Composites Engineering最新文献_第9页

Analyses of fibre push-out test based on the fracture mechanics approach 基于断裂力学方法的纤维推出试验分析

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)00053-P

Li-Min Zhou, Yiu-Wing Mai, Lin Ye

{"title":"Analyses of fibre push-out test based on the fracture mechanics approach","authors":"Li-Min Zhou, Yiu-Wing Mai, Lin Ye","doi":"10.1016/0961-9526(95)00053-P","DOIUrl":"10.1016/0961-9526(95)00053-P","url":null,"abstract":"<div><p>Theoretical analyses based on the concept of fracture mechanics have been developed to evaluate the interfacial properties of ceramic matrix composites in single fibre push-out tests. Two different fibre push-out models, i.e. single fibre-matrix model and three-cylinder model, were presented for different specimen geometries. The interfacial debonding and fibre push-out stresses were analyzed similar to the fibre pull-out test (<em>Zhou et al., J. Mater. Sci.</em> 27, 3155–3166 and <strong>29</strong>, 5541–5550). In the three-cylinder model, the push-out of a single fibre in a specimen with multiple fibres was treated as a three-cylinder composite in which a fibre is located at the centre of a coaxial cylindrical shell of the matrix matrerial which in turn is surrounded by a transversely isotropic elastic material with elastic properties of the bulk composite. The radius of the matrix cylinder in this case is related to the volume fraction of the fibre which significantly affects the behaviour of interfacial debonding and fibre push-out. A simple methodology is presented on the basis of these analyses to determine the interfacial properties, including interfacial fracture toughness <em>G</em><sub>ic</sub>, residual clamping stress <em>q</em><sub>0</sub> and coefficient of interfacial friction μ, from the experimental results of maximum debond stress <span><math><mtext>σ</mtext><msub><mi></mi><mn><mtext>d</mtext></mn></msub><mtext>∗</mtext></math></span> (or initial debond stress <em>σ</em><sub>d</sub><sup>0</sup>) and initial frictional push-out stress <em>σ</em><sub>fr</sub> measured in a fibre push-out test. The effects of the fibre volume fraction, the transversely isotropic property and the Poisson expansion of the fibre are all considered in the analyses.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 10","pages":"Pages 1199-1219"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(95)00053-P","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81949404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 27

Determination of interfacial properties from observations of progressive fiber debonding and pullout 从纤维逐渐脱粘和拉出的观察中测定界面特性

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)00009-C

Roger D. Cordes, Isaac M. Daniel

{"title":"Determination of interfacial properties from observations of progressive fiber debonding and pullout","authors":"Roger D. Cordes, Isaac M. Daniel","doi":"10.1016/0961-9526(95)00009-C","DOIUrl":"10.1016/0961-9526(95)00009-C","url":null,"abstract":"<div><p>The characterization of the fiber/matrix interface or interphase region is important in accurately modeling the behavior of composites. Pushout and pullout testing on single fibers are the two primary methods for examining interfacial properties such as the coefficient of friction, residual stresses, interfacial strength or toughness, and the fiber roughness. In this study, single fiber pullout tests were performed on silicon carbide fibers (SCS-2) embedded in a barium borosilicate glass matrix. The samples were made by first passing the silicon carbide fibers through a flame and then sandwiching them between two pieces of glass. The sandwich was then heated in air for 75 min at 850°C under slight pressure. Relations between the length of the debond and the applied load (during progressive debonding) and between the embedded length and the applied load during pullout were determined from the pullout tests. The transparency of the glass allowed the propagation of the debond crack to be observed using an optical microscope. The roughness of the interface caused significant wearing during pullout.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 6","pages":"Pages 633-648"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(95)00009-C","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90825719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 14

Improving fracture resistance of laminar textile composites by third direction reinforcement 用三向增强法提高层状纺织复合材料的抗断裂性能

