Xiaoming Zhang¹, Jiangong Yu^1,2, Min Zhang¹, Dengpan Zhang¹

CMC-Computers, Materials & Continua, Vol.48, No.3, pp. 163-179, 2015, DOI:10.3970/cmc.2015.048.163

Abstract The characteristics of the guided waves propagation in functionally graded rods with rectangular cross-section (finite width and height) under initial stress are investigated in this paper based on Biot’s theory of incremental deformation. An extended orthogonal polynomial approach is present to solve the coupled wave equations with variable coefficients. By comparisons with the available results of a rectangular aluminum rod, the validity of the present approach is illustrated. The dispersion curves and displacement profiles of various rectangular functionally graded rods are calculated to reveal the wave characteristics, and the effects of different width to height ratios and initial stress and… More >

Qunfeng Liu^1,2, Liang Wang¹, gping Shen¹

CMC-Computers, Materials & Continua, Vol.46, No.2, pp. 105-123, 2015, DOI:10.3970/cmc.2015.046.105

Abstract Molecular dynamics simulations have been performed to investigate the effects of cross section geometry and shape on the mechanical behaviors of silicon nanowires (Si NWs) under tensile loading. The results show that elasticity of <100> rectangular Si NWs depends on their cross section aspect ratios while the elastic limits of <110> and <111> wires show geometry independence. Despite the significant influence of axial orientation, both yield stress and Young's Modulus show the remarkable shape dependence for wires with various regular cross sections. Additionally, underlying mechanism for the geometry and shape effects on mechanical behavior are discussed based on the fundamental… More >

F. Marín¹, F. Alhama¹, J.A. Moreno¹

CMC-Computers, Materials & Continua, Vol.43, No.1, pp. 1-20, 2014, DOI:10.3970/cmc.2014.043.001

Abstract The field of nanotribology in the last decades was established through the introduction of Atomic Force/Friction Force Microscopes. However, our theoretical understanding of the individual processes involved in friction force microscopy is limited. This work designs a reliable and efficient model for the stickslip phenomenon, following the rules of network simulation. The model is able to manage different types of potential between the tip and the sample surface, allowing different kinds of sample material and microscope tip properties to be simulated with only minor changes in the code. The most analysed tribological materials in technical literature are simulated to test… More >

S. Zhao¹, Zichun Yang^1,2, X. G. Zhou³, X. Z. Ling⁴, L. S. Mora⁵, D. Khoshkhou⁶, J. Marrow⁵

CMC-Computers, Materials & Continua, Vol.42, No.2, pp. 103-124, 2014, DOI:10.3970/cmc.2014.042.103

Abstract Continuous SiC fiber reinforced SiC matrix composites (SiC/SiC) have been studied and developed for high temperature and fusion applications. Polymer impregnation and pyrolysis (PIP) is a conventional technique for fabricating SiC/SiC composites. In this research, KD-1 SiC fibers were employed as reinforcements, a series of coatings such as pyrocarbon (PyC), SiC and carbon nanotubes (CNTs) were synthesized as interphases, PCS and LPVCS were used as precursors and SiC/SiC composites were prepared via the PIP method. The mechanical properties of the SiC/SiC composites were characterized. Relationship between the interphase shear strength and the fracture toughness of the composites was established. X-ray… More >

Raveendranath U. Nair, Preethi D.S, R. M. Jha

CMC-Computers, Materials & Continua, Vol.40, No.2, pp. 131-144, 2014, DOI:10.3970/cmc.2014.040.131

Abstract Controllable artificial dielectrics are used in the design of radomes to enhance their electromagnetic (EM) performance. The fabrication of such radome wall structures with controllable dielectric parameters seems to be an arduous task. Further even minor fluctuations of dielectric properties of radome wall due to fabrication uncertainties tend to result in drastic degradation of radome performance parameters. In the present work, a novel inhomogeneous radome with graded variation of dielectric parameters is proposed which limits the constraints on fabrication and facilitates excellent EM performance characteristics. This radome wall consists of five dielectric layers cascaded such that the middle layer has… More >

