Damage Initiation and Prediction in Composites, Sandwich Structures and Thermal Barrier Coatings最新文献

{"title":"Investigation of Damage in Unidirectional Ceramic Matrix Composites Using a Cohesive-Shear-Lag Model","authors":"B. Yang, S. Mall","doi":"10.1115/imece2001/ad-25300","DOIUrl":"https://doi.org/10.1115/imece2001/ad-25300","url":null,"abstract":"\u0000 The present study develops a cohesive-shear-lag model to analyze the cycling stress-strain behavior of unidirectional fiber-reinforced ceramic matrix composites. The model, as a modification to a classical shear-lag model, takes into account matrix cracking, partial interfacial debonding, and partial breakage of fibers. The statistical nature of partial breakage of fibers is modeled by using a cohesive force law. The validity of the model is demonstrated by investigating stress-strain hysteresis loops of a unidirectional fiber-reinforced ceramic-glass matrix composite, SiC/1723. This example demonstrates the capability of the proposed model to characterize damage and deformation mechanisms of ceramic matrix composites under tension-tension cycling loading. The dominant progressive damage mechanism with cycling in this case is shown to be accumulation of fibers breakage, accompanied by increase in interfacial debonding and smoothening of frictional debonded interface.","PeriodicalId":442756,"journal":{"name":"Damage Initiation and Prediction in Composites, Sandwich Structures and Thermal Barrier Coatings","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117125740","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":"Compressive Instabilities in Braided Textile Composites","authors":"Shu Ching Quek, A. Waas, V. Agaram, K. Shahwan","doi":"10.1115/imece2001/ad-25306","DOIUrl":"https://doi.org/10.1115/imece2001/ad-25306","url":null,"abstract":"\u0000 This paper discusses the results of a finite element (FE) based study of the compressive instabilities of braided glass fiber composites. The micromodel was based on a 2-unitcell size 3-D FE model. Computational tests were carried out to first determine the elastic moduli of the system. Once the computational model was validated with experimental data for the elastic moduli, the compressive response of the micromodel was established using the RIKS method option available in the ABAQUS commercial FE code. The present approach is different from that reported in the literature where classical methods based on the technique of homogenization is used to model the elastic and inelastic response of braided composites. In the present work, explicit account of the braid microstructure (geometry and packing) and the inelastic properties of the matrix are accounted for via the use of the FE method. The macromechanical data pertaining to the braided composites were obtained through traditional means. Tensile tests were performed on the composites through the usage of ASTM D 3039 standard to obtain the macroscopic orthotropic moduli and response. For each test, 3 samples were used to ensure accuracy and the average data is reported in this paper. A separate test was conducted to obtain the in-situ matrix properties of the glass braided composites. The computational model provides a means to assess the compressive strength of braided composites and its dependence on various microstructural parameters. It also serves as a tool to assess the most significant parameter that affects compressive strength. Furthermore, the model is useful to understand the response of braided composites under multiaxial loads.","PeriodicalId":442756,"journal":{"name":"Damage Initiation and Prediction in Composites, Sandwich Structures and Thermal Barrier Coatings","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128014756","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":"Damage Assessment in Thermal Barrier Coatings Using Thermal Wave Imaging Technique","authors":"X. Chen, G. Newaz, X. Han","doi":"10.1115/imece2001/ad-25323","DOIUrl":"https://doi.org/10.1115/imece2001/ad-25323","url":null,"abstract":"\u0000 Thermal wave imaging (TWI) was used to investigate damage processes in electron beam-physical vapor deposited (EB-PVD) ZrO2-8% wt.%Y2O3 thermal barrier coatings (TBCs) during thermal cycling. TWI is a non-destructive and non-contact evaluation method. Small interfacial decohesions from manufacturing were captured by TWI after only two thermal cycles, but the decohesions did not grow with thermal cycling. No delamination was found in TBC specimens until failure, while surface temperature profiles of TWI indicated increases of thermal wave signal amplitude with thermal cycles. Local interfacial damage formed due to high thermal residual stresses during thermal cycling and induced thermal contact resistance in the TBCs, which resulted in the increases of thermal wave signal amplitude. The results of TWI confirmed the progressive damage evolution in TBCs observed by microscopy. The buckling propagation and spallation process were monitored by TWI.","PeriodicalId":442756,"journal":{"name":"Damage Initiation and Prediction in Composites, Sandwich Structures and Thermal Barrier Coatings","volume":"509 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134261889","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":"Fiber Pullout Characteristics Under Dynamic Loading Conditions","authors":"N. Sridhar, Qingda Yang, B. Cox","doi":"10.1115/imece2001/ad-25305","DOIUrl":"https://doi.org/10.1115/imece2001/ad-25305","url":null,"abstract":"\u0000 Inertial effects in the mechanism of fiber pullout during dynamic propagation of a bridged crack are critically examined. By reposing simple shear lag models of pullout as problems of dynamic wave propagation, the effect of frictional coupling