Composites Engineering最新文献

{"title":"Non-linear numerical study of the single-fiber fragmentation test. Part I: Test mechanics","authors":"H. Ho,&nbsp;L.T. Drzal","doi":"10.1016/0961-9526(95)00065-U","DOIUrl":"10.1016/0961-9526(95)00065-U","url":null,"abstract":"<div><p>A non-linear finite element method is used to investigate the mechanics of the test procedure of single-fiber fragmentation test of AS4/Epon 828 composite containing an interphase. Stress transfer between the fiber and matrix for fragments created at different matrix strain state is evaluated. The ineffective fiber length was found to vary with the matrix strain state. It is found that the stress transfer and local stress fields remain unchanged for constant, linear and power-law interphase property gradients as long as the average interphase properties are the same. Causes and effects of debonding and debond propagation are examined through the evaluation of the stress fields near the fiber breaks. The effect of thermal residual stresses is examined. Stress transfer for fragments of shorter length than the critical length is studied. Physical meaning of the critical length is discussed.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 10","pages":"Pages 1231-1244"},"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)00065-U","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74210684","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}

{"title":"Interlaminar stress analysis of composites: Layer-wise shell finite elements including transverse strains","authors":"Yavuz Basar,&nbsp;Yunhe Ding","doi":"10.1016/0961-9526(95)00020-N","DOIUrl":"10.1016/0961-9526(95)00020-N","url":null,"abstract":"<div><p>Theoretical fundamentals for a 2D layer-wise laminate theory including the transverse shear and transverse normal strains are presented which provide a compromise between the continuum theory and the single-layer laminate theories. Four-node isoparametric assumed strain layer-wise shell elements are developed which can be applied to interlaminar stress analysis of composite laminates and simulation of stress singularities due to concentrated loading, freeedge effects, etc. Numerical examples are given to demonstrate the ability and accuracy of the numerical models proposed.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 5","pages":"Pages 485-499"},"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)00020-N","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83414547","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}

{"title":"Determination of fiber-matrix interphase effective elastic moduli from ultrasonic phase velocity and attenuation data","authors":"S.I. Rokhlin,&nbsp;Y.C. Chu,&nbsp;W. Huang","doi":"10.1016/0961-9526(95)00038-O","DOIUrl":"10.1016/0961-9526(95)00038-O","url":null,"abstract":"<div><p>This paper discusses two potential ultrasonic methods for characterization of fiber-matrix interphases in composites: measurement of phase velocity and attenuation. The characterization procedures of these two methods, including different implementations using analytical or numerical models, are reviewed with emphasis on the applicability of these methods. Examples of ultrasonic characterization of interphases in ceramic and intermetallic matrix composites are given and the relation between the measured and actual interphase moduli is discussed. Application of these techniques for interfacial damage assessment is also demonstrated, including characterization of oxidation damage in ceramic matrix composites and fatigue damage in metal matrix composites. The experimental results show that degradation of the interphasial layer significantly affects ultrasonic wave attenuation and velocity. Thus both methods are very useful for assessment of interfacial damage.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 6","pages":"Pages 713-733"},"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)00038-O","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84756287","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}

{"title":"Ultrasonic technique to measure stiffness coefficients of CMC and its implications on characterizing material degradation","authors":"Manohar Bashyam","doi":"10.1016/0961-9526(95)00011-B","DOIUrl":"10.1016/0961-9526(95)00011-B","url":null,"abstract":"<div><p>The main objectives of this research are to characterize the fiber content of composite materials using nondestructive methods, to characterize fiber, matrix and fiber-matrix interface degradation in a quantitative manner and to predict the elastic behavior of the composite material using ultrasonic techniques.</p><p>We can achieve the above objectives if we can experimentally compute the stiffness matrix that can be derived by either destructive or nondestructive methods. We focus on nondestructive methods to generate the stiffness matrix of ceramic matrix composites (CMC) using ultrasonic techniques. The use of ultrasonic waves in measurement of the dynamic elastic moduli of solids is well known (Truell <em>et al.</em> (1969). <em>Ultrasonic Methods in Solid State Physics</em>, Academic Press). If the density and elastic anisotropy of a solid are specified then the elastic moduli can be deduced from wave speed measurements of shear and longitudinal waves propagating in particular directions in the solid. The relations between wave speed and moduli follow from the theory of small amplitude elastic wave propagating in an anisotropic solid (Musgrave (1970). <em>Crystal Acoustics</em>, Holden-Day).</p><p>In this paper, we will discuss the experiments conducted on three CMC (CAS-Nicalon) unidirectional blocks with varying fiber fractions estimated at 31, 42 and 51%, using ultrasonic longitudinal, transverse and surface acoustic wave (SAW) velocities. Techniques to improve and automate data acquisition are discussed along with the experimental results.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 6","pages":"Pages 735-742"},"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)00011-B","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73808811","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}