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)00089-6

S. Adanur, Y. Tsao, C. W. Tam

引用次数: 9

Improving fracture resistance of laminar textile composites by third direction reinforcement 用三向增强法提高层状纺织复合材料的抗断裂性能

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)00089-6

S. Adanur, Y.P. Tsao, C.W. Tam

引用次数: 9

Effects of interphases on the transverse stress-strain behavior in unidirectional fiber reinforced metal matrix composites 界面相对单向纤维增强金属基复合材料横向应力-应变行为的影响

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)00013-D

David R. Veazie, Jianmin Qu

{"title":"Effects of interphases on the transverse stress-strain behavior in unidirectional fiber reinforced metal matrix composites","authors":"David R. Veazie, Jianmin Qu","doi":"10.1016/0961-9526(95)00013-D","DOIUrl":"10.1016/0961-9526(95)00013-D","url":null,"abstract":"<div><p>In the context of continuum mechanics, the interfaces between the fiber and matrix are often assumed to be perfect. However, in many fiber reinforced composites, the bond between the fibers and the matrix material is not of the perfect kind that can be modeled by a continuity of traction and displacements across the fiber-matrix interface. Instead, the bond is affected across a thin interfacial zone, an interphase, which has distinct properties from the fiber and matrix. In this paper, a framework has been established to characterize the effects of distinct interphases in the study of fiber reinforced composites. On the basis of this framework, a rigorous analysis has been carried out for the transverse normal loading of a unidirectional fiber reinforced composite. It is assumed that such an interphase is created deliberately by coating the fibers with a third phase material. By the use of the finite element method, a numerical analysis for a basic cell provides results for the micromechanical fields of stresses and the macromechanical properties of the composite, with and without partial interphase failure. In addition, an analytical estimation scheme to predict the transverse effective stress-strain relation is developed by using a modified Mori-Tanaka method. Satisfactory agreement between the analytical estimates and the numerical solutions is found.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 6","pages":"Pages 597-610"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(95)00013-D","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85645524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 20

Stress-free edge influence on thermal fatigue damage in an SCS-6/Ti-24A1-11Nb composite 无应力边缘对SCS-6/Ti-24A1-11Nb复合材料热疲劳损伤的影响

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(94)00102-F

William C. Revelos, Joseph L. Kroupa

{"title":"Stress-free edge influence on thermal fatigue damage in an SCS-6/Ti-24A1-11Nb composite","authors":"William C. Revelos, Joseph L. Kroupa","doi":"10.1016/0961-9526(94)00102-F","DOIUrl":"10.1016/0961-9526(94)00102-F","url":null,"abstract":"<div><p>Unidirectionally reinforced [90]<sub>8</sub> specimens of an SCS-6/Ti-24A1-11Nb (at.%) composite (35 vol.% fiber) in three different gage-section widths were thermally cycled in air between 150 and 815°C for 500 cycles. During thermal cycling, matrix cracks initiated at the composite surface and propagated into the composite normal to the fiber direction. However, near the stress-free edges of all specimens, a region void of cracks existed which extended an average of 5.4 fiber diameters into the width of the composite. This cracking pattern was attributed to the presence of a thermally induced cyclic tensile residual stress which dissipates to zero near the stress-free edge of the composite. The finite element method was employed to determine how the fiber-matrix interface shear resistance influences the development of these residual stresses. Using coulomb friction as a measure of shear resistance, the matrix residual stresses in the fiber direction had a peak value of 500 MPa. A frictional coefficient range of 0.18–0.22 was found to give between 95% and 99% of this peak value within 5.4 fiber diameters from the edge. Thermal cycling of the model between 150 and 815°C provided evidence that the resultant cyclic stresses were tensile in nature and were suggested as the probable cause of the periodic surface cracks. The reduction in post-cycling transverse strength with increasing gage-section width indicated that the smaller-width specimens exhibited less damage per cross-sectional area than the wider specimens.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 4","pages":"Pages 347-351, 353-361"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(94)00102-F","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88031843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

