Composites Engineering最新文献_第2页

Composite skin-stiffener debond analyses using fracture mechanics approach with shell elements 基于壳单元断裂力学方法的复合材料蒙皮加筋剥离分析

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(94)00097-S

J.T. Wang, I.S. Raju, D.W. Sleight

{"title":"Composite skin-stiffener debond analyses using fracture mechanics approach with shell elements","authors":"J.T. Wang, I.S. Raju, D.W. Sleight","doi":"10.1016/0961-9526(94)00097-S","DOIUrl":"10.1016/0961-9526(94)00097-S","url":null,"abstract":"<div><p>Fracture mechanics analyses of composite skin-stiffener debond configurations using shell elements are presented. Two types of debond configurations are studied: a flange skin strip debond configuration and a skin-stiffener debond configuration. The flange-skin strip configuration examines debond growth perpendicular to the stiffener while the skin-stiffener configuration examines debond growth parallel to the stiffener. Four-node and 9-node shell elements are used to model both debond configurations. The stiffener flange and skin are modeled as two different layers of elements whose translational degrees-of-freedom, in the bonded portion, of the corresponding flange and skin nodes are constrained to be identical. Strain energy release rate formulae are presented for both 4-node and 9-node element models based on the virtual crack closure technique (VCCT). In addition, average values of the strain energy release rates are calculated using a gradient method. The VCCT formulae and the gradient method are used to compute the strain energy release rates (<em>G</em>-values) for both debond configurations. The <em>G</em>-values predicted by these methods are compared with those predicted by plane-strain and 3D finite element analyses. Excellent correlation is obtained among all the analysis results, thus helping to validate the VCCT formulae derived for the 4- and 9-node shell elements.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 3","pages":"Pages 277-296"},"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)00097-S","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91245189","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: 26

In-situ crack propagation in pressureless sintered fiber reinforced composites 无压烧结纤维增强复合材料中的原位裂纹扩展

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)00050-W

C.P. Ostertag

引用次数: 2

In-situ ultrasonic surface wave assessment of mechanical fatigue damage accumulation in metal matrix composites 金属基复合材料机械疲劳损伤累积的原位超声表面波评价

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)00082-X

Patrick T. MacLellan, David A. Stubbs, Prasanna Karpur

{"title":"In-situ ultrasonic surface wave assessment of mechanical fatigue damage accumulation in metal matrix composites","authors":"Patrick T. MacLellan, David A. Stubbs, Prasanna Karpur","doi":"10.1016/0961-9526(95)00082-X","DOIUrl":"10.1016/0961-9526(95)00082-X","url":null,"abstract":"<div><p>This study demonstrates that an <em>in-situ</em> nondestructive, ultrasonic surface wave technique can successfully detect the onset and extent of matrix cracking fatigue damage in a titanium metal matrix composite (MMC). A quasi-isotropic [0/±45/90]<sub>s</sub>SCS-6/Timetal® 21S MMC material was used for room temperature fatigue tests and the resultant matrix cracking damage was ultrasonically monitored <em>in situ</em> as a function of cycle count. Damage accumulation in the material was successfully correlated with decreases in ultrasonic pitch catch amplitude and verified through the use of immersion ultrasonic C-scans and metallographic techniques. Damage initiation and progression was tracked through the use of complementary nondestructive and destructive techniques. The <em>in-situ</em> surface wave data show that the higher the fatigue stress level, the more quickly damage occurs; conversely, the lower the stress level, the slower the damage initiation. The <em>in-situ</em> surface wave technique proved to be more sensitive to the accumulating damage than standard load-displacement modulus measurements. The surface wave technique also indicated a change in material properties after only one fatigue cycle. The data acquired show that a better understanding of damage initiation and accumulation can be gained using the <em>in-situ</em> surface wave technique in comparison to current load-displacement modulus measurements.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 12","pages":"Pages 1413-1422"},"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)00082-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85038072","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: 2

Impact response of single-lap composite joints 单搭接复合材料接头的冲击响应

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)00003-6

Su-Seng Pang, Chihdar Yang, Yi Zhao

引用次数: 33

Acoustic emission sources in a cross-ply laminated plate 交叉层合板中的声发射源

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(94)00072-H

E.Rhian Green

引用次数: 17

The effects of mechanical damage in a glass fibre/epoxy composite on the absorption rate 机械损伤对玻璃纤维/环氧树脂复合材料吸收率的影响

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(94)00014-Z

C. Suri, D. Perreux

引用次数: 47

A coupled higher-order theory for functionally graded composites with partial homogenization 部分均质化功能梯度复合材料的耦合高阶理论