{"title":"Single-shot explosive welding technique for the fabrication of multilayered metal base composites: effect of welding parameters leading to optimum bonding condition","authors":"K. Hokamoto ,&nbsp;A. Chiba ,&nbsp;M. Fujita ,&nbsp;T. Izuma","doi":"10.1016/0961-9526(95)00059-V","DOIUrl":"10.1016/0961-9526(95)00059-V","url":null,"abstract":"<div><p>Multilayered metal base composites, mainly reinforced with steel sheets, were fabricated using the single-shot explosive welding technique. Plate velocity change during the collision of multilayered plates within small stand-off distances were analyzed using a one-dimensional finite-difference calculation, and the explosive welding parameters required for good bonding were investigated. Wavy interfaces, which suggest good bonding, were found in the case where properties, such as density, strength and melting point, of the bonded materials were not so different, but excess melting, poor bonding and planar interfacial structure were observed when the properties of the materials used were considerably different. In the case where properties of the materials were fairly different, the weldable condition for good bonding was restricted. In this investigation, the way to regulate the explosive welding parameters for good bonding and the welding mechanisms were discussed, and the mechanical properties of the composites measured by tensile tests were investigated based on the rule of mixtures.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 8","pages":"Pages 1069-1079"},"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)00059-V","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84697090","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}

{"title":"Laser effects on the dynamic response of laminated composites","authors":"J. K. Chen, A. Perea, F. Allahdadi","doi":"10.1016/0961-9526(95)00049-S","DOIUrl":"https://doi.org/10.1016/0961-9526(95)00049-S","url":null,"abstract":"","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"1 1","pages":"1135-1147"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75207060","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}

{"title":"The effects of laminated composite patch with different stacking sequences on bonded repair","authors":"Ching-Hwei Chue,&nbsp;Thomas Jin-Chee Liu","doi":"10.1016/0961-9526(95)90715-N","DOIUrl":"10.1016/0961-9526(95)90715-N","url":null,"abstract":"<div><p>This paper discusses the effect of laminated composite patch with different stacking sequences on repairing an inclined central cracked plate under biaxial loads. By means of the finite element method and the strain energy density theory, the results show that the optimal ply orientations of the patch are the three directions 90° and ± 45° related to the crack direction. Also, the use of different stacking sequences for the patch does not affect the energy distribution near the crack tip significantly.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 2","pages":"Pages 223-230"},"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)90715-N","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85232856","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}

{"title":"Bending of long cross-ply composite circular cylinders","authors":"Edmundo Corona,&nbsp;Ashok Rodrigues","doi":"10.1016/0961-9526(95)90711-J","DOIUrl":"10.1016/0961-9526(95)90711-J","url":null,"abstract":"<div><p>The response of long, thin-walled, cross-ply composite tubes subjected to pure bending was studied analytically. The formulation includes three parts: pre-buckling response, material failure and bifurcation buckling. The pre-buckling response is analyzed using nonlinear kinematics to accommodate the ovalization of the cross-section. The formulation is based on the principle of virtual work and is used to generate a numerical solution procedure. The Tsai-Wu failure criterion is used to detect material failure in the pre-buckling response. The maximum stress criterion was also considered for comparison. Finally, the buckling analysis considers the possibility of bifurcation into modes containing periodic displacements along the axis of the tube. The tubes are assumed to be geometrically perfect and free of residual stress. Three materials-AS3501 graphite-epoxy, Kevlar 49-epoxy, and E-glass-epoxy-and three diameter-to-thickness ratios-50, 100 and 400-are considered. The moment-curvature response of the tubes is non-linear due to the ovalization of the cross-section (Brazier effect) which induces a limit moment instability. Either material failure or bifurcation buckling always occurs prior to the limit moment in the cases considered. Little difference was observed between the failure loads predicted by the Tsai-Wu and the maximum stress criteria. Tubes with plies of circumferentially oriented fibers in the outermost and innermost positions in the wall proved superior in strength compared with the other cases considered.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 2","pages":"Pages 163-179, 181-182"},"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)90711-J","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81028320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NITINOL-reinforced plates: Part I. Thermal characteristics","authors":"J. Ro,&nbsp;A. Baz","doi":"10.1016/0961-9526(95)93980-A","DOIUrl":"10.1016/0961-9526(95)93980-A","url":null,"abstract":"<div><p>The static and dynamic characteristics of NITINOL-reinforced composite plates are influenced primarily by the temperature distribution inside the composite matrix. Such distribution arises from the electrical heating of NITINOL fibers embedded along the neutral plane of these composite plates. When temperatures are developed above the martensite transformation temperature of the NITINOL fiber, the elastic modulus of the fibers increases approximately fourfold and significant phase recovery forces are generated. Such thermal activation of the NITINOL fibers increases the elastic energy of the fibers and enchances the stiffness of the plates, provided that the phase recovery forces are high enough to compensate for the loss of the modulus of elasticity of the composite and counterbalance the generated thermal loads. Understanding the interaction between the thermal, static and dynamic characteristics of the NITINOL-reinforced plates is essential to tailoring the performance of these plates to match changes in the operating conditions. Such an interaction is influenced primarily by the temperature distribution inside the plates during the activation and de-activation of the NITINOL fibers. In this study, a thermal finite element model is developed to determine steady-state and transient temperature distributions inside NITINOL-reinforced composite plates resulting from different activation strategies of the NITINOL fibers. The theoretical predictions are compared with experimental measurements in order to validate the thermal finite element model. The resulting temperature distribution can be used to determine an average modulus of elasticity of the composite. The average temperature rise above ambient can also be used to compute the axial thermal loading on the composite plate. Such predictions are utilized in computing the static and dynamic characteristics of NITINOL-reinforced plates which are presented in Parts II and III of this paper, respectively.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 1","pages":"Pages 61-75"},"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)93980-A","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73579686","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}

