EMP current response of various types of conductive elastomer gaskets. Note that gaskets based on silver-plated-glass fillers (1350)become nonconductive at low levels of EMP current, and should therefore not be used when EMP is a design consideration. Figure 32is an electron microscope photo which clearly shows the damage mechanism.Silver-plated-copper filled (1215)gaskets have the highest resistance to EMP type currents, showing no loss of conductivity even at 2.50102030405060Shielding Degradation, dBIn t e r f a c e R e s i s t a n c e , m i l l i o h m sFigure 30Interface Resistance vs. Shielding Degradation at a Flange Jointglass materials) tend to move apart during vibration, leading to dramatic increases in resistance and loss of shielding effectiveness (although they normally recover their initial properties after the vibration has ended). Rough, less spherical particles resist vibration with very little electrical degradation. Figure 33shows the effects of vibration on three types of conductive gaskets.Although Chomerics’ silver-plated-copper filled 1215 gasket, with rough,irregular particle agglomerations,exhibits excellent stability during vibration, users of conductive elastomers should be aware that smooth, spherical silver-plated-copper fillers can be almost asunstable as silver-plated-glass fillers.Frequency, GHzA t t e n u a t i o n (dB )Figure 29Effect of Closure Force on Shielding Effectiveness (1 GHz to 40 GHz)Heat AgingThe primary aging mechanism which affects electrical stability of conductive elastomers is the oxidation of filler particles. Formaterials based on pure silver fillers,particle oxidation is not generally a problem because the oxide of silver is relatively soft and reasonably conductive. If the filler particles are non-noble (such as copper, nickel,aluminum, etc.) they will oxidize readily over time and become nonconductive. Even silver-plated base metal powders, such as silver-V o l u m e R e s i s t i v i t y (o h m -c m )Hours at 150°C (Solid Line)Hours at 125°C (Dotted Line)Figure 34Typical heat aging characteristics of Chomerics’ plated-powder-filled conductiveelastomers. Flanged 1000-hr test recommended for qualification. Unflanged 48-hr. test recommended for QC acceptance.plated-copper or silver-plated-aluminum will become non-conductive over time if the plating is not done properly (or if other processingvariables are not properly controlled).These are generally batch control problems, with each batch being potentially good or bad.The most reliable method of predicting whether a batch will be electrically stable is to promote the rate at which poorly plated or processed particles will oxidize, by heat aging in an air circulating oven.For qualification, 1000 hours (42 days)at maximum rated use temperature (with the gasket sample deflected 7-10% between flanges) is the recommended heat aging test for accelerating the effects of long-term aging at normal ambient tempera-tures. A quicker heat aging test,which correlates well with the 1000hour test and is useful for QC acceptance testing, involves a 48hour/150°C oven bake with thegasket sample on an open wire-grid tray (rather than being clamped between flanges). Figure 34shows typical data for volume resistivity versus time for each of these tests.Note:It is essential that no source of free sulfur be placed in the aging oven, as it will cause the material to degrade electrically and mask any oxidation aging tendencies. Common sources of sulfur are neoprenes,most cardboards and other paper products.OutgassingMany spacecraft specifications require that nonmetallic components be virtually free of volatile residues which might outgas in the hard vacuum environment of space. The standard test method for determining outgassing behavior is ASTM E595-93, which provides for measurement of total mass loss (TML) and collected volatile condensable materials (CVCM) in a vacuum environment. Data for a number of Chomerics conductive elastomers,based on ASTM E595-93 testing done by NASA Goddard SpaceflightCenter, is presented in Table 2. The normal specification limits or guide-lines on outgassing for NASA applications are 1% TML max.,and 0.1% CVCM max.。

