Cherl-Hee Lee, Jonghun Lee¹

CMC-Computers, Materials & Continua, Vol.39, No.3, pp. 289-299, 2014, DOI:10.3970/cmc.2014.039.289

Abstract The broadband design of a metamaterials-based zeroth-order resonance (ZOR) mushroom antenna with an I-shaped slit is presented and experimentally studied. The presented metamaterials-based antenna uses a unit cell based on a composite right/left handed (CRLH) transmission line and can provide a ZOR frequency. By designing the I-shaped slot resonance frequency adjacently to the ZOR frequency, the presented antenna can achieve a 10-dB bandwidth enhancement of roughly 7 times with respect to a conventional rectangular-shaped mushroom structure. More >

Leiting Dong^1,2, Satya N. Atluri^1,3

CMC-Computers, Materials & Continua, Vol.33, No.2, pp. 111-154, 2013, DOI:10.3970/cmc.2013.033.111

Abstract In this study, SGBEM Voronoi Cells (SVCs), with each cell representing a grain of the material at the micro-level, are developed for direct micromechanical numerical modeling of heterogeneous composites. Each SVC can consist of either a (each with a different) homogenous isotropic matrix, and can include micro-inhomogeneities such as inclusions, voids of a different material, and cracks. These inclusions and voids in each SVC can be arbitrarily-shaped, such as circular, elliptical, polygonal, etc., for 2D problems. Further, the cracks in each SVC can be fully-embedded, edge, branching, or intersecting types, with arbitrary curved shapes. By… More >

Yuping Zhu^1,2, Tao Shi¹, Yuanbing Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.95, No.6, pp. 501-517, 2013, DOI:10.3970/cmes.2013.095.501

Abstract Single crystal ferromagnetic shape memory alloy is a kind of new intelligent materials, it shows obvious anisotropy. Micromechanics theory has been used to analyze the whole mechanical behaviors of this material. However, Eshelby’s tensor of this material which plays an important role has still not solved efficiently. Based on the existing micromechanics constitutive model, this paper analyzes the numerical calculation formula of Eshelby’s tensor of anisotropic ferromagnetic shape memory alloy. Adopting the way of Gauss integral, the optimal Gaussian integral points for different inclusion shapes and the corresponding numerical solution of Eshelby’s tensor are obtained.Furthermore, More >

Bingfei Liu¹, Guansuo Dui^2,3, Lijun Xue², Benming Xie¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.3, pp. 239-260, 2013, DOI:10.32604/cmes.2013.094.239

Abstract Analytical solutions are derived for the macroscopic behaviors of a Shape Memory Alloy (SMA) thick-walled cylinder subjected to internal pressure and radial temperature gradient. The Tresca transformation criterion and linear hardening are used. Equations are given for the radial and circumferential stresses, transformation strains and martensite volume fractions at both the elastic step and the transformation step. Numerical results are presented and in good agreement with the finite element simulations. More >

Lijun Xue¹, Guansuo Dui^1,2, Bingfei Liu³

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.1, pp. 1-16, 2013, DOI:10.3970/cmes.2013.093.001

Abstract The Functionally Graded Shape Memory Alloy (FG-SMA) is a new kind of functional materials which possesses the excellent properties of both Shape Memory Alloy (SMA) and Functionally Graded Material (FGM). A macro constitutive model of FG-SMA is established by using the theory of the mechanics of composites and the existing SMA model. With this macro constitutive model, the mechanical behavior of a FG-SMA beam composed by elastic material A and SMA subjected to pure bending is investigated. The loading processes including elastic process and phase transformation process are discussed in detail and the analytical solutions… More >

Guanghui Shi¹, Qingsheng Yang^1,2, Xiaoqiao He^3,4, Kim Meow Liew³

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.5, pp. 339-358, 2013, DOI:10.3970/cmes.2013.090.339

Abstract In order to describe the thermomechanical deformation and shape memory effect of shape memory polymers (SMPs), a three-dimensional thermomechanical constitutive model that considers elastic, viscoelastic strain and thermal expansion is proposed for isotropic SMPs. A three-dimensional finite element procedure is developed by implementing the proposed constitutive model into the user material subroutine (UMAT) in ABAQUS program. Numerical examples are used to compare it with existing experimental data in a one dimensional case and to demonstrate the thermomechanical behavior of SMPs with 3D deformation. It is shown that the present constitutive theory and the finite element More >

Yi Xiao¹, Qing H. Qin¹

CMC-Computers, Materials & Continua, Vol.34, No.2, pp. 95-115, 2013, DOI:10.3970/cmc.2013.034.095

Abstract In this paper, we propose a new approach of optical full-field measurement for displacement calculation on the surface of a cellular solid. Cell boundary points are sampled as nodes in the analysis. To find the nodal values of displacements the nodes are to be mapped onto their corresponding points in the deformed cell boundary by shape based point matching. A thin plate spline based robust point matching (TPS-RPM) approach is used instead of correlation of intensity pattern between two regions in traditional displacement measurement methods. The proposed approach involves multiple-step image processing including cell region More >

E. Ferretti

CMC-Computers, Materials & Continua, Vol.30, No.3, pp. 237-284, 2012, DOI:10.3970/cmc.2012.030.237

Abstract The procedure of the effective law outlined in this paper [Ferretti (2001); Ferretti and Di Leo (2003); Ferretti (2004b)] is an experimental procedure for identifying the constitutive law in uniaxial compression of brittle heterogeneous materials, and is based on the physical, analytical and numerical discussions about the existence or otherwise of strain-softening [Ferretti (2004a); Ferretti (2005)]. This procedure allows us to correct several incongruities that characterize the average stress versus average strain diagrams: it produces evidence against strain-softening in uniaxial compression [Ferretti (2004b)], whose existence may be questioned from a physical point of view [Ferretti… More >

B. Chen^1,2, X. Peng^1,2,3, X. Chen^1,2, J. Wang⁴, H. Wang⁴, N. Hu^1,5,6

CMC-Computers, Materials & Continua, Vol.30, No.2, pp. 145-176, 2012, DOI:10.3970/cmc.2012.030.145

Abstract A three-dimensional phenomenological model for coupled transformation and plastic behavior of shape memory alloys (SMAs) is presented. The strain is separated into elastic, thermal, transformation and plastic strain parts, and two yield functions are adopted to describe respectively the transformation and plastic deformation. An integral algorithm is suggested, including the update of the stress and the tangent stiffness. Numerical examples and the comparison with experimental results show that the proposed approach can well describe the behavior of the SMAs subjected to complicated thermal-mechanical loading, demonstrating the validity of the model in the description of the More >

D. Soares Jr.¹, V. Sladek², J. Sladek², M. Zmindak³, S. Medvecky³

CMC-Computers, Materials & Continua, Vol.27, No.2, pp. 101-127, 2012, DOI:10.32604/cmc.2012.027.101

Abstract This work proposes a modified procedure, based on analytical integrations, to analyse poroelastic models discretized by time-domain Meshless Local Petrov-Galerkin formulations. In this context, Taylor series expansions of the incognita fields are considered, and the related integrals of the meshless formulations are solved analytically, rendering a so called modified methodology. The work is based on the u-p formulation and the incognita fields of the coupled analysis in focus are the solid skeleton displacements and the interstitial fluid pore pressures. Independent spatial discretization is considered for each phase of the model, rendering a more flexible and efficient More >