D. S. Liu¹, C. Y. Tsai¹, S. R. Lyu²

CMC-Computers, Materials & Continua, Vol.11, No.2, pp. 147-164, 2009, DOI:10.3970/cmc.2009.011.147

Abstract This study presents a novel numerical method for extracting the tempe -rature-dependent mechanical properties of the gold and aluminum thin-films. In the proposed approach, molecular dynamics (MD) simulations are performed to establish the load-displacement response of the thin substrate nanoindented at temperatures ranging from 300-900 K. A simple but effective procedure involving genetic algorithm (GA) and finite element method (FEM) is implemented to extract the material constants of the gold and aluminum substrates. The material constants are then used to construct the corresponding stress-strain curve, from which the elastic modulus, yield stress and the tangent More >

Hsien-Chie Cheng¹, Yu-Chen Hsu², Wen-Hwa Chen²

CMC-Computers, Materials & Continua, Vol.11, No.2, pp. 127-146, 2009, DOI:10.3970/cmc.2009.011.127

Abstract Due to the limitation of fabrication technologies nowadays, structural or atomistic defects are often perceived in carbon nanotubes (CNTs) during the manufacturing process. The main goal of the study aims at providing a systematic investigation of the effects of atomistic defects on the nanomechanical properties and fracture behaviors of single-walled CNTs (SWCNTs) using molecular dynamics (MD) simulation. Furthermore, the correlation between local stress distribution and fracture evolution is studied. Key parameters and factors under investigation include the number, type (namely the vacancy and Stone-Wales defects), location and distribution of defects. Results show that the nanomechanical More >

Yeau-Ren Jeng¹,Ping-Chi Tsai¹,Guo-Zhe Huang¹, I-Ling Chang¹

CMC-Computers, Materials & Continua, Vol.11, No.2, pp. 109-126, 2009, DOI:10.3970/cmc.2009.011.109

Abstract This study performs a series of Molecular Dynamics (MD) and Molecular Statics (MS) simulations to investigate the mechanical properties of single-walled carbon nanotubes (SWCNTs) under a uniaxial tensile strain. The simulations focus specifically on the effects of the nanotube helicity, the nanotube diameter and the percentage of vacancy defects on the bond length, bond angle and tensile strength of zigzag and armchair SWCNTs. In this study, a good agreement is observed between the MD and MS simulation results for the stress-strain response of the SWCNTs in both the elastic and the plastic deformation regimes. The… More >

B Keerthika¹, Y P Cao², D Raabe¹

CMC-Computers, Materials & Continua, Vol.10, No.3, pp. 243-258, 2009, DOI:10.3970/cmc.2009.010.243

Abstract In this study, effects of the plastic deformation and the time-dependent deformation behavior on the fundamental relations in the Oliver & Pharr method are studied by using finite element analysis based on a viscoelastic-plastic model developed for polymers. The study eventually yields an experimental protocol and using which, the instantaneous modulus of the viscoelastic-plastic materials may be reliably determined. Experiments have been performed on four polymers to verify the conclusions from the numerical analysis. More >

F Gentil¹, RM Natal Jorge^2,3, AJM Ferreira⁴, MPL Parente^2,5, PALS Martins^2,6, E Almeida⁷

The International Conference on Computational & Experimental Engineering and Sciences, Vol.8, No.4, pp. 145-150, 2008, DOI:10.3970/icces.2008.008.145

Abstract The ear can be divided anatomically, into three parts: external, middle, and inner ear. The eardrum separates the external from the middle ear. The perforation of the eardrum can result in conductive moderate hearing loss. More >

SAKO Fumiko¹, ADACHI Yukihiro¹, SHI Qinzhong², ANDO Shigemasa², TSUCHIHASHI Masahiro², HAGIWARA Ichiro³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.4, pp. 229-232, 2008, DOI:10.3970/icces.2008.006.229

Abstract Satellite equipment experience severe high random acoustic loads during launch phase. [1\hbox {}] Accurate prediction of this random vibration is demanded to prevent equipmtnt from trouble. In this paper, a new approach for vibro-acoustic coupling analysis is proposed to obtain more accurate prediction. The proposed method applies Mechanical Impedance Method to vibro-acoustic coupling analysis with FEM model of structure and SEA model of sound system. \newline The analysis of simple model is conducted to study the proposed method. The result from the comparison shows this method provides more accurate prediction with structure impedance calculated from More >

N.Ishizuka¹, T.Okada², T.Ikeno², K.Shiomi², M.Okuma³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.2, pp. 145-150, 2008, DOI:10.3970/icces.2008.006.145

Abstract The accurate modeling of structures is very important for any engineering analysis such as simulation and design optimization of mechanical systems for noise and vibration. It is desired that such a modeling process should not be time-consuming and that the created model must have structural dynamic properties corresponding with the actual ones. But in practice, it is often difficult or even impossible to satisfy the desire by using conventional theoretical methods such as the Finite Element Method (FEM) when we consider actual mechanical systems which consist of many substructures. In this paper, under the assumption… More >

M. Uchida¹, N. Tada¹, Y. Tomita²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.2, pp. 91-98, 2008, DOI:10.3970/icces.2008.006.091

Abstract Micro- to mesoscopic deformation behavior of semi-crystalline polymer with randomly distributed rubber particles is evaluated by numerical simulation. In this model, dimension of mesostructure is identified by volume fraction of interface region around the rubber particles. The effects of strain rate and size of mesostructure on macroscopic stress-strain relation and strain distribution in mesoscopic area are discussed. In the earlier stage of deformation, the slope of stress-strain relation changes by rubber particle size while stress in the following deformation is mainly affected by the tensile strain rate. The anisotropic deformation in lamellar oriented interface region More >

Z.D. Wang¹, D.F Li¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.5, No.4, pp. 245-254, 2008, DOI:10.3970/icces.2008.005.245

Abstract The thermo-mechanical constitution of shape memory polymers (SMPs) is critical for predicting their deformation and recovery characteristics under different constraints. In this study, a new, physical-based, temperature and time-dependent constitutive model is proposed for simulating the thermomechanical response of SMPs. The deformation mechanisms of shape fix and shape recovery are analyzed. Different models are compared to compare strain and stress recovery responses with the experimental results. More >

Lihai Zhang^*, Bruce S. Gardiner^*, David W. Smith^*, Peter Pivonka^*, Alan Grodzinsky^†

Molecular & Cellular Biomechanics, Vol.5, No.2, pp. 133-154, 2008, DOI:10.3970/mcb.2008.005.133

Abstract Cartilage maintains its integrity in a hostile mechanical environment. This task is made more difficult because cartilage has no blood supply, and so nutrients and growth factors need to be transported greater distances than normal to reach cells several millimetres from the cartilage surface. The chondrocytes embedded within the extracellular matrix (ECM) are essential for maintaining the mechanical integrity of the ECM, through a balance of degradation and synthesis of collagen and proteoglycans. A chondrocyte senses various chemical and mechanical signals in its local microenvironment, responding by appropriate adaption of the local ECM. Clearly a… More >