Recent Advances in Solids/Structures and Application of Metallic Materials最新文献

{"title":"Mechanical Properties of Polycrystalline Lamellar TiAl-Intermetallics","authors":"S. Schlögl, E. A. Werner, F. Fischer","doi":"10.1115/imece1996-0160","DOIUrl":"https://doi.org/10.1115/imece1996-0160","url":null,"abstract":"\u0000 TiAl-intermetallics with a fully lamellar microstructure seem to be potential candidates for industrial applications. In this paper a micromechanical study is presented focussing on the room temperature plastic flow behavior of polycrystalline lamellar intermetallics under uniaxial loading conditions. In this course plastic flow of single lamellar grains is analyzed by a crystal plasticity approach which takes into account crystallographic slip and deformation twinning. The dependence of the flow behavior on the angle between the lamellae and the loading direction reveals the highly anisotropic nature of the crystals. Then plastic flow in various lamellar polycrystals is modelled. The highest ductility (low work hardenability and high elongation to fracture) is predicted for microstructures containing grains of low strength arranged in continuous grain clusters.","PeriodicalId":407468,"journal":{"name":"Recent Advances in Solids/Structures and Application of Metallic Materials","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130435268","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 and Simulation of Crack Initiation and Growth in Particulate Composites","authors":"Y. Kwon, J. H. Lee, C. Liu","doi":"10.1115/1.2842311","DOIUrl":"https://doi.org/10.1115/1.2842311","url":null,"abstract":"\u0000 A micro/macromechanical approach was used to model and simulate crack initiation and crack propagation in particulate composite structures. The approach used both the micromechanical and macromechanical analyses in tandem. The micromechanical analysis was based on a simplified micromechanical model and damage mechanics at the micro-level, and the macromechanical analysis utilized the finite element method. In using these methods, crack initiation and growth in a general shape of composite structure were investigated with an efficient computational effort. It was assumed that a crack initiates and/or propagates when localized damage is saturated. As a result, the crack length was assumed to be the size of the saturated damage zone. Matrix crack initiation and propagation at circular notch tips were simulated using this approach. Modeling and simulation were also conducted for cases of non-uniform particle distribution in particulate composite structures. Predicted results showed a good agreement with the experimental data.","PeriodicalId":407468,"journal":{"name":"Recent Advances in Solids/Structures and Application of Metallic Materials","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124667444","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":"Bifurcation and Postbuckling Response of Asymmetric Laminated Columns","authors":"A. Vinogradov, W. Derrick, A. Keck","doi":"10.1115/imece1996-0149","DOIUrl":"https://doi.org/10.1115/imece1996-0149","url":null,"abstract":"\u0000 The paper concerns the buckling and postbuckling response of laminated composite columns with arbitrary material lay-ups. The objective of the study is to examine the joint effects of bending-stretching couplings and initial imperfections on the nonlinear buckling behavior of irregular asymmetric laminates. In the paper, the analysis is focused on the nonlinear buckling problem of eccentrically loaded composite columns composed of n isotropic elastic layers. The response of such columns is examined over a range of structural parameters leading to several conclusions regarding the typical buckling characteristics and optimization of asymmetric laminates.","PeriodicalId":407468,"journal":{"name":"Recent Advances in Solids/Structures and Application of Metallic Materials","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128288077","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":"Stiffness Enhancement of Metallic Beam-Like Components","authors":"E. Rivin, Panchal Pankach","doi":"10.1115/imece1996-0153","DOIUrl":"https://doi.org/10.1115/imece1996-0153","url":null,"abstract":"\u0000 Stiffness is an important design criterion. Since bending deformations of structural components are much larger than tension/compression deformations under comparable loads, enhancement of bending stiffness of beam-like components is an important problem. Conventional techniques for stiffness enhancement (beefing up, optimization, use of high Young’s modulus materials) frequently do not achieve the desired results. The paper describes a novel approach to bending stiffness enhancement based on the inverse buckling effect. The beam is composed of the structural external member having an axial hole which is plugged and filled with a fusible metal alloy expanding during solidification thus stretching the external member and enhancing its stiffness. Experimental study resulting in 40% increase in bending stiffness is described.","PeriodicalId":407468,"journal":{"name":"Recent Advances in Solids/Structures and Application of Metallic Materials","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114204654","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":"Applications of Two-State M-Integral to a Triple Junction Vertex Under Thermal Loading","authors":"S. Im, I. Jeon","doi":"10.1115/imece1996-0144","DOIUrl":"https://doi.org/10.1115/imece1996-0144","url":null,"abstract":"\u0000 The two-state M-integral, which is derived from the M-integral and is applicable for two elastic states, is applied for computing an intensity of a singular near-tip field around the vertex of a triple junction of three different materials under thermal loading, often encountered in electronic packaging. Numerically we verify that a simple auxiliary field associated with every eigenfunction for the composite wedge under consideration exists in the form of the conjugate solution in the sense of the M-integral. The auxiliary field is then employed for superposition with the elastic field under consideration, and the associated two-state M-integral is computed via the domain integral technique. This enables us to extract the intensity for a leading singular eigenfunction. The proposed computational scheme enjoys the efficiency