{"title":"Impact-fatigue behavior of composite tube/metal end fitting bonded joints","authors":"B.W. Barber,&nbsp;D.W. Radford","doi":"10.1016/0961-9526(95)00002-5","DOIUrl":"10.1016/0961-9526(95)00002-5","url":null,"abstract":"&lt;div&gt;&lt;p&gt;The relatively high specific strengths and moduli of advanced composite materials make them an attractive option for use in high speed industrial equipment. Hence, a potential market exists for integrating composites into existing machinery to replace critical metallic components. An application of such is the replacement of a high speed reciprocating steel bodymaker ram with one fabricated from a filament wound carbon fiber tube with bonded steel end fittings. Due to the dynamic forces which are inherent in the operation of high speed machinery, components are often subjected to impact, fatigue, and combined high cycle impact-fatigue. The behavior of composites as well as adhesives subjected to either impact or fatigue is well established. However, the combined impact-fatigue behavior of adhesive joints between filament wound carbon-fiber reinforced epoxy tubes and steel end fittings has not been investigated and is the focus of this study.&lt;/p&gt;&lt;p&gt;An impact-fatigue testing machine was designed and fabricated specifically for these tests. The impact pulses generated by the machine closely resemble those of a conventional drop weight impact test machine. In addition, the impact-fatigue machine is capable of completing high cycle impact-fatigue tests (10&lt;sup&gt;6&lt;/sup&gt; impacts) within a relatively short period of time by operating in excess of 10 impacts per second. Tests were performed at several impact load levels ranging from 15% to as much as 40% of the joint &lt;span&gt;&lt;math&gt;&lt;mtext&gt;U&lt;/mtext&gt;&lt;/math&gt;&lt;/span&gt;ltimate &lt;span&gt;&lt;math&gt;&lt;mtext&gt;S&lt;/mtext&gt;&lt;/math&gt;&lt;/span&gt;tatic &lt;span&gt;&lt;math&gt;&lt;mtext&gt;C&lt;/mtext&gt;&lt;/math&gt;&lt;/span&gt;ompressive &lt;span&gt;&lt;math&gt;&lt;mtext&gt;F&lt;/mtext&gt;&lt;/math&gt;&lt;/span&gt;ailure -&lt;span&gt;&lt;math&gt;&lt;mtext&gt;L&lt;/mtext&gt;&lt;/math&gt;&lt;/span&gt;oad. These impact load levels were monitored throughout the specimen lifetime. Furthermore, three bondline thicknesses were investigated to attain an initial indication of the sensitivity to bondline thickness variation.&lt;/p&gt;&lt;p&gt;Results indicate that the specimens exhibit an initial plateau region for a number of cycles during which time no decrease in load carrying capacity is measured. After a critical number of impacts, damage becomes apparent as the sample is no longer capable of maintaining the initial load. At this point, these constant-displacement tests show a load drop and a corresponding compliance change is noted as the sample begins to show less resistance to impact. Post-impact compression test results also show this drop in strength and modulus. Further, the percentage of the &lt;span&gt;&lt;math&gt;&lt;mtext&gt;U&lt;/mtext&gt;&lt;/math&gt;&lt;/span&gt;ltimate &lt;span&gt;&lt;math&gt;&lt;mtext&gt;S&lt;/mtext&gt;&lt;/math&gt;&lt;/span&gt;tatic -&lt;span&gt;&lt;math&gt;&lt;mtext&gt;C&lt;/mtext&gt;&lt;/math&gt;&lt;/span&gt;ompressive -&lt;span&gt;&lt;math&gt;&lt;mtext&gt;F&lt;/mtext&gt;&lt;/math&gt;&lt;/span&gt;ailure Load being applied dynamically determines the length of the plateau as well as the rate of degradation. Thus, the determination of the performance of composite tube/metal end fitting bonded joints using this impact-fatigue test approach gives information critical fo","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 8","pages":"Pages 995-1003, 1005-1009"},"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)00002-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79520908","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}