Hsiu-Hung Chen^a , Yuan Zhao^b, Chung-Lung Chen^a,*

Frontiers in Heat and Mass Transfer, Vol.4, No.1, pp. 1-7, 2013, DOI:10.5098/hmt.v4.1.3004

Abstract Carbon-based materials draw more and more attention from both academia and industry: its allotropes, including graphene nanoplatlets, graphite nanoplatlets and carbon nanotubes, can readily enhance thermal conductivity of thermal interface products when served as fillers. Structuraloptimization in micro/nano-scale has been investigated and expected to finely tune the coefficient of thermal expansion (CTE) of thermal interface materials (TIMs). The capability of adjusting CTE of materials greatly benefits the design of interface materials as CTE mismatch between materials may result in serious fatigue at the interface region that goes through thermal cycles. Recently, a novel nano-thermal-interface material… More >

Cao Guohua¹, Zhu Zhencai¹, Peng Weihong², Wang Jinjie¹, Liu Zhi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.2, pp. 119-138, 2013, DOI:10.3970/cmes.2013.094.119

Abstract The single helical structure is twisted by surrounding helical units with clearance or not between two layers. In order to master the thermal expansion behavior, the theory has been developed for the analysis of these helical structures. The previously deduced linear expressions of thermal expansion coefficients for the gapless structure model (GM) is used and the analytical method is applied to the clearance structure model (CM) and clearance-gapless structure model(CGM) under two boundary conditions. For further evaluating the analytical expressions of two models, the finite element models of the single helical structure surrounding by helical… More >

Jin Li¹, De-hao Yu^{2, 3}

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.1, pp. 47-67, 2013, DOI:10.3970/cmes.2013.093.047

Abstract The composite classical trapezoidal rule for the computation of Cauchy principal value integral with the singular kernel 1/(x-s) is discussed. Based on the investigation of the superconvergence phenomenon, i.e., when the singular point coincides with some priori known point, the convergence rate of the classical trapezoidal rule is higher than the globally one which is the same as the Riemann integral for classical trapezoidal rule. The superconvergence phenomenon of the composite classical trapezoidal rule occurs at certain local coordinate of each subinterval and the corresponding superconvergence error estimate is obtained. Some numerical examples are provided More >

S. Liu¹, X. Liu², X. F. Guan³, P.F. He¹, Y. Yuan²

CMES-Computer Modeling in Engineering & Sciences, Vol.92, No.2, pp. 173-191, 2013, DOI:10.3970/cmes.2013.092.173

Abstract Early performance of mass concrete structures is very sensitive to the thermal expansion characteristics of concrete. As a kind of multi-phase composite, concrete has different material composition and microscopic configuration in different scales. Its thermal expansion coefficient (CTE) depends not only on the physical and mechanical properties of the constituents, but also on their distribution. What’s more, CTE is also time-dependent with the procedure of hydration. This research proposes a stochastic multi-scale model for analyzing CTE of concrete. In the developed model, concrete macro-scale is divided into three different levels: cement paste scale, mortar scale… More >

A.E. Martínez-Castro¹, I.H. Faris¹, R. Gallego¹

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.3, pp. 177-206, 2012, DOI:10.3970/cmes.2012.087.177

Abstract In this paper, the identification of hidden defects inside a three-dimen -sional layer is set as an Identification Inverse Problem. This problem is solved by minimizing a cost functional which is linearized with respect to the volume defects, leading to a procedure that requires only computations at the host domain free of defects. The cost functional is stated as the misfit between experimental and computed displacements and spherical and/or ellipsoidal cavities are the defects to locate. The identification of these cavities is based on the measured displacements at a set of points due to time-harmonic… More >

Cao Guohua, Li Kai, Zhu Zhencai, Peng Weihong, Mao Xianbiao

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.4, pp. 403-424, 2012, DOI:10.3970/cmes.2012.083.403

Abstract In order to master the geometric and mechanical behavior of helical structure under complicated condition such as the hoisting rope in mine shaft and the transmitting cable in electric power, the thermal expansion characteristic of single helical structure is systematically investigated under temperature effect in different layer. Linearly explicit expressions of axial strain and increment of helical angle for the helical unit of the ith layer are developed. Based on theory of curve by Love and theory of wire rope by Costello, the linearly explicit expressions of tension, torsion and bending moment of the helical… More >

Ping Hu, Yang Xia, Limin Tang

The International Conference on Computational & Experimental Engineering and Sciences, Vol.17, No.3, pp. 75-76, 2011, DOI:10.3970/icces.2011.017.075

Abstract In this paper, a modified paradigm of quasi conforming finite element method with truncated polynomial expansions of in-domain displacements and derived expansions of strains is introduced. The purpose is to improve the drawbacks of the traditional one that neglecting the connections between the components of strain and lack of principle in the process of choosing polynomial expansions. Based on the modified framework a four-node quadrilateral flat shell element with complete quadratic polynomials for membrane and bending displacement fields is developed. Numerical tests are carried out for validation of the present element. The results show that More >

Weichung Yeih, Chia-Min Fan, Zen-Chin Chang,Chen-Yu Ku

The International Conference on Computational & Experimental Engineering and Sciences, Vol.20, No.2, pp. 43-44, 2011, DOI:10.3970/icces.2011.020.043

Abstract In this paper, the Cauchy problem of the nonlinear steady-state heat conduction is solved by using the polynomial expansion method and the exponentially convergent scalar homotopy method (ECSHA). The nonlinearity involves the thermal dependent conductivity and mixed boundary conditions having radiation term. Unlike the regular boundary conditions, Cauchy data are given on part of the boundary and a sub-boundary without any information exists in the formulation. We assume that the solution for a two-dimensional problem can be expanded by polynomials as: where T is the temperature distribution, np is the maximum order of polynomial expansion,… More >

Wen-Hwa Chen^1,2, Chun-Hung Wu¹, Hsien-Chie Cheng^3,4,5

CMC-Computers, Materials & Continua, Vol.25, No.3, pp. 195-214, 2011, DOI:10.3970/cmc.2011.025.195

Abstract The study aims at investigating the linear and volumetric thermal expansion coefficients (CTEs) at temperature below the Debye temperature and phase transformation behaviors at atmospheric pressure of carbon fullerenes, i.e., C₆₀, C₇₀ and C₈₀, through a modified Nosé-Hoover (NH) thermostat method incorporated with molecular dynamics (MD) simulation. The calculated results are compared with those obtained from the standard NH and "massive" NHC (MNHC) thermostats and also with the literature experimental and theoretical data. Results show that at temperature below the Debye temperature, the CTEs of the fullerene molecules would significantly decrease with a decreasing temperature and tend… More >

Durgesh Vikram¹, Sanjay Mittal², Partha Chakroborty¹

CMES-Computer Modeling in Engineering & Sciences, Vol.79, No.3&4, pp. 237-260, 2011, DOI:10.3970/cmes.2011.079.237

Abstract A stabilized finite element formulation is presented to solve the governing equations for traffic flow. The flow is assumed to be one-dimensional. Both, PW-type (Payne-Whitham) 2-equation models and the LWR-type (Lighthill-Whitham-Richards) 1-equation models are considered. The SUPG (Streamline-Upwind/Petrov-Galerkin) and shock capturing stabilizations are utilized. These stabilizations are sufficient for the 1-equation models. However, an additional stabilization is necessary for the 2-equation models. For the first time, such a stabilization is proposed. It arises from the coupling between the two equations and is termed as IEPG (Inter-Equation/Petrov-Galerkin) stabilization. Two behavioral models are studied: Greenshields' (GS) and Greenberg's… More >