• Title/Summary/Keyword: Bimaterial

Search Result 49, Processing Time 0.033 seconds

Three-dimensional numerical simulation and cracking analysis of fiber-reinforced cement-based composites

  • Huang, Jun;Huang, Peiyan
    • Computers and Concrete
    • /
    • v.8 no.3
    • /
    • pp.327-341
    • /
    • 2011
  • Three-dimensional graphic objects created by MATLAB are exported to the AUTOCAD program through the MATLAB handle functions. The imported SAT format files are used to produce the finite element mesh for MSC.PATRAN. Based on the Monte-Carlo random sample principle, the material heterogeneity of cement composites with randomly distributed fibers is described by the WEIBULL distribution function. In this paper, a concept called "soft region" including micro-defects, micro-voids, etc. is put forward for the simulation of crack propagation in fiber-reinforced cement composites. The performance of the numerical model is demonstrated by several examples involving crack initiation and growth in the composites under three-dimensional stress conditions: tensile loading; compressive loading and crack growth along a bimaterial interface.

Four Point Bending Test for Adhesion Testing of Packaging Strictures: A Review

  • Mahan, Kenny;Han, Bongtae
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.21 no.4
    • /
    • pp.33-39
    • /
    • 2014
  • To establish the reliability of a packaging structures, adhesion testing of key interfaces is a critical task. Due to the material mismatch, the interface may be prone to delamination failure due to conditions during the manufacturing of the product or just from the day-to-day use. To assess the reliability of the interface adhesion strength testing can be performed during the design phase of the product. One test method of interest is the four-point bending (4PB) adhesion strength test method. This test method has been implemented in a variety of situations to evaluate the adhesion strength of interfaces in bimaterial structures to the interfaces within thin film multilayer stacks. This article presents a review of the 4PB adhesion strength testing method and key implementations of the technique in regards to semiconductor packaging.

Boundary Element Evaluation of Stress Intensity Factor for Interface Crack in Elastic and Viscoelastic Composite Materials (경계요소법에 의한 탄성-점탄성 복합구조체의 계면균열 해석)

  • 이상순;김정규;황종근
    • Computational Structural Engineering
    • /
    • v.9 no.1
    • /
    • pp.85-91
    • /
    • 1996
  • The focus of the present work is on the computation of the stress intensity factor for the crack at the elastic-viscoelastic bimaterial interface. First, the stress intensity factor for an interface crack in dissimilar elastic and viscoelastic materials is dervied by applying the correspondence principle to associated elastic expression. Then the time-domain boundary element analysis is performed to calculate the stress intensity factor. Numerical results show that the proposed method is very useful for the analysis of the interface crack in elastic and viscoelastic materials.

  • PDF

A Study for Mutual Interference Between Circular Inclusion and Crack in Finite-Width Plate by Boundary Element Method (경계요소법에 의한 유한폭 판재내의 원형 함유물과 균열의 상호간섭에 대한 연구)

  • 박성완
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.18 no.6
    • /
    • pp.1474-1482
    • /
    • 1994
  • In order to study the influence of a circular inclusion on a stress field neat a crack tip, mutual interference of a crack and the circular inclusion is analyzed by using the two dimensional boundary element method program made for the analysis of a bimaterial inclusion. The stress intensity factor of an inclusion which has small stiffness is a little greater than that of large stiffness in the near-by crack tip, and similar values tends to appear for distant crack tips. A line crack shows the repetition phenomena which caused by stress mutual interference depending on the radius and stiffness of an inclusion, and the repetition phenomena becoms weak in the inclusion which has large stiffness. Stress mutual interference shows repetition phenomena after extension of a line crack by the length of the radius of the inclusion which has small stiffness.

A Study on the Development of Stress Optic Law Considering Residual Stress in Photoelastic Experiment(II) -Application of Stress Optic Law Considering of Residual Sterss- (잔류응력을 고려한 광탄성실험의 광응력법칙 개발에 관한 연구 (2) -잔류응력을 고려한 광응력법칙의 응용-)

  • 서재국;황재석;최선호
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.19 no.8
    • /
    • pp.1810-1821
    • /
    • 1995
  • Photoelastic experiment has been used to analyze stress of structure and stress in the vicinity of crack tip etc.. Model experiment such as photoelastic experiment has been restricted by problem of residual stress in the photoelastic model material. They are generated by molding, cutting and time effects etc.. They produce some errors in the results of photoelastic experiment data. In this paper, stress optic law considering residual stress already developed by authors was applied to the stress concentration problem and fracture mechanics. Although the specimen was bad with residual stress, we could obtain good results by using the stress optic law considering residual stress. It was found that the stress optic law of photoelastic experiment could be applied to the stress analysis of bimaterial.