Influence of formwork surface on the orientation of steel fibres within self-compacting concrete and on the mechanical properties of cast structuralelementsOldrˇich Švec a ,⇑,Giedrius Z ˇirgulis b ,John E.Bolander c ,Henrik Stang a aDepartment of Civil Engineering,Technical University of Denmark,2800Kgs.Lyngby,DenmarkbDepartment of Structural Engineering,Norwegian University of Science and Technology,7491Trondheim,Norway cDepartment of Civil and Environmental Engineering,University of California,Davis,CA 95616,USAa r t i c l e i n f o Article history:Received 26April 2013Received in revised form 29September 2013Accepted 5December 2013Available online 16December 2013Keywords:Fibre reinforced self-compacting concrete Fibre orientationComputed tomography Numerical simulation Fracturea b s t r a c tThe influences of formwork surface on the final orientation of steel fibres immersed in self-compacting concrete and on the resulting mechanical response of the cast structural elements are investigated.Experimental observations of fibre orientation within cast slabs,obtained via computed tomography,indicate that fibres tend to orient according to the flow patterns during casting,but such tendencies are suppressed near rough formwork surfaces.Fibre orientation,in turn,affects the mechanical proper-ties of the concrete as demonstrated by the load testing of beams extracted from the cast slabs.These processes and results are simulated using a computational fluid dynamics model of the casting process,in tandem with a lattice model of the fracture of the beam specimens.The computational fluid dynamics model determines the coordinates of each fibre within the concrete,which serve as input to the lattice model.Through comparisons with the experimental data,it is shown that these simulations correctly predict the phenomena of interest.We conclude the paper by highlighting a relationship between the number and orientation of the immersed steel fibres crossing the fracture plane and the mechanical response of the structural elements.Ó2013Elsevier Ltd.All rights reserved.1.IntroductionA growing portion of civil structures is nowadays constructed of self-compacting concrete.Contrary to ordinary concrete,self-com-pacting concrete flows and fills the formwork without any need of vibration or other type of agitation.Various forms of steel rein-forcement,such as reinforcement bars,are typically used to im-prove the behaviour of concrete loaded in tension.It might be advantageous to replace the traditional reinforcement bars by steel fibres to achieve a simple execution of the structure,while improv-ing tensile properties of the concrete.Orientation of immersed steel fibres evolve in response to the flow of the self-compacting concrete within the formwork [1,2].In particular,fibre orientations are affected by shear flow of the material and interactions with the formwork boundaries [3].The fibre orientation and thus properties of the structural elements can be then heavily dependent on the material rheology and the methods of element casting [1,4].Concrete is a multiphase material consisting of cement paste,fine and coarse aggregates,and possibly fibres.Due to the geomet-rical constraint imposed by a solid boundary on particle packing near the boundary,the distribution of immersed particles (aggre-gates,fibres,etc.)in that region becomes non-uniform,which re-sults in the so-called wall effect (Fig.1a).The wall effect thus expresses the fact that the macroscopic properties of the fluid (density,viscosity,etc.)in the bulk of the material and at the boundary layers are different.Fig.1a ,as an illustrative example,depicts composition of four different layers of flowing concrete near an oiled formwork surface.The four layers represent the oil layer,layer with fines,layer with coarser aggregates and the bulk layer.The presented layered struc-ture is an illustrative and by no means fully accurate example of the consequence of the aforementioned wall effect.Fig.1b illus-trates a velocity profile of the cross-section of the flowing concrete.The velocity profile depends on shear rates of the four individuallayers,_c1À4.It is likely that the velocity profile in the vicinity of the formwork has a direct impact on the resulting orientation of the immersed steel fibres and consequently on the resulting mechanical response of the material.The wall effect,together with various types of formwork char-acterised by different roughness and treatment,contribute to uncertainties in the behaviour of structures made of fibre rein-forced self-compacting concrete.Especially for thin elements,the flow of the material and consequently the mechanical response0958-9465/$-see front matter Ó2013Elsevier Ltd.All rights reserved./10.1016/j.cemconcomp.2013.12.002Corresponding author.E-mail address:oldrich.svec@ (O.Švec).of the elements is significantly influenced by the formwork–fluid interaction.In the field of fibre reinforced self-compacting concrete,several authors discuss the influence of casting process on the orientation of steel fibres [3,5–7].Others study the impact of fibre orientation on the mechanical response of the structural elements [1,8–10].Jacobsen et al.[11]addresses the impact of the formwork surface on the pumpability of an ordinary concrete.The presented paper merges all the problems into one by study-ing the influence of the formwork surface on the flow pattern of steel fibre reinforced self-compacting concrete close to thework.The paper further studies the influence of the final tion of steel fibres on the resulting mechanical properties of material.The study is carried out through the combined use physical experiments and numerical modelling.The study was performed by means of tomographic imaging of specimens cast with fibre reinforced self-compacting and by means of three-and four-point bending tests of cut from the slabs.The numerical study was conducted by of two distinct numerical simulations developed by the (1)a computational fluid dynamics based procedure to simulatebre movement during the casting process,including interactions at the formwork boundaries and (2)a lattice model material elasticity and fracture,including the explicit tion of individual fibres within the specimen volumes.Fibre dinates determined through the computational fluid based simulation served as direct input to the lattice of the flexural test specimens.Materials and methods of the presented study are fully de-scribed in Section 2.The casting process and the data analysis pro-cess of the experimental study are explained in Section 2.1.The two distinct numerical simulations are introduced in Section 2.2.Section 3presents all the experimentally and numerically obtained results related to the orientation of steel fibres and related to the mechanical properties of the material.The aforementioned results are linked together in Section 3.3.Discussion of the results is pro-vided in Section 4.Section 5concludes the article.2.Materials and methodsThe following subsections describe experiments that were con-ducted to verify the hypothesis that formwork surface can influ-ence the orientation of fibres immersed in self-compacting concrete and,consequently,the mechanical response of the struc-ture.The numerical simulations,which were used to strengthen and complement the experimental observations,are also briefly introduced.2.1.ExperimentsSix slabs of fibre reinforced self-compacting concrete were cast using formwork of three different surface types.The following sub-sections describe the casting process of the slabs,methods for quantifying the orientations of fibres immersed in the slabs,and the subsequent mechanical testing of beam specimens cut from the slabs.2.1.1.Mixture design and casting processSix slabs of dimensions 1.2m Â1.2m Â0.15m were cast of fi-bre reinforced self-compacting concrete.The casting process was conducted from a rubber pipe inlet positioned near one of the cor-ners of the slab (Fig.2).The point of discharge was located at 0.2m above the base of the slab.Mixture design of the self-compacting concrete was:cement =388kg =m 3,silica fume =19:4kg =m 3,natural sand ð0—8mm Þ¼1182kg =m 3,crushed stone ð8—16mm Þ¼570kg =m 3,super plasti-ciser =4:66kg =m 3and air entrainer (1:7)=0:97kg =m 3.The water ce-ment ratio was 0.505.At the time of mixing,the fine and coarse aggregates were in the saturated-surface-dry condition.Hooked end steel fibres (Bekaert Dramix RL 80/60BN)were gradually added to the self-compacting concrete during the mixing process.The fibre volume ratio was 0.5%,corresponding to 40kg/m 3.The fibre length and the fibre diameter were 60mm and 0.75mm,respectively.Density of the steel fibres was 7850kg/m 3.Three different formwork surfaces were employed in the Supplementary video.The video a shows casting process of steel fibre self-compacting concrete into a formwork of three different surface roughnesses.O.Švec et al./Cement &Concrete Composites 50(2014)60–7261which shows the casting of the fibre reinforced self-compact-ing concrete into the glue-laminated plywood formwork,ordin-ary plywood formwork and into the glued-sand plywood formwork.Rheology of the fresh fibre reinforced self-compacting concrete was evaluated during the casting process by means of the stan-dardized slump flow test according to EN 12350-2.Spread of the slump was measured and read 620mm.Rheological parameters,following a Bingham plastic rheological model,were obtained by means of 4C-Rheometer [13].Yield stress and plastic viscosity of the fibre reinforced self-compacting concrete were estimated to be 22Pa and 75Pa s,respectively.The measured density and air content of the fresh concrete were 2318kg/m 3and 3.5%,respectively.After casting,the slabs were covered with cloth saturated with water.The slabs were then sealed within a polyethylene film and left to harden for a period of 28days at ambient temperatures.In total six beam specimens of dimensions 0.6m Â0.15m Â0.15m were then cut out from each of the slabs,as indicated by the 1red and green prisms in Fig.4.Orientation of the steel fibres present in the beams specimens was studied by means of the computed tomography and subse-quent image analysis.The resulting mechanical response of the beam specimens was studied by means of the three-and four-point bending tests.puted tomography and image analysisComputed Tomography (CT)is an advanced radiographic tech-nique for obtaining 3D images of the internal structure of an ele-ment.The method has been among others widely used in the field of steel fibre reinforced concrete [1,14–16].The CT and subse-quent image analyses were employed to obtain a 3D representa-tion of the steel fibres located in the beam specimens.The 3D representation was subsequently approximated by a set of 3D ori-entation tensors [17].We used a former medical CT scanner,Siemens Somatom Sen-sation 4,to scan three beam specimens out of each slab.The three scanned beam specimens are depicted in Fig.4as red prisms.Sequential spine routine of the medical CT scanner was employed to interpret approximately 600successive slices normal to the x axis (Fig.4).A typical slice image produced by the CT scanner is presented in Fig.5.The red regions in Fig.5b are the voxels with maximum brightness.The red regions were obtained by threshold-ing the image.The zone marked by the green rectangle in Fig.5b reveals that not only fibres but also parts of aggregates are marked in red.This is caused by a relatively low tube voltage of the medical CT scanner and results in a more complicated image analysis.An open-source application Fiji 2was used to crop,threshold and skeletonise the sequence of the approximately 600successive slice images.The skeletonisation technique of the Fiji application output-ted a skeleton,i.e.a large set of 3D line segments located in space.Fig.6as an example shows a small part of the skeleton.Red region in Fig.6shows 3D line segments that were probably created by skeletonising aggregates depicted in Fig.5b.Fig.6re-veals that although the majority of the 3D line segments represent individual parts of steel fibres,some of the 3D line segments rep-resent other concrete constituents such as aggregates.The primary interest of the paper is to study orientation of steel fibres.The 3D line segments were therefore converted into a set of second-order orientation tensors [17].The second-order tensors can be visual-ised by means of 3D ellipsoids in space or by means of 2D ellipses in plane.All the CT scanned beam specimens were volumetrically split into a series of cubic regions (see Fig.7b for a 2D projection).Sec-ond-order orientation tensors were computed for all the 3D line segments located in each of the cubic regions.Fig.7c illustrates the second-order tensors by projecting the 3D orientation ellip-soids into 2D orientation ellipses.The second-order orientation tensors can be computed as [17]:a ij ¼1tPLp x p xP Lp x p y P Lp x p zPLp y p yP Lp y p z sym :PLp z p z264375;ð1Þwhere the summation is taken through all the line segments located in the cubic region of interest.Values of p x ;p y and p z are compo-nents of the normalised vector pointing in the direction of the indi-vidual line segments located in the cubic region of interest.Valueofsurface views of three different formwork types.(a)Glue-laminated plywood.(b)Ordinary plywood.(c)Glued-sand1For interpretation of colour in Figs.4–6,the reader is referred to the web version of this article.2http://fiji.sc/.L is the length of the individual line segments length of the line segments located in the L t ¼P L .The summation of the main diagonal of must be equal to unity,i.e.,a 1;1þa 2;2þa directions of the axes of the orientation ellipsoids eigenvalues and eigenvectors of the second-order sors,respectively.Results of the computed are presented in Section 3.1.1.2.1.3.Three-and four-point bending testsAll the six beam specimens indicated obtain their mechanical response in flexure.depicted by green prisms in Fig.4were bending according to the Norwegian sawn After the CT scanning,as presented in specimens depicted as red prisms in Fig.vide a notch at mid-span and tested according to EN 14651.During the test,the beam specimens were oriented in the casting direction,such that the tensile face was the bottom cast surface of the beam which EN 14651.Fig.8depicts a typical fracture of bending test.The degree of planarity of that these surface views of fracture represent pattern well.Fig.5.(a)A typical slice image of the scanned beam specimens.(b)Regions with the maximum brightness.6.Result of the skeletonisation technique of the CT images.Black lines are the individual 3D line segments.(a)(b)(c)7.Process for obtaining the second-order orientation tensors:(a)skeleton image of fibres within beam specimen;(b)volumetric discretization into cubic regions;and (c)second-order tensor representation of fibre orientation within each 8.A typical frontal view of the fractured beam specimens.Top:three-point bending test.Bottom:four-point bending test.CMOD.For the four-point bending tests,load and respective mid-span deflections of the beam specimens,d m,were recorded.For the purpose of comparing results of the different types of beam tests,an effective CMOD for the case of four-point bending was computed based on[18]ascmod4pt¼4h d ml4pt;ð2Þwhere hð¼0:15mÞis the height of the beam specimen and l4ptð¼0:45mÞis the distance between the beam supports.In the case of the three-point bending tests,theflexural stresses of beam specimens were computed as[19]r3pt¼3Fl3pt2bh2sp;ð3Þwhere bð¼0:15mÞis the width of the beam specimen and h spð¼0:125mÞis the distance between tip of the notch and top of cross section[20].Value of l3ptð¼0:5mÞstands for the span between the beam supports.In the case of the four-point bending tests,theflexural stress of a beam specimen was computed asr4pt¼Fl4ptbh:ð4ÞResults of the three-and four-point bending tests are presented in Section3.2.1.2.1.4.Fibre count local to the fracture planeSection2.1.2described the process of scanning of the beam specimens depicted by red prisms in Fig.4.For each3D image of the beam specimens produced by CT scanning,we selected the im-age slice located closest to the fracture plane.The number of steel fibres crossing the fracture plane was estimated by manually counting thefibres visible on the slice images similarly to [10,?,21,22].In addition,all the beam specimens tested by the three-and four-point bending tests were cut in the vicinity of the main crack. The cut plane was polished and the number of steelfibres visible at the cut plane was manually counted.The number of steelfibres crossing the fracture plane or the cut plane was related to theflex-ural stresses of the individual beam specimens at an arbitrarily chosen crack mouth opening displacement,as will be presented in Section3.3.2.2.Numerical simulationsTwo distinct types of numerical simulation were run to strengthen the experimental observations and to shed light on the phenomenological processes observed in the experiments. Thefirst type simulates theflow of thefibre reinforced self-com-pacting ingfibre coordinate data from theflow simu-lations,the second type simulates the fracture behaviour of the hardenedfibre reinforced self-compacting concrete.2.2.1.Numerical simulation offlowIn recent years there have been growing fundamental and prac-tical interests in numerically simulating theflow of concrete mate-rials,includingfibre reinforced concrete[23].Roussel et al.[24] review the advantages and disadvantages of several strategies for simulating concreteflow.We have developed a numerical frame-work capable of predictingflow of explicitly represented rigid par-ticles immersed in the free surfaceflow of a homogeneous non-Newtonianfluid,such as fresh concrete.One of the primary goals of the numerical framework has been to quantitatively predict the distribution and orientation of the steelfibres immersed in the self-compacting concrete during casting.The numerical frame-work is explained in detail in[25].We discussed the implementa-tion of the immersed rigidfibres into the framework in[26].The ability of the numerical framework to properly simulate various formwork surfaces was introduced in[27].Fig.9presents a3D view of the numerical simulation of slab casting at an intermediate step.The numerical simulation was run with the same physical input parameters(fluid density,yield stress plastic viscosity,fibre type,etc.)as presented in Section 2.1.1.As a possibility for future research,the determination of in-put parameters could be supported by predictive models[28,29]. The numerical framework is devoid of any non-physical input parameters.The self-compacting concrete was modelled as a free surfaceflow of a homogeneous Bingham plasticfluid.The steel fibres were modelled as thin rigid cylinders immersed in the homogeneousfluid.The steelfibres were modelled explicitly,one by one,including various features of the numerical framework such as the two-way coupled interaction between thefluid and thefibres,plastic collisions among thefibres or plastic collisions of thefibres with the formwork.The formwork was modelled as Navier’s slip boundary condition of a specific Navier’s slip length [27].Thefluid domain was discretized as1cm=1discrete unit.In total three different numerical simulations were run differen-tiated by the type of the formwork surface used in the numerical simulation.The three different Navier’s slip lengths were then equal to0cm,8cm and1.Each numerical simulation was run in parallel on25computer cores and lasted approximately4days.The peak number of explic-itly simulated steelfibres was approximately41,000.Results of the numerical simulation offlow are presented in Section3.1.2.2.2.2.Numerical simulation of fracture behaviourA lattice-type model is used to simulate the fracture behaviour of thefibre-reinforced concrete.Both the matrix andfibre element formulations are based on the concept of a rigid-body-spring mod-el,as described in previous publications[30–32].The concrete ma-trix is assumed to be homogeneous and exhibit bilinear softening after fracture.Material disorder is solely due to the presence of the short-fibre reinforcement,which is explicitly represented within the model framework.Domain discretization is based on the Delaunay/Voronoi tessellation of a set of nodes[33].Discretiza-tion of thefibre-reinforced concrete specimens is presented in Fig.10a.Stiffness contributions of thefibres before concrete cracking are derived from elastic shear lag theory.After concrete cracking,fibre contributions to strength and stiffness across the open crack ac-count for debonding and slip at thefibre–matrix interface.The ef-fect of the hooked end of thefibres was approximated as a frictional force,distributed uniformly over thefibre embedded length.The pullout behaviour of individualfibres was modified to account for snubbing effect and the potential for matrix spalling whenfibres are lowly inclined to the fracture plane[34].The lattice model was used to simulate fracture behaviour of each of the four-point bend tests(B1a,B2a,and B3a)for the case of glue-laminated plywood as formwork.This case exhibited the largest variation in load–displacement behaviour with respect to beam position in the slab.Thefinal positions of the steelfibres within the cast slab spec-imens were supplied by the aforementioned numerical simulations offlow.Thereafter,the slabs were sectioned to produce models of the beam specimens,as shown in Fig.4,in a way that mimicked the physical cutting process.Fibres intersecting the cut planes were cut at the point of intersection,retaining the portion inside the beam volume.Fig.10b as an example illustrates steelfibres present in one of the tested beam specimens.64O.Švec et al./Cement&Concrete Composites50(2014)60–72Fracture of the beam specimens was restricted to occur along the central plane within the beam span(see Fig.10).This simplifi-cation allows for the grading of nodal point density in the vicinity of the crack plane to reduce computational expense.As discussed later,however,restricting the location of cracking can affect the mechanical response of the beams.Tensile strength of the matrix and the pullout resistance of individualfibres were adjusted to achieve rough agreement between the load–displacement curve of the model and that of the B1a specimen.The following settings were used as a result of the calibration process:uniaxial tensile strength r t¼2MPa; r1¼r t=4;w1¼0:05mm;traction-free crack opening displace-ment w c¼0:3mm;and frictional resistance s f¼4MPa[31].The same parameter set was then used for the simulations of specimens B2a and B3a.The results for specimens B2a and B3a can be therefore viewed as predictive simulations.The assumptions made herein,including thefitting of param-eter values for the B1a specimen,were deemed reasonable for achieving the primary goal of the fracture simulations,which is to demonstrate the effects offibre distribution on the fracture behaviour of theflexural specimens.Results of the numerical simulation of fracture behaviour are presented in Section3.2.2.3.ResultsThis section presents results obtained by CT scanning and by the three-and four-point bending tests.These experimental results are then compared to results obtained from their respective numerical simulations.3.1.Fibre orientationThe following two subsections study the average planar(x–y) orientation of the steelfibres by means of the second-order orientation parisons are made between the orienta-tion of the steelfibres obtained by experiments and the results ob-tained by the numerical simulations that we developed.puted tomography and image analysisFig.11presents projected top views of the orientation ellipsoids for the bottom half of the CT scanned beam specimens for the dif-ferent formwork surfaces.The positions of the beam specimens (CT1,CT2,CT3)within the cast slabs are indicated in Fig.4.Fig.11a and b indicates that the ordinary plywood formwork and the glued-sand plywood formwork provide similar orientations of the immersed steelfibres in the bottom half of the slabs.Steelfibres in the bulk of beam specimens CT1and CT2seem to be more or less randomly oriented as there is no prevailing pattern of the orienta-tion ellipses.The steelfibres become fairly oriented along the y coordinate at the bottom and top edges of the beam specimens CT1and CT2,respectively.This is caused by the wall-effect induced by the vertical parts of the formwork.Beam specimens CT3of Fig.11a and b reveal a slight degree of orientation of the steelfibres along the x coordinate.By observing Fig.11a and b,we can conclude that the ordinary plywood formwork and the glued-sand plywood formwork possess similar apparent slip characteristics.At the bottom half of the slabs,the rough surface of the formwork seems to result infibre orientations that are more or less independent of theflow pattern.Fig.11c on the other hand shows a completely different pattern of the orientation of the steelfibres.The observation suggests that,3D view of the simulated slab casting at an intermediate step.Left:immersed steelfibres.Right:Bingham plastic four-point bend specimen under loading and(b)fibres within the computational domain for specimen B1a(forwithin the bottom half of the slab,the fibres tend to orient under the flow of the self-compacting concrete when a smooth-surface formwork such as glue-laminated plywood is applied.Fig.12presents the experimentally obtained orientation of the steel fibres for the upper half of the slabs for the three formwork surfaces.Contrary to Fig.11,all results indicate a similar pattern in which fibres seem to be oriented according to the flow of the self-compacting concrete.Fig.12c indicates a slightly higher de-gree of the orientation of the steel fibres compared to those of Fig.12a and b but the difference is much less pronounced than for the case of the bottom half of the slabs.3.1.2.Numerical simulation of flowThe casting process of the slabs of the three formwork surfaces was simulated by means of the numerical framework that we developed and have described in [25–27].The formwork of the castslabs was modelled using Navier’s slip boundary condition.Numerical simulations were run for Navier’s slip lengths of 0cm,8cm and 1.The numerically obtained orientation of the steel fibres was subsequently compared to the experimental results presented in Section 3.1.1.Fig.13shows the resulting orientation of the steel fibres for the slab with Navier’s slip length equal to 0cm.The orientation of the steel fibres is depicted as the top view projection of the orientation ellipsoids (marked with black stroke).Within the bottom half of the slab (Fig.13a ),the steel fibres tend to orient in the regions close to the vertical walls of the formwork,which is primarily caused by the wall effect.In the bulk of the slab,the steel fibres remain in a more or less random orientation state.In the upper half of the slab (Fig.13b ),the steel fibres exhibit a relatively high degree of orientation following the flow pattern of the self-compactingconcrete.66O.Švec et al./Cement &Concrete Composites 50(2014)60–72O.Švec et al./Cement&Concrete Composites50(2014)60–7267Fig.13also compares the simulated fibre orientations with the experimentally measured orientations for the bottom and upper halfs of the slab.The comparison indicates a relatively high degree of agreement between the experimentally and numerically ob-tained results.The comparison indicates that glued-sand plywood formwork or formworks of similar roughness can be successfully modelled using the Navier’s slip boundary condition with a slip length of 0cm.Fig.14presents the simulated fibre orientations for the slab with Navier’s slip length equal to 8cm .In the bulk of the bottom half of the slab (Fig.14a ),the steel fibres seem to orient to a higher degree compared to the slab with slip length equal to 0cm (see Fig.13a).The steel fibres of the upper half of the slab exhibit a high degree of orientation,following the flow pattern of the self-com-pacting concrete.The results of the numerical simulation agree well with the experimental (CT)results for the slab having the glue-laminated plywood as the formwork (Fig.14).Fig.15presents the orientation of the steel fibres for the extreme case of the Navier’s slip length equal to 1.In such a case the steel fibres exhibit a high degree of orientation in all the parts of the slab,except for immediately under the inlet pipe.There were no respective experimental results for comparison with these numerical results.3.2.Mechanical propertiesThis subsection illustrates the influence of the formwork sur-face on the mechanical properties of the fibre reinforced self-com-pacting concrete material.Results of the three-and four-point bending tests are presented.For the case of glue-laminated ply-wood formwork,tested under four-point bending,the experimen-tal results are compared to those of the lattice model simulations.3.2.1.Three-and four-point bending testsFigs.16–18present mechanical responses of the beam speci-mens for the three different formwork surfaces in terms of load–displacement curves.Two nominally identical slabs were cast for each formwork surface type and,therefore,two flexural test results are provided for each case.Individual plots thus contain results of two beam specimens of the same origin,e.g.B1,a and B1,b.Fig.16indicates a substantial difference in the flexural behav-iour of the individual beam specimens,ranging from deflection hardening to almost complete loss of residual strength after first cracking.For example,beam specimens marked CT3and B3expe-rience more than 5Âand 10Âhigher post-cracking strengths com-pared to beam specimens CT1and B1,respectively.The observations suggest that,when using a smooth-surface formwork,structural elements extracted from different locations can possess considerably diverse mechanical properties.Figs.17and 18on the other hand indicate a significantly lower spread of the flexural stresses of the individual beam specimens.The highest post-cracking strength of the beam specimens is approximately 2Âhigher compared to the lowest mechanical re-sponse of the beam specimens.Structural elements cast into form-work with a rough surface generally seem to result in considerably less diverse mechanical properties compared to the structural elements cast into a formwork with a smooth surface.Relative to the four-point bending tests,the three-point bending tests exhibit higher peak strengths and somewhat larger variations of the load–displacement curves.The higher strengths are likely caused by restricting fracture to occur from the notch at midspan.The four-point loading configuration produces a larger volume of highly stressed material and allows for failure to occur at potentially weaker locations.Markovic [35]observed less engagement of the hooked end of steel fibres during fracture of unnotched specimens,compared to notched specimens.The unnotched case facilitates fracture along paths of least resistance that,to some degree,avoid full deformation of the fibre hooks during pullout.Such behaviour contributes to lower strength and toughness of unnotched speci-mens.The larger variation in the load–displacement curves of the three-point bending tests is likely due to variations in fibre count and fibre orientation in the ligament zone above the notch tip.How-ever,additional data points are needed to make statistically signif-icant conclusions regarding differences between the three-and four-point bending test results.3.2.2.Numerical simulation of fracture behaviourFracture behaviour of the four-point bend specimens,taken from the slab having glue-laminated plywood as the formwork,was numerically simulated by means of the lattice model.Fig.19presents both the numerically and experimentally obtained load–displacement curves for beams B1a,B2a and B3a.As explained in Section 2.2.2,model parameters were adjusted to achieve close agreement with the load–displacement curve of beam B1a.The same parameter set was used for beams B2a and B3a,so the corre-sponding simulations may be viewed as predictions.The trends with respect to first cracking strength,peak strength,and evolution of post-cracking residual strength are in good qualitative agree-ment with the experimental results.3.3.Fibre count local to the fracture planeThis subsection relates the number and orientation of the im-mersed steel fibres to the fracture behaviour of the beam speci-mens in a quantitative manner.Fig.20presents flexuralstresses68O.Švec et al./Cement &Concrete Composites 50(2014)60–72。

