Open Access
ARTICLE
A. Ramachandra Murthy1, G.S. Palani1, Smitha Gopinath1, V. Ramesh Kumar1, Nagesh R. Iyer1
CMC-Computers, Materials & Continua, Vol.37, No.2, pp. 77-96, 2013, DOI:10.3970/cmc.2013.037.077
Abstract This paper presents the development of an improved concrete damage model for projectile impact on concrete structural components. The improvement is in terms of reduction of input material parameters for nonlinear transient dynamic impact analysis by employing concrete damage model. The experimental data such as pressure vs volumetric strain, triaxial compression failure and pressure vs stress difference have been used for evaluation of the important parameters of concrete damage model. Various contact algorithms have been outlined briefly to model the interface between the projectile and target. The nonlinear explicit transient dynamic analysis has been carried out by using finite element… More >
Open Access
ARTICLE
Shiv Narayan1, R M Jha1
CMC-Computers, Materials & Continua, Vol.37, No.2, pp. 97-108, 2013, DOI:10.3970/cmc.2013.037.097
Abstract A novel metamaterial based FSS (frequency selective surfaces) structure is presented in this paper for wideband airborne radome applications. The proposed metamaterial-FSS structure consists of three layers, where a DPS (double positive sign) layer is sandwiched between a MNG (μ-negative) and ENG (ε- negative) layer, exhibits very good bandpass characteristics inside the operational band along with excellent roll-off characteristics outside the band. The EM performance analysis of the proposed structure has been carried out using transmission line transfer matrix (TLTM) method, which shows excellent bandpass characteristics over a wide frequency range. The transmission efficiency is over 95% both at normal… More >
Open Access
ARTICLE
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 >
Open Access
ARTICLE
Qiang Zhang, Qing-Sheng Yang1
CMC-Computers, Materials & Continua, Vol.37, No.2, pp. 123-134, 2013, DOI:10.3970/cmc.2013.037.123
Abstract In nanoindentation testing of materials, the analytical/numerical models to connect the indentation load, indentation depth and material properties are crucial for the extraction of mechanical properties. This paper studied the methods of extracting the mechanical properties of nonlinear elastic materials and built general relationships of the indentation load and depth of hyperelastic materials combined with the dimensional analysis and finite element method (FEM). Compared with the elastic contact models and other nonlinear elastic contact models, the proposed models can extract the mechanical properties of nonlinear elastic materials under large deformation simply and effectively. More >
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