TakehikoNakama¹

CMC-Computers, Materials & Continua, Vol.14, No.1, pp. 35-60, 2009, DOI:10.3970/cmc.2009.014.035

Abstract Random noise perturbs objective functions in practical optimization problems, and genetic algorithms (GAs) have been proposed as an effective optimization tool for dealing with noisy objective functions. In this paper, we investigate GAs in a variety of noisy environments where fitness perturbation can occur in any form-for example, fitness evaluations can be concurrently disturbed by additive and multiplicative noise. We reveal the convergence properties of GAs by constructing and analyzing a Markov chain that explicitly models the evolution of the algorithms in noisy environments. We compute the one-step transition probabilities of the Markov chain and show that the chain has… More >

S.H. Kwon¹, H.K. Lee²

CMC-Computers, Materials & Continua, Vol.12, No.3, pp. 197-222, 2009, DOI:10.3970/cmc.2009.012.197

Abstract The electromagnetic shielding effectiveness of steel fiber-reinforced mortar was numerically examined in this study. A series of numerical analysis on twenty-seven types of specimens of different diameters, lengths, and volume fractions of fibers were conducted using the FE program HFSS to investigate the effect of the dimensions of steel fibers and the amount of fibers added to the mortar on the shielding effectiveness. S-parameters of some specimens were experimentally measured by the free space method and the experimentally measured S-parameters were compared with those computed in order to verify the present numerical analysis method. It was found that smaller diameters… More >

E.J. Sapountzakis¹, V.G. Mokos¹

CMC-Computers, Materials & Continua, Vol.12, No.2, pp. 157-196, 2009, DOI:10.3970/cmc.2009.012.157

Abstract In this paper a general solution for the elastic buckling analysis of plates stiffened by arbitrarily placed parallel beams of arbitrary doubly symmetric cross section subjected to an arbitrary inplane loading is presented. According to the proposed model, the stiffening beams are isolated from the plate by sections in the lower outer surface of the plate, taking into account the arising tractions in all directions at the fictitious interfaces. These tractions are integrated with respect to each half of the interface width resulting two interface lines, along which the loading of the beams as well as the additional loading of… More >

Ming-Hsiao Lee, Wen-Hwa Chen

CMC-Computers, Materials & Continua, Vol.11, No.1, pp. 59-78, 2009, DOI:10.3970/cmc.2009.011.059

Abstract On the analysis of electrostatic-structural coupled problems as encountered in many electrostatic driven MEMS devices, the electrostatic analysis domain is often extremely distorted due to the deflection of the structure. This kind of problem is difficult to be dealt with by almost all kinds of available numerical methods. A new three-dimensional meshless scheme with background grid is thus proposed herein. By this scheme, a three-dimensional fixed background grid with regularly-distributed nodes is utilized. Another set of discretized boundary grid is employed to describe the boundary surfaces of both the structure and the electrostatic field. The analysis electrostatic/structural domains are modeled… More >

Syh-Tsang Jenq^1,2, Yuen-Sheng Chiu²

CMC-Computers, Materials & Continua, Vol.11, No.1, pp. 33-58, 2009, DOI:10.3970/cmc.2009.011.033

Abstract Current work studies the transient hydroplaning behavior of 200 kPa inflated pneumatic radial tires with various types of tread patterns. Tires were numerically loaded with a quarter car weight of 4 kN, and then accelerated from rest rolling over a water film with a thickness of 5, 10 and 15 mm on top of a flat pavement. Tire structure is composed of outer rubber tread and inner fiber reinforcing composite layers. The Mooney-Rivlin constitutive law and the classical laminated theory (CLT) were, respectively, used to describe the mechanical behavior of rubber material and composite reinforcing layers. The tire hydroplaning phenomenon… More >

Ching-Chi Hsu¹, Jinn Lin², Yongyut Amaritsakul³, Takalamesar Antonius³, Ching-Kong Chao^3,4

CMC-Computers, Materials & Continua, Vol.11, No.1, pp. 1-14, 2009, DOI:10.3970/cmc.2009.011.001

Abstract Dynamic hip screw and gamma nail have been widely used to treat the patients with proximal femoral fractures, but clinical failures of those implants are still to be found. This study developed three-dimensional finite element models to investigate the biomechanical performances of the implants. Two kinds of commercially available implants (dynamic hip screw and gamma nail) and one newly designed implant (double screw nail) under three kinds of the proximal femoral fractures (neck fracture, subtrochanteric fracture, and subtrochanteric fracture with gap) were evaluated. Double screw nail showed better biomechanical performances than dynamic hip screw and gamma nail. Two commercially available… More >

J.H. Tian^1,2, X. Han², S.Y. Long³, G.Q. Xie⁴

CMC-Computers, Materials & Continua, Vol.10, No.3, pp. 229-242, 2009, DOI:10.3970/cmc.2009.010.229

Abstract A heat conduction analysis of the functionally graded material (FGM) plates has been investigated based on the hybrid numerical method (HNM). HNM combines the layer element method with the method of Fourier transforms and proves to be efficient and reliable. The FGM plates are infinite large and the material properties vary continuously through thickness. The heat source continually acted one the FGM plates. The temperature distribution of the FGM plates is obtained in different time and different position. Some useful results for heat conduction problems are shown in figures. This article applies HNM to heat conduction firstly and provides us… More >

D.W. Kelly¹, M.C.W. Lee¹, A.C. Orifici^2,3, R.S.Thomson³, R. Degenhardt^4,5

CMC-Computers, Materials & Continua, Vol.10, No.2, pp. 163-194, 2009, DOI:10.3970/cmc.2009.010.163

Abstract An experimental program for collapse of curved stiffened composite shell structures encountered a wide range of initial and deep buckling mode shapes. This paper presents work to determine the significance of the buckling deformations for determining the final collapse loads and to understand the source of the variation. A finite element analysis is applied to predict growth of damage that causes the disbonding of stiffeners and defines a load displacement curve to final collapse. The variability in material properties and geometry is then investigated to identify a range of buckling modes and development of deep postbuckling deformation encountered in the… More >

X.G. Yuan¹, R.J. Zhang²

CMC-Computers, Materials & Continua, Vol.3, No.3, pp. 119-130, 2006, DOI:10.3970/cmc.2006.003.119

Abstract In this paper, the problem of cavity formation and motion in an incompressible transversely isotropic nonlinearly elastic solid sphere, which is subjected to a uniform radial tensile dead load on its surface, is examined in the context of nonlinear elastodynamics. The strain energy density associated with the nonlinearly elastic material may be viewed as the generalized forms of some known material models. It is proved that some determinate conditions must be imposed on the form of the strain energy density such that the surface tensile dead load has a finite critical value. Correspondingly, as the surface tensile dead load exceeds… More >

P. B. Wang¹, Z. H. Yao^1,2, T. Lei¹

CMC-Computers, Materials & Continua, Vol.3, No.2, pp. 65-76, 2006, DOI:10.3970/cmc.2006.003.065

Abstract The fast multipole method (FMM) is applied to the dual boundary element method (DBEM) for the analysis of finite solids with large numbers of microcracks. The application of FMM significantly enhances the run-time and memory storage efficiency. Combining multipole expansions with local expansions, computational complexity and memory requirement are both reduced to O(N), where N is the number of DOFs (degrees of freedom). This numerical scheme is used to compute the effective in-plane bulk modulus of 2D solids with thousands of randomly distributed microcracks. The results prove that the IDD method, the differential method, and the method proposed by Feng… More >