力学名词中英对照2007-12-15 09:59:20 楼主A 安全因数safety factorB半桥接法half bridge闭口薄壁杆thin-walled tubes比例极限proportional limit边界条件boundary conditions变截面梁beam of variable cross section变形deformation变形协调方程compatibility equation标距gage length泊松比Poisson's ratio补偿块compensating blockC材料力学mechanics of materials冲击荷载impact load初应力，预应力initial stress纯剪切pure shear纯弯曲pure bending脆性材料brittle materialsD大柔度杆long columns单位荷载unit load单位力偶unit couple单位荷载法unit-load method单向应力，单向受力uniaxial stress等强度梁beam of constant strength低周疲劳low-cycle fatigue电桥平衡bridge balancing电阻应变计resistance strain gage电阻应变仪resistance strain indicator叠加法superposition method叠加原理superposition principle动荷载dynamic load断面收缩率percentage reduction in area多余约束redundant restraint2E二向应力状态state of biaxial stressF分布力distributed force复杂应力状态state of triaxial stress复合材料composite materialG杆，杆件bar刚度stiffness刚架，构架frame刚结点rigid joint高周疲劳high-cycle fatigue各向同性材料isotropical material功的互等定理reciprocal-work theorem工作应变计active strain gage工作应力working stress构件structural member惯性半径radius of gyration of an area惯性积product of inertia惯性矩，截面二次轴距moment of inertia广义胡克定律generalized Hook's lawH横向变形lateral deformation胡克定律Hook's law滑移线slip-linesJ基本系统primary system畸变能理论distortion energy theory畸变能密度distortional strain energy density极惯性矩，截面二次极矩polar moment of inertia 极限应力ultimate stress极限荷载limit load挤压应力bearing stress剪力shear force剪力方程equation of shear force剪力图shear force diagram剪流shear flow剪切胡克定律Hook's law for shear剪切shear3交变应力，循环应力cyclic stress截面法method of sections截面几何性质geometrical properties of an area截面核心core of section静不定次，超静定次数degree of a statically indeterminate problem 静不定问题，超静定问题statically indeterminate problem静定问题statically determinate problem静荷载static load静矩，一次矩static moment颈缩neckingK开口薄壁杆bar of thin-walled open cross section抗拉强度ultimate stress in tension抗扭截面系数section modulus in torsion抗扭强度ultimate stress in torsion抗弯截面系数section modulus in bendingL拉压刚度axial rigidity拉压杆，轴向承载杆axially loaded bar理想弹塑性假设elastic-perfectly plastic assumption力法force method力学性能mechanical properties连续梁continuous beam连续条件continuity condition梁beams临界应力critical stress临界荷载critical loadM迈因纳定律Miner's law名义屈服强度offset yielding stress莫尔强度理论Mohr theory of failure敏感栅sensitive gridN挠度deflection挠曲轴deflection curve挠曲轴方程equation of deflection curve挠曲轴近似微分方程approximately differential equation of the deflection curve 内力internal forces扭力矩twisting moment扭矩torsional moment4扭矩图torque diagram扭转torsion扭转极限应力ultimate stress in torsion扭转角angel of twist扭转屈服强度yielding stress in torsion扭转刚度torsional rigidityO欧拉公式Euler's formulaP疲劳极限，条件疲劳极限endurance limit疲劳破坏fatigue rupture疲劳寿命fatigue life偏心拉伸eccentric tension偏心压缩eccentric compression平均应力average stress平面弯曲plane bending平面应力状态state of plane stress平行移轴定理parallel axis theorem平面假设plane cross-section assumptionQ强度strength强度理论theory of strength强度条件strength condition切变模量shear modulus切应变shear strain切应力shear stress切应力互等定理theorem of conjugate shearing stress屈服yield屈服强度yield strength全桥接线法full bridgeR热应力thermal stressS三向应力状态state of triaxial stress三轴直角应变花three-element rectangular rosette三轴等角应变花three-element delta rosette失稳buckling伸长率elongation5圣维南原理Saint-V enant's principle实验应力分析experimental stress analysis塑性变形，残余变形plastic deformation塑性材料，延性材料ductile materials塑性铰plastic hingeT弹簧常量spring constant弹性变形elastic deformation弹性模量modulus of elasticity体积力body force体积改变能密度density of energy of volume change 体应变volume strainW弯矩bending moment弯矩方程equation of bending moment弯矩图bending moment diagram弯曲bending弯曲刚度flexural rigidity弯曲正应力normal stress in bending弯曲切应力shear stress in bending弯曲中心shear center位移法displacement method位移互等定理reciprocal-displacement theorem稳定条件stability condition稳定性stability稳定安全因数safety factor for stabilityX细长比，柔度slenderness ratio线性弹性体linear elastic body约束扭转constraint torsion相当长度，有效长度equivalent length相当应力equivalent stress小柔度杆short columns形心轴centroidal axis形状系数shape factor许用应力allowable stress许用应力法allowable stress method许用荷载allowable load许用荷载法allowable load method6Y应变花strain rosette应变计strain gage应变能strain energy应变能密度strain energy density应力stress应力速率stress ratio应力比stress ratio应力幅stress amplitude应力状态state of stress应力集中stress concentration应力集中因数stress concentration factor应力－寿命曲线，S-N 曲线stress-cycle curve 应力－应变图stress-strain diagram应力圆，莫尔圆Mohr's circle for stressesZ正应变normal strain正应力normal stress中面middle plane中柔度杆intermediate columns中性层neutral surface中性轴neutral axis轴shaft轴力axial force轴力图axial force diagram轴向变形axial deformation轴向拉伸axial tension轴向压缩axial compression主平面principal planes主应力principal stress主应力迹线principal stress trajectory主轴principal axis主惯性矩principal moment of inertia主形心惯性矩principal centroidal moments of inertia 主形心轴principal centroidal axis转角angel of rotation转轴公式transformation equation自由扭转free torsion组合变形combined deformation组合截面composite area最大切应力理论maximum shear stress theory。

第32卷 第5期 岩 土 工 程 学 报 Vol.32 No.5 2010年 5月 Chinese Journal of Geotechnical Engineering May 2010岩土应变硬化指数理论及其分数阶微积分理论基础殷德顺，和成亮，陈 文(河海大学工程力学系，江苏 南京 210098)摘 要：应变硬化型岩土的三轴试验应力应变曲线能够表现出不同的弯曲程度，而应力应变曲线的弯曲程度是岩土应变硬化能力的体现，但已有的研究中还没有相应的参数来描述岩土的硬化能力。

为了获得反映岩土应变硬化能力的参数，从而有助于了解岩土的塑性性能和指导土体的合理承载，根据Hollomon 提出的描绘金属塑性拉伸变形的指数方程（经验公式），提出了岩土应变硬化指数理论。

通过许多三轴试验，发现岩土应变硬化指数理论提出的岩土应力应变关系符合乘幂函数关系的假设能够被验证，岩土的应变硬化指数能够反映岩土的硬化能力。

岩土的力学性质介于理想固体和理想流体之间，其应力应变关系既不遵守胡克定律，也不遵守牛顿黏性定律，而是遵守介于它们之间的某种关系。

利用分数阶微积分理论给出了恒应变率加载情况下的土应力应变关系。

关系式显示应力应变之间也呈乘幂函数关系，说明岩土分数阶应力应变关系能够为岩土应变硬化指数理论提供理论基础。

关键词：应变硬化指数；分数阶微积分；三轴试验；理论基础中图分类号：TU43 文献标识码：A 文章编号：1000–4548(2010)05–0762–05作者简介：殷德顺(1972– )，男，副教授，主要从事土的本构模型及基本理论研究。

E-mail: yindeshun@ 。

Theory of geotechnical strain hardening index and its rationale fromfractional order calculusYIN De-shun, HE Cheng-liang, CHEN Wen(Department of Engineering Mechanics, Hohai University, Nanjing 210098, China)Abstract : The curvature of stress-strain curves from triaxial tests on harden soil is a reflection of hardening ability, but there isn’t a parameter of hardening ability in geotechnical mechanics. In order to gain such a parameter that can help us to know plasticity and proper bearing capacity of soil, a theory of geotechnical strain hardening index (TAGSHI) in response to exponential equation (an empirical equation) which Hollomon established from experience in metal tensile deformation is developed. Based on a lot of triaxial tests, it is shown that the assumption in TAGSHI is right, which thinks that stress-strain relationship of soil is the power function in triaxial tests, and the strain hardening index may reflect geotechnical hardening ability. As we all know that geotechnical mechanical property should be intermediate between that of an ideal solid and an ideal fluid, so its stress-strain relation should neither follow the Hook’s law nor obey the Newton's law of viscosity, and it should be consistent with the fractional expression ()d ()d t t t ββσε=, (01β<<). The geotechnical stress-strain relation is derived byapplying the theory of fractional order calculus operator under the condition of loading with constant strain rate. The analytic results show that the geotechnical stress-strain curves exhibit power relation, and it is consistent with the assumption in TAGSHI. This indicates that the fractional expression ()d ()t t t ββσε=, (01β<<) can give a rationale for TAGSHI.Key words : strain hardening index; fractional order calculus; triaxial test; rationale0 前 言常规三轴试验是研究岩土材料力学性质的重要手段，无论是砂土[1]、黏土[2-3]，还是岩石材料[4]，它们的三轴试验已经积累了大量的试验数据和经验。

