Yi W. Wan¹, Huan J. Keh²

CMES-Computer Modeling in Engineering & Sciences, Vol.74, No.2, pp. 109-138, 2011, DOI:10.3970/cmes.2011.074.109

Abstract The steady rotation of an axially symmetric particle about its axis of revolution normal to two plane walls at an arbitrary position between them in a viscous fluid is studied theoretically in the limit of small Reynolds number. The fluid is allowed to slip at the surface of the particle. A method of distribution of a set of spherical singularities along the axis of revolution inside a prolate particle or on the fundamental disk within an oblate particle is used to find the general solution for the fluid velocity distribution that satisfies the boundary conditions… More >

A. A. Abdulrazeg¹, J. Noorzaei^1,2, P. Khanehzaei¹, M. S. Jaafar¹, T. A. Mohammed¹

CMES-Computer Modeling in Engineering & Sciences, Vol.68, No.3, pp. 239-268, 2010, DOI:10.3970/cmes.2010.068.239

Abstract Development of temperature rise in massive concrete structure such as a roller compacted concrete dam is attributed to hydration of concrete and environmental boundary conditions. These thermal changes in the material affect the elastic, creep properties of the material, and in turn, the stress fields within the structure. Therefore, the effects of temperature on the properties of RCC materials( elastic, creep) has to be taken into account in order to determine the risk of the thermally induced cracking in these dams. In the present work an attempt has been made to consider the effect of More >

D. C. C. Lam¹, L-H Keung¹, P. Tong²

CMES-Computer Modeling in Engineering & Sciences, Vol.66, No.1, pp. 73-100, 2010, DOI:10.3970/cmes.2010.066.073

Abstract Additional molecular rotations in long chained macromolecules lead to additional size dependence. In this investigation, we developed the higher order viscoelasticity framework and conducted experiments to determine the higher order material length scale parameters needed to describe the higher order viscoelastic behavior in the new framework. In the first part of the investigation of high order deformation behavior of macromolecular solids, the higher-order viscoelasticity theories for Maxwell and Kelvin-Voigt materials, and models of higher-order viscoelastic beam deflection creep are developed in this study. We conducted creep bending experiments with epoxy beams to show that the… More >

Huan J. Keh¹, Yu C. Chang²

CMES-Computer Modeling in Engineering & Sciences, Vol.62, No.3, pp. 225-254, 2010, DOI:10.3970/cmes.2010.062.225

Abstract A theoretical study of the Stokes flow caused by a rigid particle of revolution translating axisymmetrically perpendicular to two parallel plane walls at an arbitrary position between them in a viscous fluid, which may slip at the particle surface, is presented. A method of distribution of a set of spherical singularities along the axis of revolution within a prolate particle or on the fundamental plane within an oblate particle is used to find the general solution of the fluid velocity field that satisfies the boundary conditions at the plane walls and at infinity. The slip… More >

Yi W. Wan¹, Huan J. Keh²

CMES-Computer Modeling in Engineering & Sciences, Vol.53, No.1, pp. 73-94, 2009, DOI:10.3970/cmes.2009.053.073

Abstract The problem of the rotation of a rigid particle of revolution about its axis in a viscous fluid is studied theoretically in the steady limit of low Reynolds number. The fluid is allowed to slip at the surface of the particle. A singularity method based on the principle of distribution of a set of spherical singularities along the axis of revolution within a prolate particle or on the fundamental plane within an oblate particle is used to find the general solution for the fluid velocity field that satisfies the boundary condition at infinity. The slip… More >

FU Zhiliang¹, GUO Hua², GAO Yanfa³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.5, No.3, pp. 145-156, 2008, DOI:10.3970/icces.2008.005.145

Abstract This paper is focused on the micro-damage evolution properties of gray green mudstone under impacting disturbance load conditions for the first time by using the real time CT testing technique. CT images and CT values for rock cross-sections under different impacting disturbance loading levels were obtained. The paper is also to describe process of rock creep damage under disturbance loads and to explore the mechanism of micro-damage. The results have shown that rock failure is easy to happen suddenly rock is in or close to limit strength neighborhood during the process of disturbance. This will More >

E. Ferretti¹, A. Di Leo¹

CMC-Computers, Materials & Continua, Vol.7, No.2, pp. 59-80, 2008, DOI:10.3970/cmc.2008.007.059

Abstract The main assumption on the basis of the identifying model of the effective law, developed by the Author, is the impossibility of considering the specimen as a continuum, when an identifying procedure from load-displacement to stress-strain in uniaxial compression is attempted. Actually, a failure mechanism with propagation of a macro-crack was found to activate from the very beginning of the uniaxial compression test forth. This leads to considering the acquired displacements as composed by two quotes: one constitutive, due to the material strain, and one of crack opening. Since the ratio between these two quotes… More >

Kamran Nikbin¹

Structural Durability & Health Monitoring, Vol.3, No.1, pp. 51-68, 2007, DOI:10.3970/sdhm.2007.003.051

Abstract Weldments and welded regions of components are likely to see failure at elevated temperatures earlier than homogenous parent material. In some cases variable loading could also introduce creep/fatigue crack growth. These weld regions not only contain variable creep properties but are likely to contain residual stresses which could relax in time. There are three key factors which may determine a successful outcome for remaining life assessment of engineering components containing residual stresses in the vicinity of welds. The first is standardized testing and measurement procedures. The second is the development of appropriate and accurate correlating… More >

J. Oh¹, N. Katsube², F.W. Brust³

CMC-Computers, Materials & Continua, Vol.6, No.3, pp. 129-158, 2007, DOI:10.3970/cmc.2007.006.129

Abstract In this paper, intergranular cavity growth in regimes, where both surface diffusion and deformation enhanced grain boundary diffusion are important, is studied. In order to continuously simulate the cavity shape evolution and cavity growth rate, a fully-coupled numerical method is proposed. Based on the fully-coupled numerical method, a gradual cavity shape change is predicted and this leads to the adverse effect on the cavity growth rate. As the portion of the cavity volume growth due to jacking and viscoplastic deformation in the total cavity volume growth increases, spherical cavity evolves to V-shaped cavity. The obtained More >

C.P. Providakis¹

Structural Durability & Health Monitoring, Vol.2, No.4, pp. 249-254, 2006, DOI:10.3970/sdhm.2006.002.249

Abstract This paper explores the concept of strain energy density rate in relation to the crack initiation in fracture analysis problems arising in creeping cracked structural components. The analysis of the components is performed by using the boundary element methodology in association with the employment of singular boundary elements for the modeling of the crack tip region. The deformation of the material is assumed to be described by an elastic power law creep model. The strain energy density rate theory is applied to determine the direction of the crack initiation for a center cracked plate in More >