Chein-Shan Liu^1,2, Chung-Lun Kuo³, Dongjie Liu⁴

CMC-Computers, Materials & Continua, Vol.24, No.2, pp. 105-124, 2011, DOI:10.3970/cmc.2011.024.105

Abstract The inverse Cauchy problems for elliptic equations, such as the Laplace equation, the Poisson equation, the Helmholtz equation and the modified Helmholtz equation, defined in annular domains are investigated. The outer boundary of the annulus is imposed by overspecified boundary data, and we seek unknown data on the inner boundary through the numerical solution by a spring-damping regularization method and its Lie-group shooting method (LGSM). Several numerical examples are examined to show that the LGSM can overcome the ill-posed behavior of inverse Cauchy problem against the disturbance from random noise, and the computational cost is very cheap. More >

L. Dong¹, S. N. Atluri²

CMC-Computers, Materials & Continua, Vol.24, No.1, pp. 61-104, 2011, DOI:10.3970/cmc.2011.024.061

Abstract A simple procedure to formulate efficient and stable hybrid/mixed finite elements is developed, for applications in macro- as well as micromechanics. In this method, the strain and displacement field are independently assumed. Instead of using two-field variational principles to enforce both equilibrium and compatibility conditions in a variational sense, the independently assumed element strains are related to the strains derived from the independently assumed element displacements, at a finite number of collocation points within the element. The element stiffness matrix is therefore derived, by simply using the principle of minimum potential energy. Taking the four-node plane isoparametric element as an… More >

A. M. Dongare^1,2, A. M. Rajendran³, B. LaMattina⁴, M. A. Zikry¹, D. W. Brenner¹

CMC-Computers, Materials & Continua, Vol.24, No.1, pp. 43-60, 2011, DOI:10.3970/cmc.2011.024.043

Abstract Large-scale molecular dynamics (MD) simulations are used to investigate the effects of microstructure and loading conditions on the dynamic failure behavior of nanocrystalline Cu. The nucleation, growth, and coalescence of voids is investigated for the nanocrystalline metal with average grain sizes ranging from 6 nm to 12 nm (inverse Hall-Petch regime) for conditions of uniaxial expansion at constant strain rates ranging from 4x107 s - 1 to 1010 s - 1. MD simulations suggest that the evolution of voids can be described in two stages: The first stage corresponds to the nucleation of voids and the fast linear initial growth… More >

H. Htike^1,2, W. Chen^1,2,3, Y. Gu^1,2

CMC-Computers, Materials & Continua, Vol.24, No.1, pp. 1-14, 2011, DOI:10.3970/cmc.2011.024.001

Abstract In this paper, we investigate the application of the singular boundary method (SBM) to two-dimensional problems of steady-state heat conduction in isotropic bimaterials. A domain decomposition technique is employed where the bimaterial is decomposed into two subdomains, and in each subdomain, the solution is approximated separately by an SBM-type expansion. The proposed method is tested and compared on several benchmark test problems, and its relative merits over the other boundary discretization methods, such as the method of fundamental solution (MFS) and the boundary element method (BEM), are also discussed. More >

F. Casciati¹, S. Casciati², L. Faravelli¹, A. Marzi¹

CMC-Computers, Materials & Continua, Vol.23, No.3, pp. 287-306, 2011, DOI:10.3970/cmc.2011.023.287

Abstract The potential offered by the main features of shape memory alloys (SMA) in Structural Engineering applications is object of attention since two decades. The main issues concern the predictability of the material behavior and the fatigue lifetime of macro structural elements (as different from wire segments). In this paper, the fatigue characteristics, at given temperatures, of multigrain samples of a specific Cu-based alloy are investigated. The results of laboratory tests on bar specimens are discussed. The target is to model the manner in which the effects of several loading-unloading cycles of different amplitude cumulate. More >