Improved model for plate-end shear of CFRPstrengthened RC beamsOmar Ahmed,Dionys Van Gemert *,Lucie VandewalleDepartment of Civil Engineering,Katholieke Universiteit Leuven,W.De Croylaan 2,B-3001Heverlee,BelgiumReceived 27August 1999;accepted 21September 2000AbstractIn case of RC members strengthened by means of externally bonded reinforcement,a premature failure can be detected in addition to the conventional modes of failure observed in RC unstrengthened beams.The premature failure occurs mainly due to both shear and normal stresses induced in either the external reinforcement±concrete interface or at the level of steel reinforcement.This research is part of a complete programme aiming to set up design formulae to predict the strength of CFRP strengthened beams,particularly when premature failure through laminates-end shear or concrete cover delamination occurs.Series of RC beams were strengthened with carbon-®ber-reinforced plastic (CFRP)laminates and tested to estimate the extent of the applicability of the formulae proposed by the authors,as well as to study the in¯uence of the layout of the external reinforcement in terms of unsheeted length (the distance between CFRP laminates-end and the nearer support)and cross-sectional area,on the behaviour of strengthened beams.The predictions using the proposed formulae are compared with the obtained experimental results,as well as with the calculated design limit states.The interfacial shear stress and the maximum de¯ection corresponding to the predicted values at maximum and service loads are also studied.Ó2001Elsevier Science Ltd.All rights reserved.Keywords:Carbon-®ber-reinforced plastic (CFRP)laminates;Anchorage shear stress;Strengthening;Shear-span;Unsheeted length1.IntroductionCarbon-®ber-reinforced plastic (CFRP)laminates are becoming a powerful technique for strengthening RC beams.The technique intends to enhance the ¯exural capacity of the original beam.However,when applying the CFRP laminates to the beam,geometrical as well as material discontinuities are introduced into the com-posite system (beam/adhesive/laminates).Similarly,as in the steel plate bonding technique,the unsheeted length in the shear zone near the beam sup-ports has an important e ect on the general behaviour and strength of the system.Due to higher strength of the laminates,their cross-sectional area is reduced,and therefore the geometrical relation between concrete and laminates is completely di erent from the one in bonded steel plates.In steel plate bonding only exceptionally more than one layer of plates are used.However,in CFRP lami-nates bonding,it is very easy to comprise of multiple laminates and laminate layers with di erent lengths.The use of di erent lengths can be applied to alleviate stress concentration at the laminates anchorages [1].This paper deals with mathematical modelling and prediction of behaviour and strength of CFRP lami-nates strengthened beams,in particular when failure occurs due to laminates-end shear or concrete cover delamination,taking into account the in¯uence of un-sheeted length and the cross-sectional area of CFRP.This paper does not deal with other failure mechanisms like peeling-o of laminates at the laminates ends or at intermediate locations such as large shear or ¯exural cracks [2].Tests on a series of RC beams with externally bonded CFRP laminates have been used in this research to con®rm the validity of the proposed formulae to be applied in the case of CFRP strengthened beams in both ultimate and design limit states.Cement &Concrete Composites 23(2001)3±19*Corresponding author.Fax:+32-016-321976.E-mail address:dionys.vangemert@bwk.kuleuven.ac.be (D.Van Gemert).0958-9465/01/$-see front matter Ó2001Elsevier Science Ltd.All rights reserved.PII:S 0958-9465(00)00051-22.Mathematical modelling2.1.Shear stress analysisFor a homogeneous beam,Kim and White[3]ana-lysed the shear stress induced over the surface in a horizontal cross-section at the level of the internal bars as well as at that in a vertical cross section.After the formation of¯exural cracks,the shear stresses over the surface in a horizontal cross-section do not remain constant but change considerably,see Fig.1(c).Equi-librium of an element pp H m H n H(Fig.1(b))is considered, with the reinforcement tension force T acting on the ¯exural crack.The average shear stress s avg acting on the horizontal plane pp H is obtained according to(Eq.(1)). Eq.(1)needs a careful consideration because of the discontinuities caused by cracking and complexities in stress distribution caused by the composite action of steel and concrete.More speci®c,these discontinuities are caused by the e ect of bond between the concrete and the rebar and the e ect of the development of arch action.After the¯exural crack n H p H forms(Fig.1(b)),bond phenomena lead to highly concentrated shear stresses in the zone above the internal bars,adjacent to the ¯exural crack(Figs.1(a),(b)and(d)).In the critical zone,a maximum shear stress is present,with a value of double or more the average stress.Hence,a mag-ni®cation factor m bond is introduced which,according to Kim,is equal to or more than2.On the other hand, the neutral axis shifts upward after the occurrence of ¯exural cracks,(Fig.2).In the shear-span,the real le-ver arm tends to be smaller than the one calculated by means of the cracked section analysis.Kim explains this by the fact that when¯exural cracks extend,the compressive stress distribution becomes more uniform. Accordingly,the neutral axis shifts downward.This is attributed to the development of arch action.As a re-sult of the reduction of the internal lever arm from z0 to z c(Fig.2(a)),the reinforcement force T in the shear-span is consistently higher than the calculated value. Hence,a magni®cation factor m arch is introduced,which equals the actual internal moment arm length z c over the calculated moment arm z0.With regard to Kim's4O.Ahmed et al./Cement&Concrete Composites23(2001)3±19explanation,it is remarked that the increased rein-forcement force is normally accounted for by the so-called ``shift-rule''in a cross-section.It is calculated with the shear load acting on the concrete compression zone of the cross-section at the tip of the ¯exural crack (Fig.2(b)).On the basis of these considerations Kim and White derived two cracking criteria.The ®rst criterion,(Eq.(2)),describes the ¯exural shear cracking load,when the shear stress s reaches the tensile strength f t of concrete.Then,a shear crack may initiate at a point in the critical zone in which the magni®cation factors m arch and m bond only have a meaning after ¯exural cracking.For a simply supported beam under point loads,the second criterion,(Eq.(3)),describes the shear force as a function of the ¯exural cracking moment at a section a c from the sup-port.By equilibrating the two criteria,a probable ¯exural shear load and a ¯exural shear crack position a c emerge.The critical crack position a c is expressed by Eq.(4).sT ba c; 1 V cr 1m arch m bond f t bz 0;2 V cr M cr a c 3anda c k 3q s d s =a21À q sp ÀÁ2451=3a4with q s reinforcement ratio and k 3 empirical con-stant.2.2.Modelling analogy according to Jansze [4]If RC members are partially strengthened by means of externally bonded steel plates,a plate-end shear crack is forced to occur at the plate-end location.Hence,the plate-end position or the unplated length L is analogous to the location of the critical shear crack a c of Kim and White.This is depicted in Fig.3.On the left side,thecritical crack section of Kim and White is depicted,the right side shows a partially plated beam-end.As a result of the analogy between a c and L ,the shear-span a be-longing to a c is analogous to the ®ctitious shear-span a L belonging to L .When taking this modelling analogy into account,Eq.(4)can be interpreted as Eq.(5).The ®ctitious shear-span a L given by Eq.(5)is used by Jansze as input parameter to compute the shear resistance s cum on the basis of MC905-formula (7)[5],where C MC90 k 0:18(Eq.(10))in case of ultimate load.Es-sential is that with this MC90-formula the unstrength-ened part is considered,so the e ective depth of the internal reinforcement d s and the internal reinforcement ratio q s have to be taken into account.Kim has used a statistical analysis to determine the constant k 0included in Eq.(4).Also,to satisfy the prediction of the maximum shear load,the formulation has been adjusted by Jansze [4].Analysis showed that by replacing the constant k 0included in Eq.(5)by the ®ctitious shear-span-to-depth ratio a L =d s ,a correct agreement was obtained between the plate-end shear loads based on the ®ctitious shear-span and the experimental and numerical results.Thus,by substituting constant k 0in Eq.(5)with a L =d s it can be rewritten into Eq.(6)that objectively expresses the ®cti-tious shear-span a L .Hence,when Eq.(6)is used in combination with the modi®ed MC90(Eq.(10))to pre-dict the plate-end shear strength s PES of strengthened beams with di erent unplated lengths [4],the conclusion is drawn that the plate-end shear model is de®nitely ca-pable of calculating the plate-end shear strength of par-tially plated members with various cross-sections.L k 0q s d s =a L21À q sp ÀÁ2451=3a L ;5a L1À q sp ÀÁ2q s d s L 34s ; 6s cumC MC90 3d s a 3r 12200d s s 3 100q s f cm 3p CEB ÀFIP MC90 :7O.Ahmed et al./Cement &Concrete Composites 23(2001)3±195Furthermore,throughout the experiments carried out by Jansze on strengthened beams of di erent concrete sec-tions as well as throughout various other studies [6,7]on plate-end shear and plate separation,Jansze found that the described plate separation loads showed a lower bound value (x À1:64s )of 0.84in the case of steel plates and 0.83for the FRP plates.As a result,a characteristic lower bound of 0.83times the mean maximum shear load is advised.Then the plate-end shear model should be multiplied by a factor 0.83for a safe design.As a consequence,the constant k 0:18in Eq.(10)should be replaced by the design factor 0:83Â0:18 0:15.Moreover,the mean value of the concrete cylinder compressive strength should be replaced by the charac-teristic compressive cylinder strength.Then the design for plate-end shear and plate separation can be obtained according to Eqs.(6)and (10).It is worthwhile to mention that the modi®ed MC90formula is corres-ponding to the shear cracking stress as recommended by the MC90code for reinforced concrete beams.Ac-cordingly,the plate-end shear model is a lower bound model for the maximum shear load and for plate sepa-ration by concrete cover rip-o .2.3.Proposed analytical modelThe common dominant failure mode of RC beams strengthened with externally bonded CFRP laminates is the premature one,either laminates-end shear or con-crete cover delamination.Therefore,the signi®cant pa-rameter a ecting the failure behaviour of a strengthened beam is the shear stress in the adhesive layer between the external reinforcement and the concrete s tot .The critical section locates at the longitudinal laminates-end region (cut-o point),where the shear stress concentration oc-curs.Such a shear stress is partially due to the variation of bending moment,part s SF ,and the remaining part due to the introduction of forces in the anchoring zones,part s anch (anchorage shear stress).The ®rst portion of shear stress has a considerable role in the case of steel plate bonding.On the contrary,that portion of shear stress is considerably smaller in the case of CFRP lam-inates technique (Fig.4).This is attributed to the lower sti ness of the externally bonded reinforcement in case of CFRP laminates:the CFRP laminates strength amounts to 7±10times that of steel plates,and the modulus of elasticity of the CFRP laminates used in the experimental programme is greater than that of steel plates.A much smaller area of laminates is thus nor-mally needed.Due to the speci®c shear stress situation mentioned before,and based on Eq.(10),suggested by Jansze,the authors propose modi®ed formulae to predict the load carrying capacity of RC beams strengthened by means of externally bonded CFRP laminates,particularly for those failed due to either laminates-end shear or con-crete cover delamination.Therefore,the shear strength s PES (PES plate-end shear)calculated from Eq.(10)will be replaced by s FES (FES ®ber-end shear).The authors propose to add the modi®cation D s MOD given in Eq.(11)to obtain s FES instead of s PES ,(Fig.5and Eqs.(8)±(12)).The proposed modi®ed expression relies mainly on adding the di erence between the portion of shear stress generated due to shear force in case of substitution of CFRP laminates with steel plates of 550N =mm 2yield strength (the case of Jansze's study)and that for CFRP laminates,to the shear stress calculated from Eq.(10).Moreover,contribution of the original shear strength of the beam to be strengthened to the obtained strength is taken into account [8].The second term in Eq.(11)dealing with the in¯uence of the original shear strength is added to the formula presented in the literature [1,9].This term accounts for an original shear strength s (s is calculated according to ACI code [10],Eq.(12))di erent from that of reference strengthenedbeams.Fig.4.Shear stresses in the external reinforcement±concrete interface.6O.Ahmed et al./Cement &Concrete Composites 23(2001)3±19The ®ctitious shear-span a L calculated according to Eq.(6)may be greater than the true shear-span a .A ®ctitious shear-span a L larger than the true one a is not logic.In such cases,Jansze proposed to limit a L to the true value a .In our experiments,we found that an imaginary value a LM equal to the average of the calcu-lated ®ctitious shear-span and the true shear-span should replace the value a L included in Eq.(10).This adaptation is always applied by the authors.F FES s FES bd s 6F u ; 8 s FES s PES D s MOD ; 9s PESk 3d s L3r 12200s s 3 100q s f c 3p Jansze ;1997 10D s MOD s PES bd sS p I p WÀS FI F W m m s Às ref bd s; 11s 0:15776 f c p17:2366q s F u dM u0:9ÂA st f ystsbACI Code ; 12where k ;m ;s ref are 0.18,6188.5and 4.121in case of maximum load and are 0.15,7236.5and 2.75in case of design load,S F ;I F the statical moment of area and moment of inertia of transformed (to concrete)cracked section in case of CFRP,S P ;I P the statical moment ofarea and moment of inertia of transformed (to concrete)cracked section in case of replacing CFRP with steel plates,q s the ratio of continuous tension reinforcement,f c the mean compressive cylinder concrete strength,W ;W m the widths of both CFRP and epoxy mortar,respectively (Fig.5(b)),M u =F u represents the shear-span (a ),A st ;f yst the cross-sectional area and yield strength of shear reinforcement,s the spacing between internal stirrups,F u is the smaller of either shear capacity or ¯exural capacity of the strengthened beam (P 2F ).3.Outline of experiments 3.1.Test programmeNine RC beams with a rectangular cross-section of125mm width and 225mm height were tested under a two-point loading bending test over a simple span of 1500mm (shear-span to depth ratio,a =d ,equals 2.5).These beams were divided into two main groups.The beams in the ®rst group were designated as AF.0,AF.2,AF.2-1,AF.3and AF.4.These beams were rein-forced with two bottom bars (A s )of 8mm in diameter and two top bars of 6mm in diameter plus stirrups of 6mm in diameter at a spacing (s )of 71mm (Fig.6).The ®rst beam AF.0was tested in its original condition as a control one.The rest of the beams were strengthened with two layers of longitudinal CFRP laminates (A F )of 75mm width and variable lengths (Table 1and Fig.7).These two layers were bonded symmetrically onto the bottom concrete surface of the beam.The main pa-rameter taken into account in this group is the distance between the cut-o point and the nearer support,the so-called unsheeted length (L ).The beams in the second group were designated as CF.3-0,DF.1,DF.2and DF.4.These beams were re-inforced with three tension bars of 8mm in diameter (A s )and two top bars of 6mm in diameter plus stirrups of 6mm in diameter at a spacing (s )(Fig.6and Table 1).The ®rst beam CF.3-0was the control one.Beams DF.1,DF.2and DF.4were strengthened with one,two and four layers of longitudinal CFRP laminates,respec-tively.Both the length and width of longitudinal CFRP laminates are the same and equal to 1400and 75mm,respectively (unsheeted length to shear-span ratio L =a 0:10)as shown in Fig.3and Table 1.For this group of beams,the main parameter is the cross-sec-tional area of the CFRP laminates.3.2.MaterialsAll beams were made using a normal strength coarse aggregate concrete of 16mm maximum nominal size,350kg =m 3Portland cement (CEM I,42.5)and a w/c of 0.55.This concrete mix achieved mean compressive strength,surface tensile strength (pull-o strength)and Young's modulus of 45.0,2.85and 30000MPa,respectively.The mean compressive strengths (f c )onthe cylinder after 42days (time of testing)are listed in Table 1for the di erent tested beams.Ribbed bars (BE 500)of 8mm in diameter were used for tension reinforcement and of 6mm for both com-pression and web reinforcements (stirrups).Both yield and ultimate strengths as well as Young's modulus for each diameter are mentioned in Table 2.The external reinforcement was a CFRP laminate [11].Such a CFRP is available in rolled laminate of 0.167mm e ective thickness,500mm width and 100m length.The e ective thickness gives the section of the ®bers in each single ply.The ultimate strength (rupture strength)and Young's modulus of the CFRP laminate are given in Table 2.An epoxy mortar layer of 2.5±3.5mm thickness was applied to the di erent strengthened beams as aTable 1Details and data of tested beams Beam no.Internal reinforcement f c (MPa)Epoxy mortar CFRP laminates NoticeA ss (mm)L H (mm)W m (mm)A F (mm 2)L (mm)AF.041.0))))Ref.AF.241.020012525.05200AF.2-12U 8mm 7141.015012525.05150AF.341.010012525.05100AF.441.05012525.0550CF.3-07143.0))))Ref.DF.142.03212512.5350DF.23U 8mm10042.04312525.0550DF.440.55012550.1050Table 2Properties of used reinforcements Properties (N =mm 2)Internal reinforcement Externalreinforcement U 6(mm)U 8(mm)(CFRP laminate)Yield strength 553568)Ultimate strength 6136543500Young's modulus195000185000240000substratum to the CFRP laminates.This epoxy mor-tar is almost completely cured within a period of24h after application.Then the compressive,bending and tensile strengths as well as Young's modulus of this epoxy mortar amount to80,20,6.5and7200N=mm2, respectively.The resin used for the completion of CFRP impregnation was a special epoxy resin,which was developed for an easy impregnation of the lami-nate.3.3.Preparation of test specimensThe beams were prepared for bonding after a period of3weeks from casting.The concrete surfaces where the epoxy mortar layer was applied were roughened using sand-blasting technique.Before the application of the epoxy mortar,the roughened surfaces were cleaned by brushing and compressed air to remove any attached ®ne materials.4.Experimental results and discussionThe in¯uence of both the unsheeted length and the amount of externally bonded CFRP laminates on the behaviour of tested beams are discussed.Table3gives the following elements:4.1.Failure behaviourThe®rst crack initiated as a¯exural one at the middle third(region of constant moment)in case of both ref-erence and strengthened beams.The mode of failure was a¯exural one for the reference beams.However,it changed from laminates-end shear to concrete cover delamination as the unsheeted length decreased(Fig.8). The results recorded by Oehlers[2,12,13]concerning the failure mode con®rm the obtained results.When con-sidering the cross-sectional area of the CFRP laminates, the failure mode changed from a¯exural one(yielding of internal steel bars and rupture of CFRP laminate)to concrete cover delamination to laminates-end shear as the amount of CFRP increased(Fig.9).The obtained results showed a similar trend to that observed by Tu-mialan[14].Furthermore,it is worth noting that the growth load was a ected considerably by the variation of the unsheeted length:it increased as the unsheeted length decreased(Table3).On the contrary,it was found that the growth load was not in¯uenced signi®-cantly by the variation of the amount of the externally bonded CFRP laminates.4.2.Maximum loads and load±de¯ection diagramsThe used strengthening technique enhanced the cracking load.The obtained enhancement was not af-fected by the variation of the unsheeted length.How-ever,it was in¯uenced reasonably by the variation of the amount of externally bonded CFRP laminates.When considering the load carrying capacity P max,the strengthened beams showed a considerable enhance-ment in comparison to that of the corresponding refer-ence beam.The unsheeted length showed a signi®cant e ect on the load carrying capacity(Fig.18).On the contrary,the gained strength did not correspond to the increase in the amount of CFRP,particularly at a higherP cr cracking loadP gr growth load(load at which the end lam-inates shear crack initiates)P max ultimate rupture loadd cr mid-span de¯ection at®rst crackingd max maximum mid-span de¯ection(the de¯ec-tion corresponding to the maximum load)s tot maximum interfacial shear stress inducedalong the bonded lengths SF interfacial shear stress due to shear force.Table3Results of tested beamsBeam no.Loads(kN)Shear stress(MPa)De¯ection(mm)Mode of failure P cr P gr P max s SF s tot d cr d maxAF.020.0)55.0))0.7710.60Flexure/ref.AF.225.055.083.00.47 1.17 1.068.44Laminates-end shear AF.2-125.060.085.70.51 1.21 1.0110.16Laminates-end shear AF.325.065.096.50.54 1.45 1.0813.16Laminates-end shear AF.425.0105.0111.00.63 2.230.8714.63Concrete coverCF.3-020.0)75.0))0.6411.16Flexure/ref.DF.125.0105.0118.00.28>1.720.7820.80Flexure aDF.230.0100.0120.00.51 1.84 1.0113.60Concrete coverdelaminationDF.428.0100.0125.00.87 1.980.9110.00Laminates-end sheara Flexure due to yielding of internal steel and rupture of externally bonded CFRP laminates.O.Ahmed et al./Cement&Concrete Composites23(2001)3±199strengthening ratio (A F =A s ),(Fig.19).The load carrying capacity of the strengthened beam increased as the strengthening ratio increased.However,for strengthen-ing ratios higher than about 8%,a very slight enhance-ment was observed in the gained strength as the strengthening ratio increased.This does not mean that the value of 8%of the experiments is the common op-timum strengthening ratio.The optimum value relies mainly on di erent other parameters such as the original shear strength,the original ¯exural strength,the con-crete strength and the shear-span to depth ratio of the member to be strengthened [8,15±17].When considering the maximum load,the strengthened beams showed 1.51,1.56,1.75and 2.02times the load of the corre-sponding reference beam for unsheeted length of 200,150,100,50mm,respectively.On the other hand,the strengthened beams showed 1.57,1.61and 1.67times that of the corresponding reference beam for strength-ening ratio (A F =A s )of 8.05%,16.1%and 32.2%,re-spectively.The studies of Tumialan [14]and Kachlakev [18]con®rm the obtained results well.The relation between the total applied load and the measured mid-span de¯ection is illustrated in Figs.10and 11for tested beams with di erent unsheetedlengthsFig.9.Crack pattern of beams DF.1,DF.2and DF.4(A F 12:53,25.05and 50.1mm 2).Fig.8.Crack pattern of beams AF.2and AF.4(L 200and 50mm).10O.Ahmed et al./Cement &Concrete Composites 23(2001)3±19and di erent amounts of CFRP laminates,respectively.Through these ®gures it is obvious that,for the same level of loading,the strengthened beams showed a smaller mid-span de¯ection than that of the corre-sponding reference beams,particularly after cracking.Before cracking,the used strengthening technique showed no signi®cant in¯uence.On the other side,when considering the relative load (the ratio of the applied load to the maximum load)the strengthened beams showed a greater de¯ection than that of the corre-sponding reference beams at the same relative load.The unsheeted length has a slight in¯uence on the mid-span de¯ection,particularly at lower loading levels.Con-trarily to this,a reasonable in¯uence on the bending sti ness emerged due to the variation of the amount of externally bonded CFRP laminates regardless of the loading level.This is attributed to the active contribu-tion of the amount of external longitudinal reinforce-ment to the overall bending sti ness of the strengthenedbeam.O.Ahmed et al./Cement &Concrete Composites 23(2001)3±19114.3.Interfacial shear stressesThe shear stress evolution(s)between the external reinforcement and concrete along the bonded length was derived from the normal stresses of CFRP laminates(r) according to Eq.(13),in which i and iÀ1denote the subsequent cross-sections.The di erence between the stresses generated in the subsequent CFRP laminates cross-sections is transmitted to the concrete by shear stresses.s ir i t f i Àr iÀ1 t f iÀ1D x i: 13For the various unsheeted lengths as well as for the various amounts of externally bonded CFRP laminates, the shear stress distribution was plotted along the bonded length for di erent levels of loading as shown in Figs.12±15.At the CFRP laminates-end region,at the same level of loading,the shear stress decreased as the unsheeted length decreased.Such a laminates-endshear12O.Ahmed et al./Cement&Concrete Composites23(2001)3±19stress plays a major role in the initiation and propaga-tion of the laminates-end shear crack which is normally considered the major crack in case of strengthened beams.The total drop in the shear stress induced at the laminates-end region,just before failure,increased as the unsheeted length increased.Through Fig.13and Table3it can be observed that the value of maximum shear stress generated at the external reinforcement±concrete interface along the bonded length enhanced considerably as the unsheeted length decreased.This is due to the fact that the concentration and widths of both shear and¯exural shear cracks formed at the laminates-end region increased as the unsheeted length increased. These formed cracks weaken the surface tensile strength of the concrete.In case of beams with di erent strengthening ratios A F=A s(A s is constant)and at the same level of loading, the shear stress generated at the CFRP laminates-end region increased as the cross-sectional areas of CFRP laminates increased(Fig.14).The total drop in shear stress induced at the laminates-end region,just before failure,increased as the cross-sectional area ofCFRPlaminates increased.Contrarily to that of unsheeted length,the cross-sectional areas of bonded CFRP lam-inates showed a slight in¯uence on the value of maxi-mum shear stress generated along the bonded length just before failure(Fig.15and Table3).5.Evaluation of the proposed formulae5.1.Maximum loadThe predicted load carrying capacity of the strengthened beams obtained according to both the analytical model(P pr)proposed by the authors and Jansze's equation(P pr:J)was calculated.Also,the maxi-mum¯exural capacity for the di erent tested beams was calculated according to Eurocode2[19].Two values could be obtained according to the proposed analytical model,P pr:a and P pr:b.The®rst value P pr:a is obtained when applying the unsheeted length L to calculate the ®ctitious shear-span a L.Yet,the second one P pr:b is ob-tained when applying the unstrengthened length L H,the distance between the edge of the epoxy mortar layer and the nearer support(clearance of the layer of the epoxy mortar is taken into account),instead of the unsheeted length L to calculate the®ctitious shear-span,(Fig.7). Herewith,the mathematical model takes into account that the end-laminate shear crack(major crack corre-sponding to P gr)starts at the end of the epoxy mortar layer,and not at the end of the laminate.Fig.16shows the ideal case with a major crack which initiated at the end of bonded longitudinal laminates and Fig.17shows the case with a major shear crack which initiated at the end of the epoxy mortar layer.The comparison between the predicted load carrying capacity and that obtained experimentally is illustrated in Figs.18,19and Table4.The calculated results ob-tained according to the proposed formulae show a much better approach to the observed values in comparison with those obtained according to the existing literature [4],particularly when the clearance of the epoxy mortar layer is taken into account.5.2.Design load and serviceability limit stateThe proposed equation is modi®ed in case of a design procedure for both laminates-end shear and concrete cover delamination.Moreover,limitations of the pro-posed formulae accommodate the conventional failure modes,shear one and¯exural one.The ultimate limit state(ULS)design method may be used in these two cases.A good design not only takes into account the ULS,but it also guarantees a ductile behaviour to allow for a stress distribution.In some particular cases,the strengthened beams showed a ductile behaviour,e.g.beams of higher shear-span to depth ratio(a=d>2:5)[17]and those provided with adequate end anchorage[1].The results of the various previous studies on RC beams strengthened by means of externally bonded reinforcements proved that the failure response of the member and the bonded ex-ternal reinforcement were characterised as brittle.Ac-cordingly,when one should design these brittle failure modes,a lower bound approach of the maximum load carrying capacity is recognized.The safety againstfail-Fig.16.Major shear crack at the end of bonded laminates.。

