This paper proposes a digital image-based analysis of porous ceramics to study numerically the correlation between the heterogeneous microstructure and the macroscopic properties and behaviors. The homogenization method is the core technique of the multi-scale stress analysis with the help of the finite element method. The microstructure modeling is carried out practically by the digital image-based technique and the high resolution X-ray CT machine. The morphology analysis is very useful for the understanding of the heterogeneity and the microstructure modeling. The quantitative evaluation of the calculated microscopic stress distribution is very important, and therefore a practical post-processing tool "V-SEM" has been developed.

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In order to understand the compressive behaviors of particle-reinforced metal-matrix composite (MMCs) material for its potential usage on light armor, large compressive plastic deformation of MMC composite is investigated through numerical modeling at high strain rates. Based on the work of Li and Remash, the numerical modeling is performed using axisymmetric unit cell model, with the particles treated as elastic ellipsoids or cylinders embedded within a visco-plastic matrix. Five particle volume fractions from 10% to 50% and three aluminum matrix materials LY12CZ, LC4 and 7075 are analyzed. The contribution of this work is to add a term to the original analytical model. Thus it can take account the effect of strain hardening of the matrix material. The modified analytical model introduced here is able to better describe the features of the computational predictions at certain extent.

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Strain-induced anisotropy is one of the critical issues in sheet metal forming which includes strain path change. In this study anisotropic hardening behavior in multiple-step tensile test, which has been investigated by several researchers recently, was reproduced by using micro-structural based hardening model which can take the evolution of intragranular dislocation structure into account.

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The paper presents an application of Boundary Element Method (BEM)-based technique to the estimation of multidimensional, spatially and temporarily highly-varied, boundary conditions in thermoelasticity problems. The BEM is employed for numerically effective and accurate calculation of sensitivity coefficients. The set of sensitivity/constraints equations is solved employing the derived algorithm with regularization inherent via covariance matrices a priori, and combined with function specification approach (piece-wise linear approximation of time variation).

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The variable matrices method, that was based on the properties that adaptive structures could identify their own unknown structural characteristics by their variable and controllable structural parameters, was proposed to identify structural matrices. Also, the effect of the number of variable structural parameters and identifiable degress of freedom of the structural matrix on the accuracy of identification was shown. A simple spring-mass system attached with variable stiffness spring was demonstrated to investigate the limits and possibilities of the proposed methods. Numerical examples showed that some combinations of measured mode, location of variable parameters and their changing range had difficulties to identify the exact stiffness matrix, while the other combinations identified exact one.

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This paper presents the development of 3-D moisture absorption analysis method of Flip-chip BGA (Ball Grid Array) package. To realize the discontinuity of moisture content at the material interface, an efficient finite element model was proposed which is derived from the extended thermal-moisture analogy. The simulation result of package moisture content under conditions of 30℃/70%RH and 85℃/65%RH was in good agreement with the experimental result. This method can be used by any moisture absorption analysis of multi-material package.

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