J. Aubry¹, P. Navarro¹, S. Marguet¹, J.-F. Ferrero¹, O. Dorival², L. Sohier³, J.-Y. Cognard³

CMC-Computers, Materials & Continua, Vol.39, No.1, pp. 21-47, 2014, DOI:10.3970/cmc.2014.039.021

Abstract In this paper a numerical model dedicated to the simulation of the mechanical behaviour of polymeric Rohacell foams is presented. The finite elements model is developed at the scale of the microstructure idealized by a representative unit cell: the truncated octahedron. Observations made on micrographs of Rohacell lead to mesh this representative unit cell as a lattice of beam elements. Each beam is assigned a brittle linear elastic mechanical behaviour in tension and an elastoplastic behaviour in compression. The plasticity in compression is introduced as a way to mimic the buckling of the edges of the cells observed in experimental… More >

L.B. Borkowski¹, K.C. Liu¹, A. Chattopadhyay¹

CMC-Computers, Materials & Continua, Vol.37, No.3, pp. 161-193, 2013, DOI:10.3970/cmc.2013.037.161

Abstract The microstructural variation in fiber-reinforced composites has a direct relationship with its local and global mechanical performance. When micromechanical modeling techniques for unidirectional composites assume a uniform and periodic arrangement of fibers, the bounds and validity of this assumption must be quantified. The goal of this research is to quantify the influence of microstructural randomness on effective homogeneous response and local inelastic behavior. The results indicate that microstructural progression from ordered to disordered decreases the tensile modulus by 5%, increases the shear modulus by 10%, and substantially increases the magnitude of local inelastic fields. The experimental and numerical analyses presented… More >

Balamati Choudhury¹, Pavani Vijay Reddy¹, Sanjana Bisoyi¹, R. M. Jha¹

CMC-Computers, Materials & Continua, Vol.37, No.3, pp. 135-146, 2013, DOI:10.3970/cmc.2013.037.135

Abstract The terahertz region of the electromagnetic spectrum plays a vital role in biomedical imaging because of its sensitivity to vibrational modes of biomolecules. Advances in broadband terahertz imaging have been emerging in the field of biomedical spectroscopy. Biomedical imaging is used to distinguish between the infected (cancer) and the non-infected tissue, which requires broad band and highly efficient radar absorbing material (RAM) designs (to obtain high resolution image of the tissue). In this paper, a metamaterial broadband RAM design is proposed towards biomedical spectroscopy applications in the THz region. The particle swarm optimization (PSO) algorithm is used for the design… More >

Raveendranath U Nair¹, R M Jha¹

CMC-Computers, Materials & Continua, Vol.37, No.2, pp. 109-121, 2013, DOI:10.3970/cmc.2013.037.109

Abstract Enhancement of electromagnetic performance of A-sandwich radome using aperture-type Jerusalem cross frequency selective surface (FSS) is presented. The Jerusalem cross FSS array is embedded in the mid-plane of the core of Asandwich radome to enhance the EM performance parameters over the entire Xband. For modeling the Jerusalem cross FSS embedded radome panel and evaluation of its EM performance parameters, equivalent transmission line method in conjunction with equivalent circuit model is used. A comparative study of Jerusalem cross FSS embedded A-sandwich radome and A-sandwich radome of identical material and thickness (core and skin layers) indicate that the new wall configuration has… More >

Leiting Dong^1,2, Salah H. Gamal³, Satya N. Atluri^2,4

CMC-Computers, Materials & Continua, Vol.37, No.1, pp. 1-21, 2013, DOI:10.3970/cmc.2013.037.001

Abstract In this paper, a simple and reliable procedure of stochastic computation is combined with the highly accurate and efficient Trefftz Computational Grains (TCG), for a direct numerical simulation (DNS) of heterogeneous materials with microscopic randomness. Material properties of each material phase, and geometrical properties such as particles sizes and distribution, are considered to be stochastic with either a uniform or normal probabilistic distributions. The objective here is to determine how this microscopic randomness propagates to the macroscopic scale, and affects the stochastic characteristics of macroscopic material properties. Four steps are included in this procedure: (1) using the Latin hypercube sampling,… More >