写在前面春回大地，万象更新，在这春意盎然的时节里，新一期《图书馆最新资源速递》又如期与您见面了。

根据广大读者的需求，今年我馆在购置中文期刊时，新增订了近200种，为了方便您查找，我们已编制了《河海大学图书馆2008年度馆藏中文期刊目录》，并分发给各单位。

同时，我们将这近200种新增订的中文期刊目录单独列出，编辑在本辑《图书馆最新资源速递》的最后，以节省您查找新刊的时间。

本期继续报道外文会议录信息，希望我们的外文会议录专集对您查找会议文献有所帮助。

《图书馆最新资源速递》编辑体例如下：1、整体按分类编排：由于我馆的中文期刊是按《中图法》分类，中外文图书及外文期刊是按《科图法》分类，而这两种分类法又不尽相同，故我们将这两种分类的大类进行比较，相对集中并于目录中体现，目的是使推介的每一学科的内容尽量集中，以便读者更方便的使用；2、每一大类的内容按最新中文期刊目录、最新外文期刊目录、中文图书提要、外文图书提要的顺序编排；3、每一种推介的文献都注明了我馆的馆藏地。

4、我们的联系方式是：读者服务部（西康校区）：电话：83787308、83787307、83787302E-mail：zhongqz@ tsgxp@ tsgcbb@读者服务部（江宁校区）：电话：83787648E-mail：tsgcm@本期责任编辑：中文期刊——梁军；中文图书——许平；外文期刊——余清芬；外文图书——杨小莉。

