Christopher A. Lemmon^1,2, Nathan J. Sniadecki³, Sami Alom Ruiz^1,3, John L. Tan, Lewis H. Romer^2,4,5, Christopher S. Chen^3,4

Molecular & Cellular Biomechanics, Vol.2, No.1, pp. 1-16, 2005, DOI:10.3970/mcb.2005.002.001

Abstract The interplay of mechanical forces between the extracellular environment and the cytoskeleton drives development, repair, and senescence in many tissues. Quantitative definition of these forces is a vital step in understanding cellular mechanosensing. Microfabricated post array detectors (mPADs) provide direct measurements of cell-generated forces during cell adhesion to extracellular matrix. A new approach to mPAD post labeling, volumetric imaging, and an analysis of post bending mechanics determined that cells apply shear forces and not point moments at the matrix interface. In addition, these forces could be accurately resolved from post deflections by using images of More >

Haitao Wang¹, Zhenhan Yao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.7, No.1, pp. 85-96, 2005, DOI:10.3970/cmes.2005.007.085

Abstract This paper addresses a new boundary element method (BEM) for the numerical analysis of mechanical properties in 3D particle-reinforced composites. The BEM is accelerated by a new version fast multipole method (FMM) in order to perform large scale simulation of a representative volume element (RVE) containing up to several hundred randomly distributed elastic spherical particles on only one personal computer. The maximum number of degrees of freedom (DOF) reaches more than 300,000. Efficiency of the developed new version fast multipole BEM code is evaluated compared with other conventional solutions for BEM. The effects of micro-structural More >

H. C. Cheng¹, C. Y. Yu², W. H. Chen³

CMES-Computer Modeling in Engineering & Sciences, Vol.7, No.1, pp. 1-18, 2005, DOI:10.3970/cmes.2005.007.001

Abstract In this study, a simple but effective solution methodology that integrates a modified global/local finite element (GLFE) modeling technique and a two-staged constitutive modeling strategy is presented for the thermal-mechanical modeling of solder joints in an area array typed electronic package for characterizing the associated solder joint fatigue life under the JEDEC temperature cycling specification. The effectiveness and applicability of the proposed technique are demonstrated through two case studies, each of which is associated with an area array typed test vehicle. The geometry profile of solder joints in the test vehicle is determined by the… More >

Yunfa Zhang¹, Zihui Xia^1,2

CMC-Computers, Materials & Continua, Vol.2, No.3, pp. 213-226, 2005, DOI:10.3970/cmc.2005.002.213

Abstract In the present study, the initiation and evolution of the interphase damage and their influences on the global stress-strain relation of composite laminates are predicted by finite element analysis on a micromechanical unit cell model. A thin layer of interphase elements is introduced and its stress-strain relation is derived based on a cohesive law which describes both normal and tangential separations at the interface between the fiber and matrix. In addition, a viscous term is added to the cohesive law to overcome the convergence difficulty induced by the so-called snap-back instability in the numerical analysis. More >

R. Matsumoto, M. Nakagaki

CMES-Computer Modeling in Engineering & Sciences, Vol.10, No.3, pp. 187-198, 2005, DOI:10.3970/cmes.2005.010.187

Abstract Large-scale molecular dynamics simulations of tensile deformation of amorphous metals containing a nano-crystalline particle were performed in order to clarify the effects of particle size and crystal volume fraction on the deformation mechanism and strength. It became clear that particle size has very little effect, while crystal volume fraction has a substantial influence. Elastic modulus and flow stress intensify as crystal volume fraction increases. Furthermore, the stress in the crystal phase continues to increase, even after yielding in the amorphous phase. Consequently, work-hardening effects appear, preventing localization of plastic deformation. Thus, the dispersed nano-crystalline particles… More >

Y. C. Hon¹, L. Ling², K. M. Liew³

CMC-Computers, Materials & Continua, Vol.2, No.1, pp. 39-50, 2005, DOI:10.3970/cmc.2005.002.039

Abstract In this paper we investigate a thermal driven Micro-Electrical-Mechanical system which was originally designed for inkjet printer to precisely deliver small ink droplets onto paper. In the model, a tiny free-ended beam of metal bends and projects ink onto paper. The model is solved by using the recently developed radial basis functions method. We establish the accuracy of the proposed approach by comparing the numerical results with reported experimental data. Numerical simulations indicate that a light (low composite mass) beam is more stable as it does not oscillate much. A soft (low rigidity) beam results More >

A. Shukla^1,1, A.R. Dunn^2,2, M.A. Moses^3,3, K.J. Van Vliet^4,4

Molecular & Cellular Biomechanics, Vol.1, No.4, pp. 279-290, 2004, DOI:10.3970/mcb.2004.001.279

Abstract Although it is established that endothelial cells can respond to external mechanical cues (e.g., alignment in the direction of fluid shear stress), the extent to which mechanical stress and strain applied via the endothelial cell substrate impact biomolecular and cellular processes is not well-understood. This issue is particularly important in the context of inflammation, vascular remodeling, and cancer progression, as each of these processes occurs concurrently with localized increases in strain and marked changes in molecules secreted by adjacent cells. Here, we systematically vary the level and duration of cyclic tensile strain applied to human… More >

Min Yue^1,1, Jeanne C. Stachowiak^1,1,2,2, Arunava Majumdar^1,1,3,3

Molecular & Cellular Biomechanics, Vol.1, No.3, pp. 211-220, 2004, DOI:10.3970/mcb.2004.001.211

Abstract Microchips;ontaining arrays of cantilever beams have been used to mechanically detect and quantitatively analyze multiple reactions of DNA hybridization and antigen-antibody binding simultaneously. The reaction-induced deflection of a cantilever beam reflects the interplay between strain energy increase of the beam and the free energy reduction of a reaction, providing an ideal tool for investigating the connection between mechanics and chemistry of biomolecular reactions. Since free energy reduction is common for all reactions, the cantilever array forms a universal platform for label-free detection of various specific biomolecular reactions. A few such reactions and their implications in More >

Wan-Sul Lee, Kie-Chan Kwon, Bong-Kyu Kim, Ji-Hyon Cho, Sung-Kie Youn¹

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.3, pp. 279-286, 2004, DOI:10.3970/cmes.2004.005.279

Abstract A numerical approach for eigenvalue analysis of the electrostatically tunable micro-mechanical actuators is presented. An efficient algorithm for calculating the natural frequency shifting in the micro-mechanical actuators due to applied DC turning voltage is proposed. In the calculations of the coupled field problem, the three-dimensional FEM/BEM approaches and iterative staggered algorithm are employed. The numerical examples for actually fabricated actuators are presented and the numerical analysis results are compared with experimental data. More >

D. P. Ghosh¹, S. Gopalakrishnan²

CMC-Computers, Materials & Continua, Vol.1, No.3, pp. 213-228, 2004, DOI:10.3970/cmc.2004.001.213

Abstract Anhysteretic, coupled, linear and nonlinear constitutive relationship for magnetostrictive material is studied in this paper. Constitutive relationships of magnetostrictive material are represented through two equations, one for actuation and other for sensing, both of which are coupled through magneto-mechanical coefficient. Coupled model is studied without assuming any explicit direct relationship with magnetic field. In linear-coupled model, which is assumed to preserve the magnetic flux line continuity, the elastic modulus, the permeability and magneto-elastic constant are assumed as constant. In nonlinear-coupled model, the nonlinearity is decoupled and solved separately for the magnetic domain and mechanical domain More >