A. T. Rhead¹, T. J. Dodwell¹, R. Butler^1,2

CMC-Computers, Materials & Continua, Vol.35, No.1, pp. 1-16, 2013, DOI:10.3970/cmc.2013.035.001

Abstract When (robotic) Automated Fibre Placement (AFP) is used to manufacture aerospace components with complex three dimensional geometries, gaps between fibre tows can occur. This paper explores the interaction under compressive load of these tow gaps with impact damage. Two coupons with different distributions of tow-gaps were impacted. Results indicated that the area of delamination is smaller for an impact directly over a tow gap where the tow gap is situated close to the non-impact face. Subsequent Compression After Impact (CAI) testing demonstrated that both the formation of sublaminate buckles and subsequent growth of delaminations is inhibited by the presence of… More >

Jia-Liang Le¹, Bing Xue¹

CMC-Computers, Materials & Continua, Vol.34, No.3, pp. 251-264, 2013, DOI:10.3970/cmc.2013.034.251

Abstract It has been recently shown that the nominal structural strength of metal-composite structures depends on the structure size, and such dependence is strongly influenced by the stress singularities. Nevertheless, previous studies only focused on structures that exhibit very strong stress singularities, which are close to the crack-like stress singularity. In the actual engineering designs, due to the mismatch of material properties and complex structural geometries, many metalcomposite structures may contain stress singularities that are much weaker than the crack-like stress singularity. This paper presents a numerical study on the size dependence of scaling of fracture of metal-composite hybrid structures for… More >

Shiv Narayan¹, Latha S.¹, R M Jha¹

CMC-Computers, Materials & Continua, Vol.34, No.2, pp. 131-142, 2013, DOI:10.3970/cmc.2013.034.131

Abstract The EM performance analysis of a multilayered metamaterial based radar absorbing structure (RAS) has been presented in this paper based on transmission line transfer matrix (TLTM) method for millimeter wave applications. The proposed metamaterial-RAS consists of cascaded DPS and MNG layers of identical configurations. It exhibits extremely low reflection (< 42 dB) at 95 GHz and absorbs more than 95% power of incident wave over the frequency range of 90.4- 100 GHz without metal backing for both TE and TM polarizations. In view of aerospace applications, the reflection, transmission, and absorption characteristics of the proposed metamaterial-RAS are also studied at… More >

Yi-Hsien Lin¹, Chien-Ching Ma^1,2

CMC-Computers, Materials & Continua, Vol.24, No.1, pp. 15-42, 2011, DOI:10.3970/cmc.2011.024.015

Abstract In this article, explicit transient solutions for one-dimensional wave propagation behavior in multi-layered structures are presented. One of the objectives of this study is to develop an effective analytical method for constructing solutions in multilayered media. Numerical calculations are performed by three methods: the generalized ray method, numerical Laplace inversion method (Durbin's formula), and finite element method (FEM). The analytical result of the generalized ray solution for multilayered structures is composed of a matrix-form Bromwich expansion in the transform domain. Every term represents a group of waves, which are transmitted or reflected through the interface. The matrix representation of the… More >

M. Al-Ajmi¹, A. Benjeddou²

CMC-Computers, Materials & Continua, Vol.23, No.3, pp. 265-286, 2011, DOI:10.3970/cmc.2011.023.265

Abstract A new discrete layer finite element (DLFE) is presented for electro-mechanically coupled analyses of moderately thick piezoelectric adaptive composite plates. The retained kinematics is based on layer-wise first-order shear deformation theory, and considers the plies top and bottom surfaces in-plane displacements and the plate transverse deflection as mechanical unknowns. The former are assumed in-plane Lagrange linear, while the latter is assumed in-plane full (Lagrange) quadratic; this results in a nine nodes quadrangular (Q9) DLFE. The latter is validated in free-vibrations, first numerically against ANSYS three-dimensional piezoelectric finite elements for a cantilever moderately thick aluminum plate with two co-localized piezoceramic patches,… 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 >

Smitha Gopinath^1,2, A. Ramach,ra Murthy¹, Nagesh R. Iyer¹

CMC-Computers, Materials & Continua, Vol.22, No.1, pp. 55-72, 2011, DOI:10.3970/cmc.2011.022.055

Abstract This paper presents the mathematical modeling techniques for nonlinear finite element analysis of RC structure to incorporate uniform corrosion effects. Effect of corrosion has been simulated as reduction in effective cross-sectional area of reinforcing bar, reduction in bonding phenomena and as reduction in material properties of reinforcing bar such as yield strength and elastic modulus. Appropriate constitutive laws for (i) corroded rebar elements and (ii) bond slip with corroded bar have been described. Procedure has been outlined to determine the global damage indicator by secant stiffness based approach. A corroded RC beam has been analysed to validate the proposed model… More >

X. H. Du¹, X. P. Shen¹

CMC-Computers, Materials & Continua, Vol.20, No.3, pp. 225-242, 2010, DOI:10.3970/cmc.2010.020.225

Abstract Aim of this paper is to estimate the integrity of liquefied natural gas (LNG) prestressed storage tank under seismic influence. The coupled Eulerian-Lagrangian (CEL) analysis technique is used to simulate the fluid-structure interaction between LNG and the cylinder of LNG prestressed storage tank. The 3-D model of LNG has been dispersed by Eulerian mesh that is different from traditional analysis method which is called the added mass method. Meanwhile, both of the 3-D models of prestressed rebar and concrete structure are dispersed by Lagrangian mesh. Following conclusions are obtained: 1) Natural frequency of the whole model has been obtained by… More >

S. N.V.R.K. Kurapati¹, Y. C. Lu¹, F. Yang²

CMC-Computers, Materials & Continua, Vol.20, No.1, pp. 1-18, 2010, DOI:10.3970/cmc.2010.020.001

Abstract The spherical indentation of elastic film /substrate structures is analyzed using the finite element method. The load-displacement curves of the film /substrate structures of various configurations are obtained and analyzed. A generalized power law relation is established, which can be used to analyze the load-displacement curve of elastic film /substrate systems under spherical indentations. The indentation load is dependent on the modulus ratio of the film to the substrate and film thickness. A semi-analytical expression for the power of the power law relation is also obtained as a function of the normalized film thickness and normalized film modulus, which can… More >

L.L. Zhu^1,2,3, X.J. Zheng^1,2

CMC-Computers, Materials & Continua, Vol.18, No.3, pp. 301-320, 2010, DOI:10.3970/cmc.2010.018.301

Abstract The phonon properties of spatially confined nanofilms under the preexisting stress fields are investigated theoretically by accounting for the confinement effects and acoustoelastic effects. Due to the spatial confinement in low-dimensional structures, the phonon dispersion relations, phonon group velocities as well as the phonon density of states are of significant difference with the ones in bulk structures. Here, the continuum elasticity theory is made use of to determine the phonon dispersion relations of shear modes (SH), dilatational modes (SA) and the flexural modes (AS), thus to analyze the contribution of stress fields on the phonon performance of confined nanofilms. Our… More >