本期供稿人员：周冰杨小莉宋艺丁马大勇郑林吴丽娣刘忠锦邓鸣超杨露曦熊易胡玲玲吴立志王唏红封丽陆艳洪建河海大学图书馆读者服务部2008. 4.3目录20 社会科学（C 社会科学总论） (5)中文期刊 (5)27 经济、经济学（F 经济） (9)中文期刊 (9)中文图书 (16)31/34 政治、社会生活/法律、法学（D 政治、法律） (17)中文期刊 (17)中文图书 (22)37 文化、科学、教育、体育（G 文化、科学、教育、体育） (27)中文期刊 (27)41 语言、文字学（H语言、文字） (29)中文期刊 (29)50 自然科学（N 自然科学总论） (31)中文期刊 (31)51-54 数学/力学/物理学/化学（O 数理科学和化学） (33)中文期刊 (33)中文图书 (36)外文期刊 (36)55-56 天文学/地球科学（P 天文学、地球科学） (58)中文期刊 (58)外文期刊 (60)58 生物科学(Q 生物科学) (87)中文图书 (87)65 农业科学（S 农业科学） (88)中文期刊 (88)中文图书 (89)外文期刊 (90)71-86 技术科学（T/X 工业技术/环境科学、安全科学） (91)中文期刊 (91)中文图书 (104)外文期刊 (136)外文会议录 (195)河海大学图书馆2008年新增中文现刊馆藏目录 (253)20 社会科学（C 社会科学总论）中文期刊社会科学[月刊]=Jornal of Social Sciences/上海社会科学院.—10期，2007年.—上海：上海社会科学院《社会科学》编辑部，（200020）.15.00元ISSN 0257-5833 CN 31-1112索书号：C/5 馆藏地：西康校区四楼本期目录内容新苏南模式与两新·组织党建运行机制——以江苏昆山市为实例…………………王世谊 (4) 政府在公民维权中的指导责任和接受监督……………………………………………汤啸天(16) 地方政府考核：双重委托人失效及其政策含义………………………………徐风华王俊杰(25) 泛长江三角洲：世界第六大都市圈未来“一体两翼·新格局…………………………张颊瀚(34) 税费改革后农村公共服务提供机制的比较研究——基于湖北与浙江农村的调查………………………………………………………………………………伏玉林符钢战(40) 论上海发展面临的虚拟经济膨胀问题…………………………………………………高炜宇(47) 社会情境理论：贫困现象的另一种解释…………………………………………………周怡(56) 浦东新郊区建设和人口城市化再推进研究……………………………………………孙嘉丰(63) 后形而上时代的“沟通主义法律观”——啜法律的沟通之维》代译序………………邓正来(69) 单位人格刑事责任沦纲……………………………………………………………………杜文(72) 沦行政行为的代表性…………………………………………………………樊明亚赖声利 (80) 对我国学前教育改革若干问题的文化观照……………………………………………华爱华(87) 《沦语》：孔子弟子博弈之成果——兼谈战国后期儒家八派之争及荀卿的态度……李露平(96) 中西和谐社会思想之异同：经济学说史的视角………………………………………钟祥财(105) 清末新政对民生问题的恶性操作与社会矛盾的激化…………………………………陆兴龙(115) 《月令》；农耕民族的人生模型……………………………………………………………薛富(123) 书生立武勋——湘军功成的内在因素…………………………………………………李志茗(134) 塞上海柴拉报势考略……………………………………………………………………褚晓琦(147) 墓惠与商道：近代上海慈善组织兴起的原因探析……………………………………汪华(154) 走向·间性哲学·的跨文化研究…………………………………………………………周宁(162) 空间，性别与认同——女性写作的·地理学·转向…………………………………陈惠芬（170）月西方理论和方法解析中国古代诗词——叶嘉莹中西诗学研究之阐释……………徐志啸（183）法商研究[双月刊]=Studies in LAW And Business/中南财经政法大学.—第1期，2008年.—武汉市：《法商研究》编辑部，（430073）.18.00元ISSN 1672-0393 CN 42-1664/D索书号：C5/73 馆藏地：本部四楼本期目录内容“美国对华铜版纸案”述评——基于反补贴申诉的考察……………………李仲平李炼(3) 美国反补贴法适用探析——以对“非市场经济国家”的适用为考察对象…………徐泉(10) WTO法律体系下实施“双反”措施的合法性研究——由“美国对华铜版纸案”引发的思考………………………………………………………………………………………臧立(16)从立法中心主义转向司法中心主义?——关于几种“中心主义”研究范式的反思、延伸与比较……………………………………………………………………………………喻中(22) 转化型抢劫罪主体条件的实质解释——以相对刑事责任年龄人的刑事责任为视角………………………………………………………………………………………刘艳红(29) 论我国股权激励的本土创新——股权分置改革视野下的反思与重构………………官欣荣(42) 论以人为本的“人”……………………………………………………………………胡锦光(48) 限时刑法探究……………………………………………………………………………黄明儒(55) 农民土地产权资本化经营实现的法律保障……………………………………………李丽峰(61) 城市土地节约利用法律制度：现状、问题与对策……………………………………王文革(69) 论现行保证制度的局限及其完善——以成本收益分析为中心………………………许德风(78) 保护传统文化的政策目标论纲…………………………………………………………黄玉烨(86) 我国新能源与可再生能源立法之新思维………………………………………………杨解君(92) 美国监管影响分析制度述评……………………………………………………………马英娟(98) 论犯罪的相对性——从绝对理性到相对理性…………………………………………张建军(107) 基于信息的荐证广告之法律规制——以保健品广告为中心…………………………吴元元(113) 环境罚款数额设定的立法研究…………………………………………………………程雨燕(121) 委托调解若干问题研究——对四个基层人民法院委托调解的初步考察……………李浩(133) 中国法律史研究思路新探………………………………………………………………邓建鹏(141) 中国法学会商法学研究会2007年年会综述…………………………………………冯兴俊(147) 第十五届全国经济法理论研讨会综述…………………………………………………管斌(153)复印报刊资料·社会学[月刊]Sociology.—第2期，2008年.—北京：中国人民大学书报资料中心，（100086）.10.00元ISSN 1001-344X CN 11-4250/C索书号：C91/3 馆藏地：本部四楼江宁二楼本期目录内容理论研究中国社会发展范式的转换：普遍性与特殊性……………………………………………刘新刚(3) 欧洲社会模式的反思与展望……………………………………………(英)安东尼·吉登斯(10) 分支学科自我行动与自主经营——理解中国人何以将自主经营当作其参与市场实践的首选方式……………汪和建(21) 声望危机下的学术群体——当代知识分子身份地位研究……………………………刘亚秋(37) 中国城市教育分层研究(1949-2003) …………………………………………………郝大海(51) 法律执行的社会学模式——对法律援助过程的法社会学分析………………王晓蓓郭星华(63) 社会发展系统打造农村现代职业体系的创新探索——武汉农村家园建设行动计划和实践的社会学分析之一……………………郑杭生(69) “活着的过去”和“未来的过去”——民俗制度变迁与新农村建设的社会学视野…………………………………杨敏(76) 社会问题解决社会问题的关键：协调好社会各群体之间的关系…………………………………李强(87) 环球视窗美国式的贫困与反贫困...........................................................................张锐(89) 索引 (92)英文目录 (96)领导科学[半月刊]=Leadership Science—第21期，2007年.—河南：领导科学杂志社编辑出版，（450002）.3.80元ISSN1003-2606 CN41-1024/C索书号： C93/8 馆藏地：本部四楼江宁二楼本期目录内容领导科学界的首要政治任务…………………………………………………………本刊编辑部（1）学习贯彻十七大精神把思想和行动统一到党的十七大精神上来——在2007年度省领导与社科葬专家学者座谈会上的讲话…………………………………………………………………………………徐光春（4）新一届中央领导集体治国理政的新方略(上) …………………………………………姜平（9）理论前沿关于领导、发展、以人为本的关系解读…………………………………………………王伟凯（ll）领导方法有效解决集体上访问题的思考与实践…………………………………………………陈丰林（14）引导信访户从“上访路”走上“致富路”………………………………………………邱金义（16）增强班子合力关键要合理分工…………………………………………………………枣甘（13）高校党建工作进网络的探索…………………………………………………张进超詹爱琴（17）市县领导欠发达地区构建和谐社会的着力点……………………………………………………丁善余（20）拓展农业发展思路的五种渠道…………………………………………………………盛高攀（22）乡镇领导推进乡镇党委和谐班子建设的途径……………………………………………………王晓宏（23）乡镇党委如何统揽工作全局……………………………………………………………刘久正（25）职工论坛建立体现科学发展观要求的干部政绩考核机制………………………………………盛克勤（30）组织部门信访工作机制探索……………………………………………………………钟群妹（26）用人之道有效规范干部选任初始提名工作……………………………………………李明辉韩振松（32）如何用好有过失的干部…………………………………………………………………蒋红波（34）办公室领导办公室工作如伺体现科学发展观要求…………………………………………………王合清（36）怎样在被动服务中求得主动……………………………………………………………方黎（38）学术动态中国领导科学研究会2007年年会将在上海市召开 (43)领导决策实现政府公共决策机制法治化的基本途径……………………………………………李光明（40）领导素养领导行为与对人的认识…………………………………………………………………周丽丽（42）军事领导基层政治工作如何贯彻科学发展观……………………………………………………鲁鸿飞（44）培养官兵对制度的敬畏感………………………………………………………………何洪江（46）领导鉴戒“大胜”更须戒骄………………………………………………………………………李颖（48）领导作风领导工作应坚持“三真”原则………………………………………………余丰立朱伟（47）外国政要帕蒂尔：温和印度的政治选择……………………………………………………………史泽华（50）治政史鉴朱元璋的反贪之策………………………………………………………………………韩立竖（52）特别阅读真相(中篇小说梗概) (54)热风细雨“经济提拔”与“提拔经济”…………………………………………………………江波（35）新视野(十七大的历史地位和历史意义)等7篇 (18)中国人才[半月刊]= Chinese Talents Magazine．—第10期，2007年．—北京：中国人才杂志社，（100101）．6.00元ISSN 1003-4072 CN 11-2455/C索书号：C96/5 馆藏地：西康校区四楼江宁校区二楼本期目录内容人才精论“以人才为本”是人才开发的核心 (1)瞭望要闻.政策法规.声音.动态.数字信息 (4)考录：严把公务员“入口”关倡培养造就高素质公务员队伍 (10)人才市揭：为人才成长提供良好机遇与环境 (12)高校毕业生就业服务成效显著 (14)聚焦人事争议仲裁制度迈向新的发展 (15)完善人事争议仲裁构建和谐社会——《人事争议处理规定》解读 (16)努力开创人事争议仲裁工作新局面 (20)“六大人才高峰”彰显人才集聚效应 (21)高技能人才从何而来 (23)造福于民方能造福于己 (25)以.三最.为民生轴心彰显科学发展 (25)理论研究区分公共服务与经营性服务的理论思考 (26)探寻人才科学开发之道 (29)如何实施人才激励 (31)人才铺就小康路·走进昆山实施“人才强市”大战略加速“两个率先”新征程——本刊专访中共昆山市委书记张国华 (38)广纳八方英才创新昆山发展 (42)人才亮点点亮昆山 (44)名家在线科学大家平民本色——记中国测绘科学研究院名誉院长、中国工程院院士刘先林眉 (56)群星闪烁 (59)公务员管理提高公务员考试科学性 (61)加强县乡公务员队伍建设必须从优化人员结构入手 (63)“在线学习”引领干部培训“网络化” (66)事业单位聘用制推行中常见问题与对策分析 (68)如何做好当前外国专家管理与服务工作 (68)西部地区海外引才的一道亮丽风景线 (70)巧用职称评聘“杠杆”支撑人才活力 (72)人才资源配置流动人员人事档案管理难点与对策 (74)搞好毕业生人事档案管理 (77)县域人才开发如何与国际化接轨 (79)集团文化建设落地的关键点 (80)国有企业“二线”人员的开发 (81)简明定位“薪”事不再重重 (83)公备员在受处分期间受到新的处分，处分期如何计算 (85)未满服务期辞职应如何承担违约责任 (86)27 经济、经济学（F 经济）中文期刊世界经济[月刊]=The Journal of World Economy /中国经济学会中国社会科学院世界经济与政治研究所．—第2期，2008年2月．—北京：《世界经济》编辑部，（100732）．15.00元ISSN1002-9621 CN11—1138/F索书号：F1/45本期目录内容国际贸易与国际投资研发全球化与本土知识交流：对北京跨国公司研发机构的经验分析…………………………………………………………………梁正，薛澜，朱琴，朱雪炜(3) 区际壁垒与贸易的边界效应…………………………………………赵永亮，徐勇，苏桂富(17) 国际金融国际分工体系视角的货币国际化：美元和日元的典型事实……………………徐奇渊，李婧(30) 存在金融体制改革的“中国模式”吗…………………………………………………应展宇等(40) 宏观经济学习惯形成与最优税收结构…………………………………………………………邹薇，刘勇(55) R&D溢出渠道、异质性反应与生产率：基于178个国家面板数据的经验研究……………………………………………………………………………高凌云，王永中(65) 中国经济三种自主创新能力与技术进步：基于DEA方法的经验分析……………李平，随洪光(74) 经济史明代海外贸易管制中的寻租、暴力冲突与国家权力流失：一个产权经济学的视角……………………………………………………………………………………郭艳茹(84) 会议综述第一届青年经济学家研讨会(YES)综述 (95)经济与管理研究[月刊]=Research on Economics and Management/首都经济贸易大学．—第2期，2008年2月．—北京：《经济与管理研究》编辑部，（100026）．10.00元ISSN1000-7636 CN11—1384/F索书号：F2/8本期目录内容会议纪要努力探索中国特色国有公司治理模式——中国特色国有公司治理高层论坛综述 (5)专题论坛改革开放与国有经济战略性调整………………………………………………………王忠明(13) 股权多元化的国有控股公司治理结构特点及其构建………………………………魏秀丽(21) 剩余权的分配与国企产权改革……………………………兰纪平，罗鹏，霍立新，张凤环(28) 企业创新需求与我国自主创新能力的形成：基于收入分配视角………………………张杰，刘志彪(33) 集成创新过程中的三方博弈分析……………………………………………宋伟，彭小宝(38) 创新与企业战略制定模式的演进………………………………………刘鹏，金占明，李庆(43) 企业管理大型国际化零售企业经营绩效的影响因素分析………………………………蔡荣生，王勇(49) 跨团队冲突与组织激励机制分析………………………………………………李欣午(54) 运用基尼系数增强企业薪酬制度的公平性……………………………王令舜，马彤(59) 三农研究乡村旅游发展的公共属性、政府责任与财政支持研究……………单新萍，魏小安(64) 论失地农民长效保障机制的构建………………………………………………魏秀丽(69) 资本市场外资银行进入与东道国银行体系的稳定性：以新兴市场国家为例………………张蓉(74) 挤兑风险与道德风险的权衡：显性存款保险制度下最优保险范围的制定…冯伟，曹元涛(80) 贸易经济在反倾销中对出口商利益的考量………………………………………………金晓晨(86) 我国加征出口关税政策思辨…………………………………………夏骋祥，李克娟(90) 名刊要览公司治理和并购收益 (94)规制——自由化的必由之路：以色列电信市场1984-2005 (94)金融与收入分配不平等：渠道与证据 (94)特别主题论坛：重新审视组织内部和组织自身的“污名”问题 (95)经济理论与经济管理[月刊]= Economic Theory and Business Management.