Meshfree Collocation Method on the Interface between Bimaterial Media (무요소 콜로케이션법을 이용한 이종재료 계면해석)

  • Kim Hyo-Jin;Yoon Young-Chol;Kim Dong-Jo;Lee Sang-Ho
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2006.04a
    • /
    • pp.365-372
    • /
    • 2006
  • A new meshfree formulation is developed for material discontinuity problems. A local interfacial jump function which is defined as hyperplane function is embedded in the meshless approximation and the approximation accurately models functions with jumps in the displacement and the derivative fields. Diffuse derivative technique copes with difficulty due to complexity of derivative computation of meshfree approximation. Collocation method with diffuse derivative accelerates computing speed for numerical solution. By solving inclusion and composite material problems, the robustness and effectiveness of the method are verified.

  • PDF

Fracture mechanics analysis of a crack in a weld of dissimilar steels using the J-ingegral (J-적분을 이용한 이종강재 용접접합부 균열의 파괴역학적 해석)

  • 이진형;장경호
    • Proceedings of the KWS Conference
    • /
    • 2004.05a
    • /
    • pp.264-266
    • /
    • 2004
  • for the kぉ mechanics analysis of a crack in a weld of dissimilar steels, residual stress analysis and fracture analysis must be performed simultaneously. The standard definition of the J-integral leads to a path dependent value in the presence of a residual stress field. And unlike cracks in homogeneous materials, a bimaterial interface crack always induces both opening and shearing modes of stress in the vicinity of the crack tip. Therefore, it is necessary to develope a path independent J-integral definition for a crack in a residual stress field generated by welding of dissimilar steels. This paper addresses the modification of the Rice-J-integral to produce a path independent J-integral when residual stresses due to welding of dissimilar steels and external forces are present. The residual stress problem is heated as an initial stain problem and the J-integral proposed for this class of problems is used And a program which can evaluate the 1-integral for a crack in a weld of dissimialr steels is developed using proposed J-integral definition.

  • PDF

Analyses of Stress Intensity Factors for Slant Crack Emanation from Circular Inclusion by Boundary Element Method (경계요소법에 의한 원형함유물에서 파생되는 경사균열의 응력확대계수 해석)

  • Park, Sung-Oan;Hwang, Soon-Won
    • Journal of the Korean Society of Manufacturing Technology Engineers
    • /
    • v.7 no.5
    • /
    • pp.72-84
    • /
    • 1998
  • In order ot study the influence of a circular inclusion on a stress field near a crack tip, mutual interference of a slant crack and the circular inclusion is analyzed of a bimaterial inclusion. As the crack emanates at the equivalent slant crack angle the correction factors FⅠ and FⅡ for the inclusion wit small Young's modulus were found to decrease as the inclusion radius increased. The correction factors for inclusion with large Young's modulus increase as the inclusion radius increases at the equivalent radius of the inclusion, the correction factors decrease as the slant crack angle increases for the aspect ratio $\frac{c}{W}$ = 0.1 irrespective of the Young's modulus. For $\frac{c}{W}$ greater than 0.2, they increase as the slant crack angle increases. There is no influence of stress mutual interfce after crack emanates beyond the inclusion radius.

  • PDF

A Study on the Fatigue Crack Growth Characteristics for the Weldment of Carbon steel-Stainless steel (탄소강-스테인리스강 용접부의 피로균열진전 특성에 관한 연구)

  • 권재도;김우현;김길수;박중철;배용탁;김중형
    • Journal of Welding and Joining
    • /
    • v.16 no.4
    • /
    • pp.47-54
    • /
    • 1998
  • Various equipments in plants are welded with two different materials and it is required to investigate the effects of fatigue crack propagation on the neighborhood of a welded portion. The characteristics of fatigue crack growth in the base metal of carbon and stainless steel, in the carbon and stainless steel sides located in the neighborhood of welded portion (carbon/stainless steel), respectively and welded portion, are investigated. The results show that the crack growth in the welded portion (carbon/stainless steel) is an average value of the crack growths in the carbon and stainless steel respectively located in the neighborhood of the welded portion. It is found that the crack growth in the welded portion is not significantly different from those in the carbon and stainless steel sides. Hence it can be concluded that the structure welded with two different materials wold not impede the integrity based on the fatigue crack growth.

  • PDF

A Simple Analysis to Obtain a Singularity near a Crack Perpendicular to Bimaterial Interface by Using 8-node Isoparametric Element (8절점 등매개 요소를 이용하여 이종재료 접합면에 수직인 크랙의 특이성 표시를 위한 간편해석법)

  • Won-Kyun Lim;Sang-Chul Kim
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.29 no.2
    • /
    • pp.73-78
    • /
    • 1992
  • Numerical method by Abdi et al. for obtaining a stress singularity near a crack perpendicular to the interface between two elastic materials is reviewed. More efficient and simple method to obtain crack singularity by shifting a mid-side node of 8-node isoparametric element is presented. It is observed that the present analysis provides increased accuracy for the expression of the opening displacement and the determination of the optimal position of the mid-side node for a wide range of material properties.

  • PDF