and simplicity in that the near-field information for a singular elastic boundary layer is extracted from the domain integral representation without resort to singular finite elements for the wedge vertex.","PeriodicalId":407468,"journal":{"name":"Recent Advances in Solids/Structures and Application of Metallic Materials","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115659044","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":"Stress Analysis and Design Improvement for Commercial Vehicle Frames With Bolted Joints","authors":"Y. Kim, Jin Gon Kim, S. Choi","doi":"10.1115/imece1996-0150","DOIUrl":"https://doi.org/10.1115/imece1996-0150","url":null,"abstract":"\u0000 Structural failures such as crack initiation often arise near the bolted parts of the side member and trunnion bracket of some commercial vehicles. To prevent these problems, a designer should be able to analyze with confidence the bolted joints of the structures, and this will require a reliable and practically simple bolted joint modelling technique. Once the modelling technique is established with experimental verification, the key design varibles must be identified in order to alleviate the level of the stress concentration near the problem region.\u0000 The purpose of this paper consists of two major parts: the establishment of a simple and practical bolted joint modelling technique and the determination of the key design variables for design improvement. Utilizing the established joint modelling technique, a number of finite element calculations are carried out for the analysis of the system consisting of the vehicle side member and trunnion bracket. The numerical results have indicated that the torsional rigidity of the frame cross section and the trunnion bracket size are critical design variables.","PeriodicalId":407468,"journal":{"name":"Recent Advances in Solids/Structures and Application of Metallic Materials","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133938553","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 Optimization Technique Using the Finite Element Method and Orthogonal Arrays","authors":"Stuart H. Young","doi":"10.1115/imece1996-0147","DOIUrl":"https://doi.org/10.1115/imece1996-0147","url":null,"abstract":"\u0000 The objective of this research was to develop an optimization technique that can be used interactively by design engineers to approach an optimal design with minimal computational effort. The technique can be applied to both continuous and discrete values of design variables. A large number of design variables can be also considered.\u0000 In order to meet the objective, an optimization procedure was developed by coupling the finite element analysis (FEA) to the orthogonal array experimentation technique, because FEA is a common analysis tool for design engineers. From the results of the FEA and an orthogonal array, an average Jacobian matrix was constructed that showed the average overall sensitivity of the design variables. These sensitivities were then used to optimize the design parameters. The process could then be repeated at the discretion of the engineer until he was satisfied with the design. In general, the designer can predict and control the number of FEA calculations before an optimization process so that he can plan a budget and time for an optimal design.\u0000 Some examples of structural optimization with truss structures with continuous and discrete values of design variables were studied using the technique developed in this paper. Their optimal solutions were found with small numbers of iterations.","PeriodicalId":407468,"journal":{"name":"Recent Advances in Solids/Structures and Application of Metallic Materials","volume":"29 22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129681296","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 Initiation and Propagation in Metal Laminates","authors":"R. Riddle, D. Lesuer, C. Syn","doi":"10.1115/imece1996-0157","DOIUrl":"https://doi.org/10.1115/imece1996-0157","url":null,"abstract":"\u0000 The metal laminates proposed here for use in aircraft structures consist of aluminum alloy interlayers between aluminum alloy based metal matrix composite (MMC) plates reinforced with silicon carbide particles. The properties of the laminates are to be tailored for applications in jet engine fan containment and in various wing and auxiliary support structures. One important mechanical property of the metal laminate is fracture toughness.\u0000 This composite metal structure is designed to have enhanced ductile fracture properties as a result of the plastic formability of the aluminum layers and increased strength and stiffness due to the layers of the metal matrix composite.\u0000 The enhanced fracture properties of the metal laminates are measured by fracture toughness specimens of several designs. Of particular interest is the optimum thickness of the ductile interlayer to optimize the fracture properties, but have the least effect on the strength and the stiffness. Specimen designs have been chosen which should allow measured properties of the specimen deformation and failure to be translated into predictions of component strength in actual aerospace applications.\u0000 One mode of crack growth which increases fracture toughness and damage resistance in applications of interest is extensive delamination between the ductile interlayer and the MMC plates.\u0000 The total area of delamination is increased by the tendency of metal laminates to have damage initiate at the lobes of contours of effective plastic strain which are significantly off-axis from the plane of Mode I or tensile mode opening crack growth. This off-axis damage increases the delaminated area and is a factor in forcing the crack to reinitiate at a new location in the next MMC plate.\u0000 Experimental evidence for this phenomena is presented, along with finite element calculations which quantify and explain enhanced fracture values. The progressive damage is modeled using tie-break slidelines with critical strains to failure chosen with the help of elastic-plastic fracture mechanics calculations.","PeriodicalId":407468,"journal":{"name":"Recent Advances in Solids/Structures and Application of Metallic Materials","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131042618","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}