H. T. Xiao^1,2,3, Y. Y. Xie^1,2, Z. Q. Yue⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.1, pp. 55-80, 2015, DOI:10.3970/cmes.2015.109.055

Abstract This paper examines the problem of a square-shaped crack embedded in a layered half-space whose external surface is subject to a uniform loading over a rectangular area. Two novel numerical methods and the superposition principle in fracture mechanics are employed for the analysis of the crack problem. The numerical methods are based on the fundamental solution of a multilayered elastic medium and are, respectively, applied to calculate the stress fields of layered halfspace without cracks and the discontinuous displacements of crack surfaces in layered halfspace. The stress intensity factor (SIF) values are calculated using discontinuous displacements and the influence of… More >

Y. Wang¹, E. Lü^1,2, J. Zhao¹, J. Guo¹

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.1, pp. 35-53, 2015, DOI:10.3970/cmes.2015.109.035

Abstract Meshfree methods have found good applications in many new researches, which show very good potential to be powerful numerical tools. As an alternative to the mesh based methods, meshfree methods have the advantage of not using a predefined mesh for the domain discretization. In this study, a mesh free scheme based on the radial point interpolation method was used to solve the topological design of microstructures for composite materials. The explicit form of the radial point interpolation method (RPIM) interpolation augmented with polynomials is presented, which satisfies range-restricted properties and is applicable to integrate a physically meaningful density interpolation. Meanwhile… More >

Y.C. Shiah¹, C.L. Tan^2,3, Li-Ding Chan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.1, pp. 15-33, 2015, DOI:10.3970/cmes.2015.109.015

Abstract In the conventional boundary element method (BEM), the presence of singular kernels in the boundary integral equation or integral identities causes serious inaccuracy of the numerical solutions when the source and field points are very close to each other. This situation occurs commonly in elastostatic analysis of thin structures. The numerical inaccuracy issue can be resolved by some regularization process. Very recently, the self-regularization scheme originally proposed by Cruse and Richardson (1996) for 2D stress analysis has been extended and modified by He and Tan (2013) to 3D elastostatics analysis of isotropic bodies. This paper deals with the extension of… More >

W.H. Chen¹, H.C. Cheng^2,3, C.F. Yu^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.1, pp. 1-13, 2015, DOI:10.3970/cmes.2015.109.001

Abstract This study aims at exploring the interfacial adhesion strength between solder bump and four typical under bump metallurgies (UBMs), i.e., Cu/Ni, Cu/TiW, Cu/Ni/Cr and /Cu/V/Cr, at atomistic scale. The average bond length and interfacial adhesion stress of the Sn-3.5Ag/Cu/Ni, Sn-3.5Ag/Cu/TiW, Sn-3.5Ag/Cu/Ni/Cr and Sn-3.5Ag/Cu/V/Cr micro-bump interconnects are calculated through the firstprinciples density functional theory (DFT) calculation to estimate the interfacial adhesion strength between the solder bump and UBMs. In addition, by investigating the electric field effect on the average bond length and adhesive stress, the combination of solder bump and UBM with better interfacial adhesion strength and electromigration resistance ability can… More >

Daisuke Ishihara^1,2, Tomoyoshi Horie¹, Tomoya Niho¹, Akiyoshi Baba³

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.6, pp. 429-452, 2015, DOI:10.3970/cmes.2015.108.429

Abstract In this study, a hierarchal decomposition is proposed to solve the structure- fluid-electrostatic interaction in a microelectromechanical system (MEMS). In the proposed decomposition, the structure-fluid-electrostatic interaction is partitioned into the structure-fluid interaction and the electrostatic field using the iteratively staggered method, and the structure-fluid interaction is split into the structurefluid velocity field and the fluid pressure field using the projection method. The proposed decomposition is applied to a micro cantilever beam actuated by the electrostatic force in air. It follows from the comparisons among the numerical and experimental results that the proposed method can predict the MEMS vibration characteristics accurately. More >