—第11期，2007年.—北京：《经济理论与经济管理》编辑部，（100080）.8.00元ISSN 1000-596X CN 11-1517/F索书号：F2/12 馆藏地：本部四楼江宁二楼本期目录内容深入贯彻落实科学发展观的经济视阈……………………………………………………张雷声(5) 科学发展观与中国特色社会主义经济理论体系的创新与发展…………………………张宇(9) 关于转变经济发展方式的三个问题……………………………………………………方福前(12) 统筹城乡协调发展是落实科学发展观的重大历史任务………………………………秦华(16) 中国进出口贸易顺差的原因、现状及未来展望………………………………王晋斌李南(19) 劳动力市场收入冲击对消费行为的影响………………………………………杜凤莲孙婧芳(26) 中国经济增长中土地资源的“尾效”分析……………………………………………崔云(32) 货币需求弹性、有效货币供给与货币市场非均衡模型解析“中国之谜”与长期流动性过剩……………………………………………………………………………………李治国 (38) 全流通进程中的中国股市全收益率研究………………………………………陈璋李惊(45) 金融体系内风险转移及其对金融稳定性影响研究……………………………………许荣(50) 金融衍生品交易监管的国际合作……………………………………………………谭燕芝等(56) 税收饶让发展面临的挑战及我国的选择………………………………………………张文春(61) 区域产业结构对人民币升值“逆效应”的影响………………………………………孙伯良(66) 企业社会责任管理新理念：从社会责任到社会资本……………………………………易开刚(71) 关于建设创新型国家的讨论综述………………………………………………………杨万东(76)经济理论与经济管理[月刊]= Economic Theory and Business Management.—第1期，2008年.—北京：《经济理论与经济管理》编辑部，（100080）.8.00元ISSN 1000-596X CN 11-1517/F索书号：F2/12 馆藏地：本部四楼江宁二楼本期目录内容经济热点中国宏观经济形势与政策：2007—2008年………………………中国人民大学经济学研究所(5) 理论探索出口战略、代工行为与本土企业创新——来自江苏地区制造业企业的经验证据…张杰等(12) FDI在华独资化的动因——基于吸收能力的分析……………………………秦凤鸣张中楠(20) 学术前沿主权财富基金的发展及对21世纪初世界经济的影响………………………宋玉华李锋(27) 公共经济环境税“双重红利”假说述评……………………………………………………………司言武(34) 基于合谋下的税收征管激励机制设计………………………………………………岳朝龙，等(39) 金融研究内生货币体系下房价波动对货币供求的冲击…………………………………丁晨屠梅曾(43) 基于DEA的中小企业债务融资效率研究………………………………………曾江洪陈迪宇(50) 区域经济地区经济增长中的金融要素贡献的差异与金融资源配置优化——基于环北部湾(中国)经济区的实证分析…………………………………范祚军等(54) 工商管理基于价值链的预算信息协同机制研究………………………………………………张瑞君，等(59) 公司特征、行业特征和产业转型类型的实证研究……………………………王德鲁宋学锋(64) 国际经济基于市场体系变迁的中国与欧洲银行业发展比较……………………………胡波郭艳(70) 动态与综述我国发展现代农业问题讨论综述………………………………………………………王碧峰(75) 全国马克思列宁主义经济学说史学会第十一次学术研讨会纪要……………………张旭(80)国有资产管理[月刊]= State assets management /中国人民共和国财政部.-第1期，2008年.—北京：《国有资产管理》杂志社，(100036) .10.00元ISSN 1002-4247 CN 11-2798索书号：F2/51 馆藏地：西康校区四楼本期目录内容贯彻落实科学发展观开创中央企业又好又快发展新局面.................................李荣融（4）努力做好新形势下的监事会工作..................................................................黄丹华（8）资产评估行业发展的重要里程碑...............................................................朱志刚（13）加快评估立法步伐加强评估法律体系建设................................................石秀诗（15）资产评估行业将进入新的发展时期............................................................李伟（16）提升资产评估执业质量促进资本市场健康发展..........................................李小雪（17）评估准则对中国不动产及相关资产评估的作用..............................埃尔文.费南德斯（18）发挥评估准则对中国资产评估行业健康发展的作用.......................................林兰源（20）正确发展适合中国国情的评估准则..........................................格来格.麦克纳马拉（21）财政部国资委关于印发《中央企业国有资本收益收取管理暂行办法》的通知 (22)财政部关于印发《中央国有资本经营预算编报试行办法》的通知 (25)力口快建立国有资本经营预算推动国民经济又好又快发展..............................贾谌（28）关于国有企业改制和整体上市..................................................................季晓南（30）加快建立科学规范的财务监督体系............................................................孟建民（39）贯彻科学发展观’开创财务监督管理工作新局面..........................................赵杰（43）寓监管于服务之中——对做好四川国资监管工作的思考.................................李成云（47）努力实现广西区国资国企健康发展............................................................尹建国（49）新企业会计准则对国资监管可能带来的影响................................................安玉理（52）2007年宏观经济形势分析及2008年展望 (54)央企人力资源管理的“蜕变”......................................................周放生张应语（57）推进预算管理与资产管理相结合的实践探索.......................................广东省财政厅（60）规范事业资产管理保障水利事业可持续发展..............................水利部财务经济司（63）全面提高产权管理水平推动中国石化快速发展.....................中国石油化工集团公司（66）规范运作加快整合提高控股上市公司的核心竞争力......中国航空工业第一集团公司（69）强化产权制度建设实现产权规范有序流转.................................国家开发投资公司（71）加强国有资产评估管理确保国有资产有效流转...........................中国电信集团公司（74）上市公司国有股价值变化的信息披露.............................................文宗瑜谭静（77）进一步提高中央企业安全生产管理水平 (80)国有资产管理[月刊]= State assets management /中国人民共和国财政部—2期，2008年.—北京：《国有资产管理》杂志社，(100036) .10.00元ISSN 1002-4247 CN 11-2798索书号：F2/51 馆藏地：西康校区四楼本期目录内容进一步提高中央企业安全生产管理水平.........................................................黄淑和（4）关于中央企业履行社会责任的指导意见 (10)深入贯彻落实科学发展观更好地推进中央企业履行社会责任工作——国务院国资委就《关于中央企业履行社会责任的指导意见》答记者问 (12)完善体制机制和政策措施促进经济发展方式转变.......................................陈柱兵（17）转变国有经济发展方式实现国有资产保值增值.......................................郭复初等（21）国有独资公司董事会的重塑.....................................................................赵大鹏（25）加强沟通交流提高监督质量......................................................张仆杨中静（29）以科学发展理念构建地方国资监管体系的思考.............................................汤光强（31）2008年宏观经济增长趋势展望及政策建议...................................................课题组（34）强化资产安全与效益监管服务交通事业又好又快发展........................交通部财务司（38）积极探索整合资源加强事业单位国有资产处置管理........................湖南省财政厅（41）全面开创国有资产管理工作新局面...................................................河南省财政厅（43）在实践中不断捉高集团公司产权管理水平.................................中国核工业集团公司（46）规范产权管理做好主辅分离助推企业发展........................中国冶金科工集团公司（49）公司治理与企业竞争力...........................................................................周放生（53）中国资产评估协会关于印发《资产评估准则——评估报告》等7项资产评估准则的通知 (55)国有公司治理结构存在的问题及其法律风险防范……………………………………王玉宝（61）加强对外投资及多种经营监管…………………………………………………………张凯（64）盈余管理对企业有益性的探讨…………………………………………………………葛晓红（66）国有企业引进战略投资者的策略……………………………………………屈艳芳郭敏（68）促进我国企业内部控制的建设………………………………………………张宜霞文远怀（71）企业年金信托管理的治理结构研究(一) ……………………………………李连仁周伯岩（74）美英国家政府绩效考评对我国的启示与借鉴…………………………………………聂常虹（76）复印报刊资料·外贸经济、国际贸易[月刊]=Economy of Foreign Trade And Internaional Trade.—第1期，2008年.—北京：中国人民大学书报资料中心，（100086）.11.00元ISSN 1001-3407 CN 11-4289/F索书号：F7/17 馆藏地：西康校区四楼本期目录内容本刊综述2007年国际贸易与我国对外贸易问题综述………………………………………………王亚星(3) 研究与探讨试论新贸易理论之新……………………………………………………………郭界秀朱廷捃(9) 比较优势理论的有效性：基于中国历史数据的检验……………………………………管汉晖(14) 制度分析视角中的贸易开放与经济增长——以投资效率为中心……………………盘为龙(23) 国际贸易、外国直接投资、经济增长对环境质量的影响——基于环境库兹涅茨曲线研究的回顾与展望…………………………胡亮潘厉(30) 贸易政策贸易模式与国家贸易政策差异…………………………………………………………曹吉云(37) 分工演进对贸易政策的影响分析——基于交易成本的考虑…………………张亚斌李峰(44) 中国贸易结构的变化特点、决定要素以及政策建议……………………………………章艳红(50) 专题：进出口贸易二元经济结构、实际汇率错位及其对进出口贸易影响的实证分析……………………吕剑(56) 人民币汇率波动性对中国进出口影响的分析……………………………………谷宇高铁梅(66) 中国对外贸易出口结构存在的问题……………………………………………………魏浩(75) 服务贸易国际知识型服务贸易发展的现状、前景及我国对策分析……………………潘菁刘辉煌(80) 国际服务外包趋势与我国服务外包的发展……………………………………李岳云席庆高(86) 文摘加快我国资本输出和经济国际化的建议......................................................裴长洪(90) 双赢的中美经贸关系缘何被扭曲...............................................................李若谷(91) 索引 (93)英文目录 (96)复印报刊资料·市场营销 [月刊]=Marketing.—第2期，2008年.—北京：中国人民大学书报资料中心，（100086）.6.00元ISSN 1009-1351 CN 11-4288/F索书号：F7/26 馆藏地：西康校区四楼视点营销资讯 (4)特别关注激情燃烧的岁月——行将远去的2007…………………………………………………刘超等(6) 营销创新数字营销上路……………………………………………………………………………岳占仁(12) 手机广告：精准营销的黄金地段…………………………………………………………王浩(15) 论坛营销分析中小企业网上营销安全问题分析...............................................................潘素琼(17) 如何克服电子邮件营销中的广种薄收.........................................................郝洁莹(19) 国产洗发水何以走出迷局? (21)营销人物校长茅理翔………………………………………………………………………………叶丽雅(23) 营销策略博客营销策略……………………………………………………………………………缪启军(26) 企业社会责任标准下的出口营销策略转变……………………………………于晓玲胡日新(29) 品牌管理品牌管理的价值法则……………………………………………………………………辰平(30) 品牌延伸：中国企业需要补课……………………………………………………………曾朝晖(33) 渠道管理渠道模式：一半是火焰一半是海水………………………………………………………钱言(36) 弱势品牌渠道拓展之路…………………………………………………………吴勇毅陈绍华(39) 销售管理销售经理管控销售队伍的四种工具……………………………………………………谢宗云(41) 遭遇难题，见招拆招……………………………………………………………虞坚老树(44) 销售冠军是怎样炼成的——专访苏宁朝阳路店店长刘玉君…………………………齐鹏(47) 成功策划“右手之戒”成就戴比尔斯 (49)拉芳舍一个休闲餐饮王国扩张之谜……………………………………………………王翼(51) 阿尔迪最赚钱的“穷人店”………………………………………………………………杨育谋(53) 个案解读LG巧克力手机得失之间…………………………………………………………………林景新(56) 南京菲亚特：四面楚歌……………………………………………………………………陈宇祥(58) 奥克斯：反思“三大败笔”…………………………………………………………………刘步尘(62)财经科学[月刊]=Finance And Economics—第4期，2007年.—成都：《财经科学》编辑部，（610074）.8.00元ISSN1000-8306 CN51-1104/F索书号： F8/19 馆藏地：本部四楼江宁二楼。