NITINOL-reinforced plates: Part II. Static and buckling characteristics 镍钛醇增强板:第二部分。静态和屈曲特性

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)93981-Z

J. Ro, A. Baz

{"title":"NITINOL-reinforced plates: Part II. Static and buckling characteristics","authors":"J. Ro, A. Baz","doi":"10.1016/0961-9526(95)93981-Z","DOIUrl":"10.1016/0961-9526(95)93981-Z","url":null,"abstract":"<div><p>The static and buckling characteristics of flexible fiberglass NITINOL-reinforced composite plates are controlled by activating optimal sets of NITINOL fibers embedded along the midplane of these plates. The NITINOL fibers are pre-tensioned and activated to generate significant phase recovery forces in order to increase the membrane strain energy which in turn increases the critical buckling load of the NITINOL-reinforced plates. With such control capabilites, the plates can be manufactured from light weight sections without compromising their elastic stability. This feature is invaluable in building light weight structures that have high resistance to failure due to buckling. The NITINOL fibers are trained to memorize the shape of the unbuckled plate and when the plate is deflected under the action of external compressive loads, the controller activates the NITINOL fibers by heating them above their transformation temperature. The generated phase recovery forces bring the plate back to its memorized undeflected position. A finite element model of NITINOL-reinforced plates is developed to describe the interaction between the external loads, operating conditions and the geometrical and physical parameters of the composite plate and the NITINOL fibers. This model predicts the critical buckling loads of NITINOL-reinforced plates. The predicted loads are compared with results available in the literature for symmetrically isotropic, orthotropic and anisotropic laminates. The mathematical model described in this paper provides an invaluable means of predicting realistic performance of NITINOL-reinforced composites.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 1","pages":"Pages 77-90"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(95)93981-Z","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80078407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 40

Fiber-matrix interface study of carbon-carbon composites using ultrasonics and acoustic microscopy 利用超声和声学显微镜研究碳-碳复合材料的纤维-基体界面

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)00008-B

C.Eric Yen, Bernhard R. Tittmann

{"title":"Fiber-matrix interface study of carbon-carbon composites using ultrasonics and acoustic microscopy","authors":"C.Eric Yen, Bernhard R. Tittmann","doi":"10.1016/0961-9526(95)00008-B","DOIUrl":"10.1016/0961-9526(95)00008-B","url":null,"abstract":"<div><p>This paper addresses the use of ultrasonics in the characterization of carbon-carbon (C/C) composites during pyrolysis in three ways: (1) to monitor <em>in situ</em> the evolution of the fiber-matrix interface by acoustic emission (AE); (2) to determine the effect of microcracks on the composites by measuring the elastic stiffness; (3) to examine the evolution of microstructure as a function of temperature by scanning acoustic microscope (SAM). Analysis of the anisotropic wave propagation in C/C composites is presented for two cases: (1) the determination of local mechanical properties by the use of bulk waves; (2) the determination of global mechanical properties by the use of guided plate waves. Other measurements, such as those of mass spectrometry, bulk porosity, weight loss and cross-ply thickness shrinkage were carried out to support the ultrasonic measurements.</p><p>AE results show that the majority of the cracks were found to form in the temperature range from 400 to 600°C. This observation was supported by the measurements of porosity, weight loss, thickness shrinkage, mass spectrometry, and surface morphology with SAM. The stiffness measurements showed a decrease of 72.21 GPa for in-plane stiffness along the fiber direction and only 5.06 GPa for out-of-plane stiffness. The greater decrease in the in-plane stiffness is attributed to the large number of transverse cracks which make the composite “acoustically soft”. The analysis of the dispersion curves for plate waves suggests the viability of monitoring the global mechanical properties of C/C composites during the first carbonization.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 6","pages":"Pages 649-661"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(95)00008-B","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72639462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Ultrasonic characterization of the fiber-matrix interphase/interface for mechanics of continuous fiber reinforced metal matrix and ceramic matrix composites 连续纤维增强金属基与陶瓷基复合材料界面力学的超声表征