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)00032-I

Jacob Aboudi , Marek-Jerzy Pindera, Steven M. Arnold

{"title":"A coupled higher-order theory for functionally graded composites with partial homogenization","authors":"Jacob Aboudi , Marek-Jerzy Pindera, Steven M. Arnold","doi":"10.1016/0961-9526(95)00032-I","DOIUrl":"10.1016/0961-9526(95)00032-I","url":null,"abstract":"<div><p>In a recent series of papers, the authors have shown that the currently employed micromechanics approach applied to functionally graded materials, based on the concept of a representative volume element (RVE) assumed to exist at every point within the material, may produce erroneous results in the presence of macroscopically nonuniform material properties and large field variable gradients. As a result, a new higher-order theory for functionally graded materials has been developed that explicitly couples the microstructural and macrostructural effects, thereby providing both a rational methodology for analyzing the response of this new class of materials and a means for evaluating the uncoupled RVE-based micromechanics approach. Herein, the new theory is further generalized by combining it with a partial homogenization scheme applied along the nonfunctionally graded directions, while preserving the elements of micro-macrostructural coupling along the graded direction. As a practical consequence, composite plates functionally graded in the through-thickness direction and subjected to a thermal gradient along the same direction can now be analyzed in the presence of imposed average normal stresses in the nongraded inplane directions. Examples dealing with such composite plates are presented that illustrate the effect of partial homogenization on the internal stress fields and inplane moment resultants.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 7","pages":"Pages 771-792"},"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)00032-I","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87040220","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: 35

Thermal analysis of a functionally graded material subject to a thermal gradient using the boundary element method 应用边界元法对受热梯度作用的功能梯度材料进行热分析

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)00030-Q

Robert K. Goldberg, Dale A. Hopkins

{"title":"Thermal analysis of a functionally graded material subject to a thermal gradient using the boundary element method","authors":"Robert K. Goldberg, Dale A. Hopkins","doi":"10.1016/0961-9526(95)00030-Q","DOIUrl":"10.1016/0961-9526(95)00030-Q","url":null,"abstract":"<div><p>The boundary element method is utilized in this study to conduct thermal analyses of functionally graded composites, materials in which the internal microstructure of properties are explicitly tailored in order to obtain an optimal response, on the micromechanical (constituent) scale. A unique feature of the boundary element formulations used here is the use of circular shape functions to convert the two-dimensional integrations of the composite fibers to one-dimensional integrations. Using the computer code BEST-CMS, the through the thickness temperature profiles are computed for a representative material with varying numbers of fibers and fiber spacing in the thickness direction. The computed temperature profiles are compared to those obtained using an alternative analytical theory which explicitly couples the heterogeneous microstructure to the global analysis. The boundary element results compared favorably to the analytical calculations, with discrepancies that are explainable based on the boundary element formulation. The results serve both to demonstrate the ability of the boundary element method to analyze these types of materials, and to verify the accuracy of the analytical theory.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 7","pages":"Pages 793-806"},"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)00030-Q","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87301311","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: 25

List of reviewers 审稿人名单

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)90000-4

引用次数: 0

Ultrasonic and vibration methods for the characterization of pultruded composites 拉挤复合材料的超声和振动表征方法

Composites Engineering Pub Date : 1995-01-01 DOI: 10.1016/0961-9526(95)00074-W

Krishnan Balasubramaniam, Satyanarayana Alluri, Praveen Nidumolu, P.Raju Mantena, James G. Vaughan, Murthy Kowsika

{"title":"Ultrasonic and vibration methods for the characterization of pultruded composites","authors":"Krishnan Balasubramaniam, Satyanarayana Alluri, Praveen Nidumolu, P.Raju Mantena, James G. Vaughan, Murthy Kowsika","doi":"10.1016/0961-9526(95)00074-W","DOIUrl":"10.1016/0961-9526(95)00074-W","url":null,"abstract":"<div><p>Characterization of unidirectional fiber reinforced glass/epoxy pultruded composites using ultrasonics (high frequency, 1-5 MHz) and the impulse-frequency response vibration (intermediate frequency, 50-100 Hz) technique, is demonstrated here. This paper compares the response of both of these non-destructive test techniques to the changes in the pultrusion process variables and to the indeed contaminants introduced during manufacturing. The ultrasonic methods use multi-mode techniques of wave velocity and attenuation measurements to measure the viscoelastic constants of the pultruded composite while the vibration technique provides the dynamic flexural modulus and loss factor (damping) measurements. Quasi-destructive assays were also performed using a low frequency (1-50 Hz) Dynamic Mechanical Analyser (DMA) to verify the state of pultruded samples with induced contaminants (simulated porosity and interfacial debonding) and the results compared with the non-destructive measurements. Mathematical models to describe the influence of porosity and debonding agents on the material properties were derived based on statistical regression analysis procedures. Results indicate that the peak damping value of the tan δ curve obtained from the DMA is a sensitive parameter to detect abnormalities in the finished product. The ultrasonic velocity and dynamic flexural modulus measurements provide useful information on the stiffness characteristics while the attention and loss factor can be related to the anomaly-sensitive damping properties of the material.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 12","pages":"Pages 1433-1451"},"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)00074-W","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88812795","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: 15