Cong Xie¹, Guangyu Shi^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.6, pp. 397-427, 2015, DOI:10.3970/cmes.2015.108.397

Abstract The static and dynamic thermoelastic analyses of the beams made of functionally graded materials (FGMs) are presented in this paper. Based on the refined third-order shear deformation beam theory proposed by the senior author and the variational principle, the governing equations of FG beams are deduced. The influence of temperature on Young’s modulus and coefficients of thermal expansion is taken into account when FG beams are subjected to thermal loading. The resulting governing equations are a system of the eighth-order differential equations in terms of displacement variables, and the thermoelastic coupling is included in the equations. An accurate and reliable… More >

H. Rafieayan Zadeh¹, M. Mohammadi^1,2, E. Babolian¹

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.6, pp. 375-396, 2015, DOI:10.3970/cmes.2015.108.375

Abstract A local reproducing kernel method based on spatial trial space spanned by the Newton basis functions in the native Hilbert space of the reproducing kernel is proposed. It is a truly meshless approach which uses the local sub clusters of domain nodes for approximation of the arbitrary field. It leads to a system of ordinary differential equations (ODEs) for the time-dependent partial differential equations (PDEs). An adaptive algorithm, so-called adaptive residual subsampling, is used to adjust nodes in order to remove oscillations which are caused by a sharp gradient. The method is applied for solving the Allen-Cahn and Burgers’ equations.… More >

Di Wu¹, Wei Gao^1,2, Chongmin Song¹, Zhen Luo³

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.5, pp. 331-373, 2015, DOI:10.3970/cmes.2015.108.331

Abstract Two novel mathematical programming approaches are proposed to separately assess non-deterministic behaviour and stability of engineering structures against disparate uncertainties. Within the proposed computational schemes, uncertainties attributed by the material properties, loading regimes, as well as environmental influences are simultaneously incorporated and modelled by the interval approach. The proposed mathematical programming approaches proficiently transform the uncertain structural analyses into deterministic mathematical programs. Two essential aspects of structural analysis, namely linear structural behaviour and bifurcation buckling, have been explicitly investigated. Diverse verifications have been implemented to justify the accuracy and computational efficiency of the proposed approaches through practically motivated numerical examples. More >

Jun Huang^1,2, Chaopu Zhang¹, Song Xiang², Liu Yang¹, Mingxu Yi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.5, pp. 315-330, 2015, DOI:10.3970/cmes.2015.108.315

Abstract In order to accurately predict the aerodynamic noise of the propeller, a hybrid method combining Computational Fluid Dynamics (CFD) method with Boundary Element Method (BEM) is developed in this paper. The calculation includes two steps: firstly, the unsteady viscous flow around the propeller is calculated using the CFD method to acquire the noise source information; secondly, the radiated sound pressure is calculated using BEM method in the frequency domain. In comparison with the experimental results from wind tunnel, the calculated results of aerodynamic performance are rather desirable. The simulation and experimental results of aerodynamic noise are well fitted. The directivity… More >

Zhimin Chen^1,2, Yuanxin Qu¹, Yuming Bo¹, Yongliang Zhang¹, Bo Cong¹, Xinfeng Yu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.5, pp. 303-313, 2015, DOI:10.3970/cmes.2015.108.303

Abstract For the sake of a higher accuracy of active aircraft GPS tracking, the tracking algorithm based on pseudo-linear Kalman filter is hereby proposed. This algorithm simplifies geometrical and algebraic relations to obtain a pseudo-linear model, then tracking the target by means of Kalman filter algorithm. Meanwhile, the tracking algorithm is studied to build a velocity & position tracking model and a velocity & acceleration tracking model. As shown by the experimental result, the tracking algorithm based on pseudo-linear Kalman filter can meet the requirement of active aircraft GPS tracking, but also attain a higher tracking accuracy in velocity & acceleration… More >