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)00010-K

Prasanna Karpur, Theodore E. Matikas, S. Krishnamurthy

{"title":"Ultrasonic characterization of the fiber-matrix interphase/interface for mechanics of continuous fiber reinforced metal matrix and ceramic matrix composites","authors":"Prasanna Karpur, Theodore E. Matikas, S. Krishnamurthy","doi":"10.1016/0961-9526(95)00010-K","DOIUrl":"10.1016/0961-9526(95)00010-K","url":null,"abstract":"<div><p>This paper presents a novel approach to evaluate the elastic properties and the behavior of the interphase region formed by a chemical reaction between the matrix and the fiber materials in metal matrix and ceramic matrix composites. Contrary to the traditional approach which does not allow any relative displacement at the interface without fracture, this paper considers elastic deformation of the interphase zone between the matrix and the fiber by replacing the zone by an “equivalent elastic interface”. The elastic behavior of the equivalent elastic interface describes the local elastic rigidity and deformation of the interphase zone and can be quantified by a mechanics parameter called “shear stiffness coefficient” which is proportional to the ratio of the shear modulus to the local thickness of the interphase material. This paper also outlines an ultrasonic reflectivity modeling that can be used for the experimental measurement of the interfacial shear stiffness coefficient along the length of an embedded fiber. Further, an experimental method of measurement of the shear stiffness coefficient is presented and experimentally measured values are tabulated. The significance of the quantification of such a parameter is that the elastic property of the interface obtained can be used as a common basis among material scientists designing and developing the composite systems, and groups studying material behavior for life prediction. Also, the parameter can be used by production engineers to assure that the designed properties of the composite are being achieved, and by the end users to ensure that the designed and produced properties are being retained in use.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 6","pages":"Pages 697-711"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(95)00010-K","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75189367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

NITINOL-reinforced plates: Part III. Dynamic characteristics 镍钛诺增强板:第三部分。动态特性

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)93982-2

J. Ro, A. Baz

{"title":"NITINOL-reinforced plates: Part III. Dynamic characteristics","authors":"J. Ro, A. Baz","doi":"10.1016/0961-9526(95)93982-2","DOIUrl":"10.1016/0961-9526(95)93982-2","url":null,"abstract":"<div><p>The dynamic characteristics of NITINOL-reinforced composite plates are controlled by heating sets of NITINOL fibers embedded inside these plates. The activation of the shape memory effect of these NITINOL fibers increases the elastic energy, enchances the stiffness of the composite plates and modifies their modal characteristics. One of the objectives of the resulting modal modification is to shift the modes of vibration of the plates away from the excitation frequencies in order to avoid undesirable resonances. In this way, the modal characteristics can be tailored in response to the external disturbances acting on the plates. The classical finite element approach is used to form the equations of motion of the assembly of NITINOL-reinforced plate elements and the appropriate boundary conditions are then applied. The solution of the eigenvalues of the resulting homogeneous equations gives the natural frequencies of the NITINOLreinforced plate as influenced by the properties of the composite matrix and the NITINOL fibers. It is important to note that these properties are influenced by the temperature distribution inside the composite plate which is developed by virtue of activating and de-activating the NITINOL fibers. Emphasis is placed on the effect of intentional electrical heating of a selected subset of the NITINOL fibers on the overall dynamics of the plates. The effect of the associated thermal energy propagating through the composite on the unintentional thermal activation of additional subsets of the NITINOL fibers is accounted for. Such an effect is not only significant, but also essential to the thorough understanding of the operation of the NITINOL-reinforced plates.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 1","pages":"Pages 91-97, 99-106"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(95)93982-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73671760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 28