S. Liu¹, X. Liu^2,3, Y. Yuan², P. F. He¹, H. A. Mang^2,4

CMC-Computers, Materials & Continua, Vol.39, No.2, pp. 85-112, 2014, DOI:10.3970/cmc.2014.039.085

Abstract Autogenous shrinkage is defined as the bulk deformation of a closed, isothermal, cement-based material system, which is not subjected to external forces. It is associated with the hydration process of the cement paste. From the viewpoint of engineering practice, autogenous shrinkage deformations result in an increase of tensile stresses, which may lead to cracking of early-age concrete. Since concrete is a multi-phase composite with different material compositions and microscopic configurations at different scales, autogenous shrinkage does not only depend on the hydration of the cement paste, but also on the mechanical properties of the constituents and of their distribution. In… More >

Y.C. Shiah¹, Y.M. Lee², T.C. Huang²

CMC-Computers, Materials & Continua, Vol.39, No.1, pp. 49-71, 2014, DOI:10.3970/cmc.2014.039.049

Abstract A common difficulty arises in characterizing the anisotropic properties of a thin sheet of anisotropic material, especially in the transverse direction. This difficulty is even more phenomenal for measuring its mechanical properties on account of its thickness. As the prelude of such investigation, this paper proposes a novel approach to identify the thermal conductivities of an unknown thin layer of anisotropic material. For this purpose, the unknown layer is sandwiched in isotropic materials with known conductivities. Prescribing proper boundary conditions, one may easily measure temperature data on a few sample boundary points. Therefore, the anisotropic thermal conductivities can be calculated… 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 >

Satya N. Atluri¹

CMC-Computers, Materials & Continua, Vol.39, No.1, pp. 1-2, 2014, DOI:10.3970/cmc.2014.039.001

Abstract This article has no abstract. More >

J.B. Niu¹, L.L. Li², Q. Xu¹, Z.H. Xia^1,3

CMC-Computers, Materials & Continua, Vol.38, No.1, pp. 31-41, 2013, DOI:10.3970/cmc.2013.038.031

Abstract Crack deflection and penetration at the interface of multi-wall carbon nanotube/amorphous carbon composites were studied via molecular dynamics simulations. In-situ strength of double-wall nanotubes bridging a matrix crack was calculated under various interfacial conditions. The structure of the nanotube reinforcement -ideal multi-wall vs. multi-wall with interwall sp³ bonding - influences the interfacial sliding and crack penetration. When the nanotube/matrix interface is strong, matrix crack penetrates the outermost layer of nanotubes but it deflects within the nanotubes with certain sp³ interwall bond density, resulting in inner wall pullout. With increasing the sp³ interwall bond density, the fracture mode becomes brittle; the… 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 >

Ridha Djebali¹, Mohsen Toujani², Bernard Pateyron³

CMC-Computers, Materials & Continua, Vol.37, No.3, pp. 147-160, 2013, DOI:10.3970/cmc.2013.037.147

Abstract In this paper a study of the atmospheric plasma spraying process was conducted. The Jets&Poudres code was used to solve the partial differential equations for the conservation of mass, momentum and energy involved in the problem together with the K-e turbulent model. The Taguchi technique was used to study the influence of processing factors on droplet impact properties obtained on dense zirconia (ZrO₂) under H₂Ar75% plasma gas that allow optimal functioning condition. The test of the operating parameters for the studied ranges showed that the "thermal power" factor plays a key role on the state of sprayed powder. It was… 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 >

J. Joseph¹, Y. C. Lu¹

CMC-Computers, Materials & Continua, Vol.37, No.1, pp. 59-75, 2013, DOI:10.3970/cmc.2013.037.059

Abstract The aligned carbon nanotube (A-CNT) structure is composed of arrays of individual CNTs grown vertically on a flat substrate. The overall structure and properties of an A-CNTs are highly dependent upon the designs of various architectures and geometric parameters. In Part 2, we have presented the detailed designs and modeling of various aligned carbon nanotube structures. It is found the A-CNT structures generally have much lower modulus than an individual CNT. The reason is due to the high porosity and low density of the A-CNT structures, since the interstitial space between nanotubes is mostly occupied by air. Increasing the nanotube… More >

J. Joseph¹, Y. C. Lu¹

CMC-Computers, Materials & Continua, Vol.37, No.1, pp. 39-57, 2013, DOI:10.3970/cmc.2013.037.039

Abstract Aligned carbon nanotubes structures are emerging new materials that have demonstrated superior mechanical, thermal, and electrical properties and have the huge potential for a wide range of applications. In contrast with traditional materials whose microstructures are relatively "fixed", the aligned carbon nanotube materials have highly "tunable" structures. Therefore, it is crucial to have a rational strategy to design and evaluate the architectures and geometric factors to help process the optimal nanotube materials. Astructural mechanics based computational modeling is used for designing the aligned carbon nanotubes structures. Part 1 of the papers presents the theory of the computational method as well… More >