between the fiber and the matrix is accounted for in a fairly straightforward way. The frictional sliding between the fiber and the matrix is described by a constant interfacial friction stress, the sign of which depends on the relative particle velocity of the fiber and the matrix. Analytical solutions are derived when the load or bridging traction on the fiber in the crack plane increases linearly in time. The results show that when the wave speed of the matrix exceeds a critical value, the frictional fiber pullout behavior transitions from a state of pure slip to a state where part of the sliding zone slips and the remaining sticks. When stick occurs, the fiber and the matrix within the stick zone slide past each other with an interfacial shear stress less than the shear stress required for slipping. Regions of slip and stick propagate and increase with time and influence the time-dependent relationship between the crack opening displacement and the bridging tractions.","PeriodicalId":442756,"journal":{"name":"Damage Initiation and Prediction in Composites, Sandwich Structures and Thermal Barrier Coatings","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127278272","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":"A Study of Crack Growth in Sandwich Composite Beams","authors":"S. El-Sayed, S. Sridharan","doi":"10.1115/imece2001/ad-25311","DOIUrl":"https://doi.org/10.1115/imece2001/ad-25311","url":null,"abstract":"\u0000 The paper proposes models to track the face-core interfacial delamination growth and crack kinking into the sandwich core, respectively. The models consist in interposing a cohesive layer along a pre-existing delamination or an identified plane of crack propagation. The former, designated as CLD (cohesive layer delamination model) is investigated first in detail using an example of a restrained beam specimen. The Influence of the key parameters of the model, viz. the thickness of the cohesive layer and the strength and stiffness of the cohesive layer material, have been studied. It is found that the model is fairly robust and is not sensitive to changes in parameters other than the critical strain energy release rate. The second model is a highly simplified one, but it is nevertheless a comprehensive model which can track the crack path by identifying crack planes in various elements using a maximum tensile stress criterion. This is designated as CLDK model as it deal with delamination and crack kinking — whichever is the preferred mode of fracture. The models are constructed ensuring that the crack opening is controlled by the critical value of strain energy release rate in mode I fracture. Experimental results of two sandwich specimens, viz. bottom restrained beams with 0° and −10° tilt angle respectively were used for comparison. The results indicate that the both the models are able to capture the initiation and track the growth of the interfacial delamination. The CLDK model tracks the crack kinking into the core, and its subsequent return to the facesheet-core interface.","PeriodicalId":442756,"journal":{"name":"Damage Initiation and Prediction in Composites, Sandwich Structures and Thermal Barrier Coatings","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116482187","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":"Modeling Intersonic Crack Propagation in Fiber Reinforced Composites With Contact/Cohesive Laws","authors":"S. Dwivedi, H. Espinosa","doi":"10.1115/imece2001/ad-25313","DOIUrl":"https://doi.org/10.1115/imece2001/ad-25313","url":null,"abstract":"\u0000 Dynamic crack propagation in an unidirectional Carbon/Epoxy composite is studied through finite element analyses in total Lagrangian co-ordinates. A finite deformation anisotropic visco-plastic model is used to describe the constitutive response of the composite. Crack initiation and propagation is simulated by embedding zero thickness interface element along the possible crack path. An irreversible cohesive law is used to describe the evolution of normal and shear tractions as a function of displacement jumps. The compressive response prior to interface failure is analyzed using contact impenetrability conditions. The failure of the first interface element at the pre-notch tip models crack initiation. Crack propagation is modeled through consecutive failure of interface elements. Dynamic crack propagation phenomena are studied in terms of crack initiation time, crack speed, mode I and mode II displacement jumps and tractions associated with the failure of interface elements, effective plastic strain at the crack tip and path independent integral J′. Analyses are first carried out for the dynamic crack propagation along bi-material interfaces. The results obtained from present analyses agree well with literature data. Detailed analyses are carried out for a pre-notched unidirectional Carbon/Epoxy composite material. The impact velocity in the analyses is an imposed velocity over an assumed impact region and remains constant throughout the analysis. Analyses are carried out at impact velocities of 5, 10, 20, 30 and 40 m/s, assuming the crack wake is frictionless. Moreover, analyses at impact velocities of 30 and 40 m/s are also carried out with a friction coefficient of 0.5 along the crack surfaces. The analyses established intersonic crack speed in the fiber reinforced composite material. Intersonic crack propagation for the impact velocities of 40 m/s is 400% of the shear wave speed and 87% of the longitudinal wave speed. Detailed discussion is given on the features of sub-sonic and intersonic crack propagation in Carbon/Epoxy composite materials. It is shown that the friction coefficient along the crack surface plays an important role by smearing