Nadipuram R. Prasad¹, Salvador Almanza-Garcia¹, Thomas T. Lu²

CMC-Computers, Materials & Continua, Vol.14, No.1, pp. 1-22, 2009, DOI:10.3970/cmc.2009.014.001

Abstract The paper presents a revolutionary framework for the modeling, detection, characterization, identification, and machine-learning of anomalous behavior in observed phenomena arising from a large class of unknown and uncertain dynamical systems. An evolved behavior would in general be very difficult to correct unless the specific anomalous event that caused such behavior can be detected early, and any consequence attributed to the specific anomaly following its detection. Substantial investigative time and effort is required to back-track the cause for abnormal behavior and to recreate the event sequence leading to such abnormal behavior. The need to automatically detect anomalous behavior is therefore… More >

Hao-Miao Zhou¹, Fang Li¹, Qiang Ye¹, Ji-Xiang Zhao¹, Zhe-Lei Xia¹, YingTang², Jing Wei³

CMC-Computers, Materials & Continua, Vol.13, No.3, pp. 235-248, 2009, DOI:10.3970/cmc.2009.013.235

Abstract At present, there are many methods about Young's modulus measurement of thin films, but so far there is no recognized simple, non-destructive and cheaper standard measurement method. Considering thin films with various thicknesses were sputter deposited on the magnetostrictive resonator and monitoring the resonator's first-order longitudinal resonant frequency shift both before and after deposition induced by external magnetic field, an Young's modulus assessing method based on classical laminated plate theory is presented in this paper. Using the measured natural frequencies of Au, Cu, Cr, Al and SiC materials with various thicknesses in the literature, the Young's modulus of the five… More >

Wen Chen^1,2, Zhuo-Jia Fu^1,3, Qing-Hua Qin³

CMC-Computers, Materials & Continua, Vol.13, No.3, pp. 201-218, 2009, DOI:10.3970/cmc.2009.013.201

Abstract This paper presents high-order Trefftz functions for some commonly used differential operators. These Trefftz functions are then used to construct boundary particle method for solving inhomogeneous problems with the boundary discretization only, i.e., no inner nodes and mesh are required in forming the final linear equation system. It should be mentioned that the presented Trefftz functions are nonsingular and avoids the singularity occurred in the fundamental solution and, in particular, have no problem-dependent parameter. Numerical experiments demonstrate the efficiency and accuracy of the present scheme in the solution of inhomogeneous problems. More >

Dyi-Cheng¹, Syuan-Yi Syong¹

CMC-Computers, Materials & Continua, Vol.13, No.3, pp. 191-200, 2009, DOI:10.3970/cmc.2009.013.191

Abstract Finite element simulations are performed to investigate the plastic deformation behavior of Ti-6Al-4V titanium alloy during its indirect extrusion through a four-hole die. The simulations assume the die, mandrel and container to be rigid bodies and ignore the temperature change induced during the extrusion process. Under various extrusion conditions, the present numerical analysis investigates the effective stress and profile of product at the exit. The relative influences of the friction factors, the temperature of billet and the eccentricity of four-hole displacement are systematically examined. The simulations focus specifically on the effects of the friction factor, billet temperature and eccentricity ratio… More >

B. Tomas Johansson¹, Liviu Marin²

CMC-Computers, Materials & Continua, Vol.13, No.2, pp. 153-190, 2009, DOI:10.3970/cmc.2009.013.153

Abstract We propose two algorithms involving the relaxation of either the given Dirichlet data or the prescribed Neumann data on the over-specified boundary, in the case of the alternating iterative algorithm of Kozlov, Maz'ya and Fomin(1991) applied to Cauchy problems for the modified Helmholtz equation. A convergence proof of these relaxation methods is given, along with a stopping criterion. The numerical results obtained using these procedures, in conjunction with the boundary element method (BEM), show the numerical stability, convergence, consistency and computational efficiency of the proposed methods. More >

Xiaoyi Liang¹, Zhen Yang^1,2, Xingsheng Gu³, Licheng Ling¹

CMC-Computers, Materials & Continua, Vol.13, No.2, pp. 135-152, 2009, DOI:10.3970/cmc.2009.013.135

Abstract Supercapacitors, also called electrical double-layer capacitors (EDLCs), occupy a region between batteries and dielectric capacitors on the Ragone plot describing the relation between energy and power. BET specific surface area and specific capacitance are two important electrochemical property parameters for activated carbon EDLCs, which are usually tested by experimental method. However, it is misspent time to repeat lots of experiments for EDLCs' studies. In this investigation, we developed one theoretical model based on improved particle swarm optimization algorithm back propagation (PSO-BP) neural network (NN) to simulate and optimize BET specific surface area and specific capacitance. Comparative studies between the predicted… More >

D.P.Mondal¹, S.Das¹, Anshul Badkul¹, Nidhi Jha¹

CMC-Computers, Materials & Continua, Vol.13, No.2, pp. 115-134, 2009, DOI:10.3970/cmc.2009.013.115

Abstract The cooling effect by evaporative liquid is modeled by considering that heat is transferred from the system to the surrounding due to evaporation of liquid through the pores present in the medium. The variation of cooling rate with cell size, volume fraction of pores and physical conditions has been analyzed. The model demonstrates that it increases with increase in thickness of the foam slab and with increase in velocity of air. It is also observed that cooling effect decreases with decrease in volume fraction of porosity and with increase in relative density, cell size, thermal conductivity and relative humidity. More >

De-Shin Liu¹, Zhen-Wei Zhuang^1,2, Cho-LiangChung³, Ching-Yang Chen⁴

CMC-Computers, Materials & Continua, Vol.13, No.2, pp. 89-114, 2009, DOI:10.3970/cmc.2009.013.089

Abstract This paper employs a novel numerical technique, designated as the hybrid moisture element method (HMEM), to model and analyze moisture diffusion in a heterogeneous epoxy resin containing multiple randomly distributed particles. The HMEM scheme is based on a hybrid moisture element (HME), whose properties are determined by equivalent moisture capacitance and conductance matrixes calculated using the conventional finite element formulation. A coupled HME-FE scheme is developed and implemented using the commercial FEM software ABAQUS. The HME-FE scheme is then employed to analyze the moisture diffusion characteristics of a heterogeneous epoxy resin layer containing particle inclusions. The analysis commences by comparing… More >

W.F.Yuan¹, K.H.Tan ¹

CMC-Computers, Materials & Continua, Vol.13, No.1, pp. 49-62, 2009, DOI:10.3970/cmc.2009.013.049

Abstract A simple cellular automaton (CA) scheme is proposed to simulate heat conduction in anisotropic domains. The CA is built on random nodes rather than an irregular grid. The local rule used in the CA is defined by physical concepts instead of differential equations. The accuracy of the proposed approach is verified by classical examples. As an application of the proposed method, the CA approach is incorporated into fibre model which is widely used in finite element analysis to calculate the temperature distribution on the cross-section of composite beams. Numerical examples demonstrate that the proposed scheme can be conveniently applied to… More >

J.A.Ferreira^1,2, P. de Oliveira², P. da Silva³, D. M. G. Comissiong⁴

CMC-Computers, Materials & Continua, Vol.13, No.1, pp. 17-48, 2009, DOI:10.3970/cmc.2009.013.017

Abstract A phenomenological formulation is adopted to investigate desorption in polymers. The speed of the front is studied and the well-posedness of the general model is analyzed. Numerical simulations illustrating the dynamics of the desorption process described by the proposed model are included. More >