G. M. Kulikov¹, S. V. Plotnikova¹

CMC-Computers, Materials & Continua, Vol.23, No.3, pp. 233-264, 2011, DOI:10.3970/cmc.2011.023.233

Abstract This paper presents a robust non-linear piezoelectric exact geometry (EG) four-node solid-shell element based on the higher-order 9-parameter equivalent single-layer (ESL) theory, which permits one to utilize 3D constitutive equations. The term EG reflects the fact that coefficients of the first and second fundamental forms of the reference surface are taken exactly at each element node. The finite element formulation developed is based on a new concept of interpolation surfaces (I-surfaces) inside the shell body. We introduce three I-surfaces and choose nine displacements of these surfaces as fundamental shell unknowns. Such choice allows us to represent the finite rotation piezoelectric… More >

Kotaro Mori¹, Fumio Narita¹, Yasuhide Shindo¹

CMC-Computers, Materials & Continua, Vol.23, No.3, pp. 187-200, 2011, DOI:10.3970/cmc.2011.023.187

Abstract This work deals with the response of clamped-free magnetostrictive/piezoelectric/magnetostrictive laminates under electric field both numerically and experimentally. The laminate is fabricated using two magnetostrictive Terfenol-D layers and a soft piezoelectric PZT layer. Easy axis of Terfenol-D layers is length direction, while the polarization of PZT layer is the thickness direction. The magnetostriction of the Terfenol-D layers bonded to the upper and lower surfaces of the PZT layer is first measured. Next, a nonlinear finite element analysis is employed to evaluate the second-order magnetoelastic constants in the Terfenol-D layers bonded to the PZT layer using measured data. The induced magnetic field… More >

Hong-Hua Dai^1,2, Jeom Kee Paik³, S. N. Atluri²

CMC-Computers, Materials & Continua, Vol.23, No.2, pp. 155-186, 2011, DOI:10.3970/cmc.2011.023.155

Abstract The application of the Galerkin method, using global trial functions which satisfy the boundary conditions, to nonlinear partial differential equations such as those in the von Karman nonlinear plate theory, is well-known. Such an approach using trial function expansions involving multiple basis functions, leads to a highly coupled system of nonlinear algebraic equations (NAEs). The derivation of such a system of NAEs and their direct solutions have hitherto been considered to be formidable tasks. Thus, research in the last 40 years has been focused mainly on the use of local trial functions and the Galerkin method, applied to the piecewise… More >

C. T. Wu¹, F.-L. Yang², D. L. Young³

CMC-Computers, Materials & Continua, Vol.23, No.2, pp. 135-154, 2011, DOI:10.3970/cmc.2011.023.135

Abstract This paper proposes a method that can calculate the hydrodynamic force of a non-circular object in an inviscid, irrotational, and incompressible flow with the presence of external flow singularities. In order to handle irregular object, the method of fundamental solutions (MFS) is employed to numerically construct the singularity system that describes the body and the flow motion and meets the boundary condition. The obtained singularity system is then integrated into the generalized Lagally theorem to compute the instantaneous hydrodynamic force via algebraic calculations and to describe the unsteady interaction of the object and its ambient flow. The proposed method is… More >

Xiaonan Hou¹, Hong Hu¹, Yanping Liu¹, Vadim Silberschmidt²

CMC-Computers, Materials & Continua, Vol.23, No.2, pp. 119-134, 2011, DOI:10.3970/cmc.2011.023.119

Abstract Compressibility of warp-knitted spacer fabrics is one of their important mechanical properties with regard to many special applications such as body protection, cushion and mattresses. Due to specific structural features of the fabric and a non-linear mechanical behavior of monofilaments, the compression properties of this kind of fabrics are very complicated. Although several studies have been performed to investigate their compression behavior, its mechanism has not well been understood yet. This work is concerned with a study of compression mechanism of a selected warp-knitted spacer fabric with a given sandwich structure. Both experimental and numerical methods are used to study… More >