弹性力学专业英语英汉互译词汇弹性力学elasticity弹性理论theory of elasticity均匀应力状态homogeneous state of stress应力不变量stress invariant应变不变量strain invariant应变椭球strain ellipsoid均匀应变状态homogeneous state ofstrain应变协调方程equation of straincompatibility拉梅常量Lame constants各向同性弹性isotropic elasticity旋转圆盘rotating circular disk楔wedge开尔文问题Kelvin problem布西内斯克问题Boussinesq problem艾里应力函数Airy stress function克罗索夫--穆斯赫利Kolosoff- 什维利法Muskhelishvili method基尔霍夫假设Kirchhoff hypothesis板Plate矩形板Rectangular plate圆板Circular plate环板Annular plate波纹板Corrugated plate加劲板Stiffened plate,reinforcedPlate中厚板Plate of moderate thickness 弯[曲]应力函数Stress function of bending 壳Shell扁壳Shallow shell旋转壳Revolutionary shell球壳Spherical shell [圆]柱壳Cylindrical shell锥壳Conical shell环壳Toroidal shell封闭壳Closed shell波纹壳Corrugated shell扭[转]应力函数Stress function of torsion 翘曲函数Warping function半逆解法semi-inverse method瑞利--里茨法Rayleigh-Ritz method 松弛法Relaxation method莱维法Levy method松弛Relaxation量纲分析Dimensional analysis自相似[性] self-similarity影响面Influence surface接触应力Contact stress赫兹理论Hertz theory协调接触Conforming contact滑动接触Sliding contact滚动接触Rolling contact压入Indentation各向异性弹性Anisotropic elasticity颗粒材料Granular material散体力学Mechanics of granular media 热弹性Thermoelasticity超弹性Hyperelasticity粘弹性Viscoelasticity对应原理Correspondence principle褶皱Wrinkle塑性全量理论Total theory of plasticity 滑动Sliding微滑Microslip粗糙度Roughness非线性弹性Nonlinear elasticity大挠度Large deflection突弹跳变snap-through有限变形Finite deformation格林应变Green strain阿尔曼西应变Almansi strain弹性动力学Dynamic elasticity运动方程Equation of motion准静态的Quasi-static气动弹性Aeroelasticity水弹性Hydroelasticity颤振Flutter弹性波Elastic wave简单波Simple wave柱面波Cylindrical wave水平剪切波Horizontal shear wave竖直剪切波Vertical shear wave 体波body wave无旋波Irrotational wave畸变波Distortion wave膨胀波Dilatation wave瑞利波Rayleigh wave等容波Equivoluminal wave勒夫波Love wave界面波Interfacial wave边缘效应edge effect塑性力学Plasticity可成形性Formability金属成形Metal forming耐撞性Crashworthiness结构抗撞毁性Structural crashworthiness 拉拔Drawing破坏机构Collapse mechanism回弹Springback挤压Extrusion冲压Stamping穿透Perforation层裂Spalling塑性理论Theory of plasticity安定[性]理论Shake-down theory运动安定定理kinematic shake-down theorem静力安定定理Static shake-down theorem 率相关理论rate dependent theorem 载荷因子load factor加载准则Loading criterion加载函数Loading function加载面Loading surface塑性加载Plastic loading塑性加载波Plastic loading wave简单加载Simple loading比例加载Proportional loading卸载Unloading卸载波Unloading wave冲击载荷Impulsive load阶跃载荷step load脉冲载荷pulse load极限载荷limit load中性变载nentral loading拉抻失稳instability in tension 加速度波acceleration wave本构方程constitutive equation 完全解complete solution名义应力nominal stress过应力over-stress真应力true stress等效应力equivalent stress流动应力flow stress应力间断stress discontinuity应力空间stress space主应力空间principal stress space静水应力状态hydrostatic state of stress 对数应变logarithmic strain工程应变engineering strain等效应变equivalent strain应变局部化strain localization应变率strain rate应变率敏感性strain rate sensitivity 应变空间strain space有限应变finite strain塑性应变增量plastic strain increment 累积塑性应变accumulated plastic strain 永久变形permanent deformation内变量internal variable应变软化strain-softening理想刚塑性材料rigid-perfectly plasticMaterial刚塑性材料rigid-plastic material理想塑性材料perfectl plastic material 材料稳定性stability of material应变偏张量deviatoric tensor of strain 应力偏张量deviatori tensor of stress 应变球张量spherical tensor of strain 应力球张量spherical tensor of stress 路径相关性path-dependency线性强化linear strain-hardening应变强化strain-hardening随动强化kinematic hardening各向同性强化isotropic hardening强化模量strain-hardening modulus幂强化power hardening塑性极限弯矩plastic limit bendingMoment塑性极限扭矩plastic limit torque弹塑性弯曲elastic-plastic bending弹塑性交界面elastic-plastic interface 弹塑性扭转elastic-plastic torsion粘塑性Viscoplasticity非弹性Inelasticity理想弹塑性材料elastic-perfectly plasticMaterial极限分析limit analysis极限设计limit design极限面limit surface上限定理upper bound theorem上屈服点upper yield point下限定理lower bound theorem下屈服点lower yield point界限定理bound theorem初始屈服面initial yield surface后继屈服面subsequent yield surface屈服面[的]外凸性convexity of yield surface 截面形状因子shape factor of cross-section沙堆比拟sand heap analogy屈服Yield屈服条件yield condition屈服准则yield criterion屈服函数yield function屈服面yield surface塑性势plastic potential 能量吸收装置energy absorbing device 能量耗散率energy absorbing device 塑性动力学dynamic plasticity塑性动力屈曲dynamic plastic buckling 塑性动力响应dynamic plastic response 塑性波plastic wave运动容许场kinematically admissibleField 静力容许场statically admissibleField流动法则flow rule速度间断velocity discontinuity滑移线slip-lines滑移线场slip-lines field移行塑性铰travelling plastic hinge 塑性增量理论incremental theory ofPlasticity米泽斯屈服准则Mises yield criterion 普朗特--罗伊斯关系prandtl- Reuss relation 特雷斯卡屈服准则Tresca yield criterion洛德应力参数Lode stress parameter莱维--米泽斯关系Levy-Mises relation亨基应力方程Hencky stress equation赫艾--韦斯特加德应Haigh-Westergaard 力空间stress space洛德应变参数Lode strain parameter德鲁克公设Drucker postulate盖林格速度方程Geiringer velocityEquation结构力学structural mechanics结构分析structural analysis结构动力学structural dynamics拱Arch三铰拱three-hinged arch抛物线拱parabolic arch圆拱circular arch穹顶Dome空间结构space structure空间桁架space truss雪载[荷] snow load风载[荷] wind load土压力earth pressure地震载荷earthquake loading弹簧支座spring support支座位移support displacement支座沉降support settlement超静定次数degree of indeterminacy机动分析kinematic analysis结点法method of joints截面法method of sections结点力joint forces共轭位移conjugate displacement影响线influence line三弯矩方程three-moment equation单位虚力unit virtual force刚度系数stiffness coefficient柔度系数flexibility coefficient力矩分配moment distribution力矩分配法moment distribution method 力矩再分配moment redistribution分配系数distribution factor矩阵位移法matri displacement method 单元刚度矩阵element stiffness matrix 单元应变矩阵element strain matrix总体坐标global coordinates贝蒂定理Betti theorem高斯--若尔当消去法Gauss-Jordan eliminationMethod屈曲模态buckling mode复合材料力学mechanics of composites复合材料composite material纤维复合材料fibrous composite单向复合材料unidirectional composite泡沫复合材料foamed composite颗粒复合材料particulate composite 层板Laminate夹层板sandwich panel正交层板cross-ply laminate斜交层板angle-ply laminate层片Ply多胞固体cellular solid膨胀Expansion压实Debulk劣化Degradation脱层Delamination脱粘Debond纤维应力fiber stress层应力ply stress层应变ply strain层间应力interlaminar stress比强度specific strength强度折减系数strength reduction factor 强度应力比strength -stress ratio 横向剪切模量transverse shear modulus 横观各向同性transverse isotropy正交各向异Orthotropy剪滞分析shear lag analysis短纤维chopped fiber长纤维continuous fiber纤维方向fiber direction纤维断裂fiber break纤维拔脱fiber pull-out纤维增强fiber reinforcement致密化Densification最小重量设计optimum weight design网格分析法netting analysis混合律rule of mixture失效准则failure criterion蔡--吴失效准则Tsai-W u failure criterion 达格代尔模型Dugdale model断裂力学fracture mechanics概率断裂力学probabilistic fractureMechanics格里菲思理论Griffith theory线弹性断裂力学linear elastic fracturemechanics, LEFM弹塑性断裂力学elastic-plastic fracturemecha-nics, EPFM 断裂Fracture脆性断裂brittle fracture解理断裂cleavage fracture蠕变断裂creep fracture延性断裂ductile fracture晶间断裂inter-granular fracture 准解理断裂quasi-cleavage fracture 穿晶断裂trans-granular fracture裂纹Crack裂缝Flaw缺陷Defect割缝Slit微裂纹Microcrack折裂Kink椭圆裂纹elliptical crack深埋裂纹embedded crack[钱]币状裂纹penny-shape crack预制裂纹Precrack短裂纹short crack表面裂纹surface crack裂纹钝化crack blunting裂纹分叉crack branching裂纹闭合crack closure裂纹前缘crack front裂纹嘴crack mouth裂纹张开角crack opening angle,COA 裂纹张开位移crack opening displacement,COD裂纹阻力crack resistance裂纹面crack surface裂纹尖端crack tip裂尖张角crack tip opening angle,CTOA裂尖张开位移crack tip openingdisplacement, CTOD裂尖奇异场crack tip singularityField裂纹扩展速率crack growth rate稳定裂纹扩展stable crack growth定常裂纹扩展steady crack growth亚临界裂纹扩展subcritical crack growth 裂纹[扩展]减速crack retardation 止裂crack arrest止裂韧度arrest toughness断裂类型fracture mode滑开型sliding mode张开型opening mode撕开型tearing mode复合型mixed mode撕裂Tearing撕裂模量tearing modulus断裂准则fracture criterionJ积分J-integral J阻力曲线J-resistance curve断裂韧度fracture toughness应力强度因子stress intensity factor HRR场Hutchinson-Rice-RosengrenField 守恒积分conservation integral 有效应力张量effective stress tensor 应变能密度strain energy density 能量释放率energy release rate内聚区cohesive zone塑性区plastic zone张拉区stretched zone热影响区heat affected zone, HAZ 延脆转变温度brittle-ductile transitiontempe- rature 剪切带shear band剪切唇shear lip无损检测non-destructive inspection 双边缺口试件double edge notchedspecimen, DEN specimen 单边缺口试件single edge notchedspecimen, SEN specimen 三点弯曲试件three point bendingspecimen, TPB specimen 中心裂纹拉伸试件center cracked tensionspecimen, CCT specimen 中心裂纹板试件center cracked panelspecimen, CCP specimen 紧凑拉伸试件compact tension specimen,CT specimen 大范围屈服large scale yielding小范围攻屈服small scale yielding韦布尔分布Weibull distribution帕里斯公式paris formula空穴化Cavitation应力腐蚀stress corrosion概率风险判定probabilistic riskassessment, PRA 损伤力学damage mechanics损伤Damage连续介质损伤力学continuum damage mechanics 细观损伤力学microscopic damage mechanics 累积损伤accumulated damage脆性损伤brittle damage延性损伤ductile damage宏观损伤macroscopic damage细观损伤microscopic damage微观损伤microscopic damage损伤准则damage criterion损伤演化方程damage evolution equation 损伤软化damage softening损伤强化damage strengthening损伤张量damage tensor损伤阈值damage threshold损伤变量damage variable损伤矢量damage vector损伤区damage zone疲劳Fatigue低周疲劳low cycle fatigue应力疲劳stress fatigue随机疲劳random fatigue蠕变疲劳creep fatigue腐蚀疲劳corrosion fatigue疲劳损伤fatigue damage疲劳失效fatigue failure疲劳断裂fatigue fracture 疲劳裂纹fatigue crack疲劳寿命fatigue life疲劳破坏fatigue rupture疲劳强度fatigue strength 疲劳辉纹fatigue striations 疲劳阈值fatigue threshold 交变载荷alternating load 交变应力alternating stress 应力幅值stress amplitude 应变疲劳strain fatigue应力循环stress cycle应力比stress ratio安全寿命safe life过载效应overloading effect 循环硬化cyclic hardening 循环软化cyclic softening 环境效应environmental effect 裂纹片crack gage裂纹扩展crack growth, crackPropagation裂纹萌生crack initiation 循环比cycle ratio实验应力分析experimental stressAnalysis工作[应变]片active[strain] gage基底材料backing material应力计stress gage零[点]飘移zero shift, zero drift 应变测量strain measurement应变计strain gage应变指示器strain indicator应变花strain rosette应变灵敏度strain sensitivity机械式应变仪mechanical strain gage 直角应变花rectangular rosette引伸仪Extensometer应变遥测telemetering of strain 横向灵敏系数transverse gage factor 横向灵敏度transverse sensitivity 焊接式应变计weldable strain gage平衡电桥balanced bridge粘贴式应变计bonded strain gage粘贴箔式应变计bonded foiled gage粘贴丝式应变计bonded wire gage 桥路平衡bridge balancing电容应变计capacitance strain gage 补偿片compensation technique 补偿技术compensation technique 基准电桥reference bridge电阻应变计resistance strain gage 温度自补偿应变计self-temperaturecompensating gage半导体应变计semiconductor strainGage 集流器slip ring应变放大镜strain amplifier疲劳寿命计fatigue life gage电感应变计inductance [strain] gage 光[测]力学Photomechanics光弹性Photoelasticity光塑性Photoplasticity杨氏条纹Young fringe双折射效应birefrigent effect等位移线contour of equalDisplacement 暗条纹dark fringe条纹倍增fringe multiplication 干涉条纹interference fringe等差线Isochromatic等倾线Isoclinic等和线isopachic应力光学定律stress- optic law主应力迹线Isostatic亮条纹light fringe光程差optical path difference 热光弹性photo-thermo -elasticity 光弹性贴片法photoelastic coatingMethod光弹性夹片法photoelastic sandwichMethod动态光弹性dynamic photo-elasticity 空间滤波spatial filtering空间频率spatial frequency起偏镜Polarizer反射式光弹性仪reflection polariscope残余双折射效应residual birefringentEffect应变条纹值strain fringe value应变光学灵敏度strain-optic sensitivity 应力冻结效应stress freezing effect应力条纹值stress fringe value应力光图stress-optic pattern暂时双折射效应temporary birefringentEffect脉冲全息法pulsed holography透射式光弹性仪transmission polariscope 实时全息干涉法real-time holographicinterfero - metry 网格法grid method全息光弹性法holo-photoelasticity 全息图Hologram全息照相Holograph全息干涉法holographic interferometry 全息云纹法holographic moire technique 全息术Holography全场分析法whole-field analysis散斑干涉法speckle interferometry 散斑Speckle错位散斑干涉法speckle-shearinginterferometry, shearography 散斑图Specklegram白光散斑法white-light speckle method 云纹干涉法moire interferometry [叠栅]云纹moire fringe[叠栅]云纹法moire method 云纹图moire pattern离面云纹法off-plane moire method参考栅reference grating试件栅specimen grating分析栅analyzer grating面内云纹法in-plane moire method脆性涂层法brittle-coating method条带法strip coating method坐标变换transformation ofCoordinates计算结构力学computational structuralmecha-nics加权残量法weighted residual method 有限差分法finite difference method 有限[单]元法finite element method 配点法point collocation里茨法Ritz method广义变分原理generalized variationalPrinciple 最小二乘法least square method胡[海昌]一鹫津原理Hu-Washizu principle赫林格-赖斯纳原理Hellinger-ReissnerPrinciple 修正变分原理modified variationalPrinciple 约束变分原理constrained variationalPrinciple混合法mixed method杂交法hybrid method边界解法boundary solution method有限条法finite strip method半解析法semi-analytical method协调元conforming element非协调元non-conforming element混合元mixed element杂交元hybrid element边界元boundary element 强迫边界条件forced boundary condition 自然边界条件natural boundary condition 离散化Discretization离散系统discrete system连续问题continuous problem广义位移generalized displacement广义载荷generalized load广义应变generalized strain广义应力generalized stress界面变量interface variable节点node, nodal point [单]元Element角节点corner node边节点mid-side node内节点internal node无节点变量nodeless variable 杆元bar element桁架杆元truss element梁元beam element二维元two-dimensional element 一维元one-dimensional element 三维元three-dimensional element 轴对称元axisymmetric element板元plate element壳元shell element厚板元thick plate element三角形元triangular element四边形元quadrilateral element 四面体元tetrahedral element曲线元curved element二次元quadratic element线性元linear element三次元cubic element四次元quartic element等参[数]元isoparametric element超参数元super-parametric element 亚参数元sub-parametric element节点数可变元variable-number-node element 拉格朗日元Lagrange element拉格朗日族Lagrange family巧凑边点元serendipity element巧凑边点族serendipity family无限元infinite element单元分析element analysis单元特性element characteristics 刚度矩阵stiffness matrix几何矩阵geometric matrix等效节点力equivalent nodal force节点位移nodal displacement节点载荷nodal load位移矢量displacement vector载荷矢量load vector质量矩阵mass matrix集总质量矩阵lumped mass matrix相容质量矩阵consistent mass matrix阻尼矩阵damping matrix瑞利阻尼Rayleigh damping刚度矩阵的组集assembly of stiffnessMatrices载荷矢量的组集consistent mass matrix质量矩阵的组集assembly of mass matrices 单元的组集assembly of elements局部坐标系local coordinate system局部坐标local coordinate面积坐标area coordinates体积坐标volume coordinates曲线坐标curvilinear coordinates静凝聚static condensation合同变换contragradient transformation 形状函数shape function试探函数trial function检验函数test function权函数weight function样条函数spline function代用函数substitute function降阶积分reduced integration零能模式zero-energy modeP收敛p-convergenceH收敛h-convergence掺混插值blended interpolation等参数映射isoparametric mapping双线性插值bilinear interpolation小块检验patch test非协调模式incompatible mode节点号node number单元号element number带宽band width带状矩阵banded matrix变带状矩阵profile matrix带宽最小化minimization of band width 波前法frontal method子空间迭代法subspace iteration method 行列式搜索法determinant search method 逐步法step-by-step method纽马克法Newmark威尔逊法Wilson拟牛顿法quasi-Newton method牛顿-拉弗森法Newton-Raphson method 增量法incremental method初应变initial strain初应力initial stress切线刚度矩阵tangent stiffness matrix 割线刚度矩阵secant stiffness matrix 模态叠加法mode superposition method 平衡迭代equilibrium iteration子结构Substructure子结构法substructure technique超单元super-element网格生成mesh generation结构分析程序structural analysis program 前处理pre-processing后处理post-processing网格细化mesh refinement应力光顺stress smoothing组合结构composite structure。