G. Savaidis¹, M. Malikoutsakis¹, A. Jagenbrein², A. Savaidis³, M. Soare⁴, M.V. Predoi⁴, A. Soare⁴, I.C. Diba⁴

Structural Durability & Health Monitoring, Vol.9, No.2, pp. 129-154, 2013, DOI:10.32604/sdhm.2013.009.129

Abstract Development of corrosion or/and fatigue crack propagation are the most common causes of structural degradation in road and railway tank vessels. An acoustic emission based monitoring procedure in conjunction with follow-up nondestructive testing is here proposed as a promising alternative to the conventional inspection processes enabling continuous health monitoring of the tank structures. Thereby, finite element analysis taking the respective ADR and RID tank design loads into account is proposed as a capable tool to be applied in early stages of development to reveal the hot spot areas, where acoustic emission sensors have to be More >

Leiting Dong^1,2, Satya N. Atluri^1,3

CMC-Computers, Materials & Continua, Vol.33, No.2, pp. 111-154, 2013, DOI:10.3970/cmc.2013.033.111

Abstract In this study, SGBEM Voronoi Cells (SVCs), with each cell representing a grain of the material at the micro-level, are developed for direct micromechanical numerical modeling of heterogeneous composites. Each SVC can consist of either a (each with a different) homogenous isotropic matrix, and can include micro-inhomogeneities such as inclusions, voids of a different material, and cracks. These inclusions and voids in each SVC can be arbitrarily-shaped, such as circular, elliptical, polygonal, etc., for 2D problems. Further, the cracks in each SVC can be fully-embedded, edge, branching, or intersecting types, with arbitrary curved shapes. By… More >

Y.C. Shiah¹, C.L. Tan², Y.H. Chen³

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.4, pp. 243-257, 2013, DOI:10.3970/cmes.2013.096.243

Abstract The present authors have recently proposed an efficient, alternative approach to numerically evaluate the fundamental solution and its derivatives for 3D general anisotropic elasticity. It is based on a double Fourier series representation of the exact, explicit form of the Green’s function derived by Ting and Lee (1997). This paper reports on the successful implementation of the fundamental solution and its derivatives based on this Fourier series scheme in the boundary element method (BEM) for 3D general anisotropic elastostatics. Some numerical examples of stress concentration problems and a crack problem are presented to demonstrate the More >

Changqing Miao¹, Yintao Wei², Xiangqiao Yan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.95, No.6, pp. 519-534, 2013, DOI:10.3970/cmes.2013.095.519

Abstract By using a hybrid displacement discontinuity method, the interactions of three parallel square-hole cracks in an infinite plate subjected to internal pressure are investigated in this paper. Numerical examples are included to illustrate that the numerical approach is very simple and effective for calculating the stress intensity factors (SIFs) of complex plane crack problems. Many numerical results of the SIFs are given and discussed. It is found that a square hole has a shielding effect on crack(s) emanating from the hole. The finding perhaps has an important meaning in engineering. More >

Hongtao Wang^1,2, Haitao Wang², Lie Jin², Zhenhan Yao³

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.6, pp. 529-552, 2013, DOI:10.3970/cmes.2013.094.529

Abstract Since only the boundary of the analyzed domain needs to be discretized, the boundary element method (BEM) inherently has the advantages of solving crack problems. In this paper, a micromechanics BEM scheme is applied to determine the effective elastic moduli of three-dimensional (3-D) solids containing a large number of parallel or randomly oriented microcracks. The 3-D analyses accelerated by the fast multipole method were carried out to investigate the relations between the effective elastic moduli and the microcrack density parameter. Numerical examples show that the results agree well with the available analytical solution and known More >

E. Viola¹, F. Tornabene¹, E. Ferretti¹, N. Fantuzzi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.4, pp. 331-369, 2013, DOI:10.3970/cmes.2013.094.331

Abstract In the present paper the Generalized Differential Quadrature Finite Element Method (GDQFEM) is applied to deal with the static analysis of plane state structures with generic through the thickness material discontinuities and holes of various shapes. The GDQFEM numerical technique is an extension of the Generalized Differential Quadrature (GDQ) method and is based on the idea of conventional integral quadrature. In particular, the GDQFEM results in terms of stresses and displacements for classical and advanced plane stress problems with discontinuities are compared to the ones by the Cell Method (CM) and Finite Element Method (FEM). More >

Changqing Miao¹, Yintao Wei², Xiangqiao Yan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.1, pp. 29-52, 2013, DOI:10.3970/cmes.2013.094.029

Abstract This paper is concerned with periodic collinear circular-hole cracks in an infinite plate in tension. A numerical approach to this type of circular-hole cracks is presented. Numerical examples are included to illustrate the accuracy of the numerical approach. By means of a generalization of Bueckner's principle and by using a displacement discontinuity method, periodic collinear circular-hole cracks in an infinite plate in tension are investigated in detail by using the numerical approach. Many numerical results are given and discussed. More >

K.-C. Wu², S.-M. Huang², S.-H. Chen³

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.2, pp. 133-148, 2013, DOI:10.3970/cmes.2013.093.133

Abstract An analysis is presented for an array of collinear cracks subject to a uniform tensile stress wave in an isotropic material. An integral equation for the problem is established by modeling the cracks as distributions of dislocations. The integral equation is solved numerically in the Laplace transform domain first and the solution is then inverted to the time domain to calculate the dynamic stress intensity factors. Numerical examples of one, two, or three collinear cracks are given. The results of one or two cracks are checked to agree closely with the existing results. More >

Y.C. Cai^1,2,3, J. Wu², S.N. Atluri³

CMES-Computer Modeling in Engineering & Sciences, Vol.92, No.1, pp. 63-85, 2013, DOI:10.3970/cmes.2013.092.063

Abstract The numerical manifold method (NMM), based on the finite covers, unifies the continuum analyses and discontinuum analyses without changing a predefined mathematical mesh of the uncracked solid, and has the advantages of being concise in theory as well as being clear in concept. It provides a natural method to analyze complex shaped strong discontinuities as well as weak discontinuities such as multiple cracks, intersecting cracks, and branched cracks. However, the absence of an effective algorithm for cover generation, to date, is still a bottle neck in the research and application in the NMM. To address… More >

L. N. McCartney¹

CMC-Computers, Materials & Continua, Vol.35, No.3, pp. 183-227, 2013, DOI:10.3970/cmc.2013.035.183

Abstract Analytical stress transfer models are described that enable estimates to be made of the stress and displacement fields that are associated with fibre fractures or matrix cracks in unidirectional fibre reinforced composites. The models represent a clear improvement on popular shear-lag based methodologies. The model takes account of thermal residual stresses, and is based on simplifying assumptions that the axial stress in the fibre is independent of the radial coordinate, and similarly for the matrix. A representation for both the stress and displacement fields is derived that satisfies exactly the equilibrium equations, the required interface… More >