the discontinuous field that develops behind the crack tip and by reducing crack speed in the intersonic regime. The analyses show that the contour integral J′ computed at near field contours are path independent and can serve as a parameter for characterizing intersonic crack propagation.","PeriodicalId":442756,"journal":{"name":"Damage Initiation and Prediction in Composites, Sandwich Structures and Thermal Barrier Coatings","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127489586","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 Failure Behavior of Recycled Aluminum Reinforced Composites","authors":"Brian M. June, R. Pidaparti, H. El-Mounayri","doi":"10.1115/imece2001/ad-25309","DOIUrl":"https://doi.org/10.1115/imece2001/ad-25309","url":null,"abstract":"\u0000 In order to effectively use the recycled aluminum cans, many applications of aluminum are being explored. One of the most obvious applications is to reinforce with wood or others, to form sandwich composites. The goal of the proposed work is to conduct the research to develop constructional products, which would permit reuse of aluminum cans instead of destroying the structure by melting or trashing. With that goal in mind, our specific objective of this study is to evaluate the stiffness and failure behavior of recycled aluminum reinforced composites under three-point bending for use in composite industries. Composite specimens containing the end sections of the can sandwiched between top and bottom layers of wood are investigated. The results of bending stiffness and failure behavior of sandwich composite panels obtained from the three-point bending tests are presented and discussed.","PeriodicalId":442756,"journal":{"name":"Damage Initiation and Prediction in Composites, Sandwich Structures and Thermal Barrier Coatings","volume":"186 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124932401","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":"Tensile and Fracture Characterization of PVC Foam Cores","authors":"G. M. Viana, L. Carlsson","doi":"10.1115/imece2001/ad-25320","DOIUrl":"https://doi.org/10.1115/imece2001/ad-25320","url":null,"abstract":"\u0000 Mechanical behavior in tension and fracture toughness of cross-linked PVC foams have been characterized. Young’s modulus, yield strength and fracture toughness data were compared to micro-structural relations derived for open and closed-cell foams. The failure process and stress strain response were indicative of brittle material behavior.","PeriodicalId":442756,"journal":{"name":"Damage Initiation and Prediction in Composites, Sandwich Structures and Thermal Barrier Coatings","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131662024","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":"Design Study of Composite Sandwich Truck Tank Using a High-Order Sandwich Theory Approach","authors":"O. Thomsen, J. Vinson","doi":"10.1115/imece2001/ad-25316","DOIUrl":"https://doi.org/10.1115/imece2001/ad-25316","url":null,"abstract":"\u0000 The paper presents a preliminary design study on the structural response of a boxy composite sandwich truck tank subjected to hydraulic head loading. The design study is approximate in that it considers a 2-D cross section of the composite sandwich truck tank. The design study is performed using a high-order sandwich theory formulation in which the elastic responses of the face laminates are accounted for individually, and in which the transverse flexibility of the sandwich core is included. Thus the model allows the sandwich panel thickness of the truck tank to change during deformation, and the model accounts for the existence of transverse normal stresses in the core material in the sandwich panel sections. The paper includes a presentation of the high-order formulation for the curved sandwich panel parts of the composite sandwich truck tank sections, as well as a brief description of the numerical solution of the complete set of system equations with corresponding boundary conditions. The paper is concluded with a numerical study, showing the characteristic features of the elastic response of a composite sandwich truck tank section subjected to hydraulic head loading.","PeriodicalId":442756,"journal":{"name":"Damage Initiation and Prediction in Composites, Sandwich Structures and Thermal Barrier Coatings","volume":"302 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133916154","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":"An Analytical Study of Post-Buckling of Debonded One-Dimensional Sandwich Plates","authors":"B. Sankar, Màrten Sylwan","doi":"10.1115/imece2001/ad-25318","DOIUrl":"https://doi.org/10.1115/imece2001/ad-25318","url":null,"abstract":"\u0000 An analytical method is developed to study the problem of one-dimensional sandwich plates containing debonded face-sheets and subjected to in-plane compressive loads. The non-linear governing equations for the sandwich plate are solved to obtain a relation between the boundary forces and displacements in a matrix form as in the finite element method. The debonded sandwich plate is divided into four elements. The element stiffness matrices are assembled to obtain the global stiffness matrix, and the global equations are solved to obtain the displacements. The results include load/end-shortening relations. The method is found to be very efficient and accurate, and can be used to study the progressive damage of debonded sandwich plates under in-plane compressive loads.","PeriodicalId":442756,"journal":{"name":"Damage Initiation and Prediction in Composites, Sandwich Structures and Thermal Barrier Coatings","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132547190","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}