Edmund Chadwick¹, Apostolis Kapoulas

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.4, pp. 331-343, 2014, DOI:10.3970/cmes.2014.102.331

Abstract Boundary element models in inviscid (Euler) flow dynamics for a manoeuvring body are difficult to formulate even for the steady case; Although the potential satisfies the Laplace equation, it has a jump discontinuity in twodimensional flow relating to the point vortex solution (from the 2π jump in the polar angle), and a singular discontinuity region in three-dimensional flow relating to the trailing vortex wake. So, instead models are usually constructed bottom up from distributions of these fundamental solutions giving point vortex thin body methods in two-dimensional flow, and panel methods and vortex lattice methods in three-dimensional flow amongst others. Instead,… More >

Xiyong Huang¹, M. H. Aliabadi², Z. Sharif Khodaei³

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.4, pp. 291-330, 2014, DOI:10.3970/cmes.2014.102.291

Abstract In this paper, a stochastic dual boundary element formulation is presented for probabilistic analysis of fatigue crack growth. The method involves a direct differentiation approach for calculating boundary and fracture response derivatives with respect to random parameters. Total derivatives method is used to obtain the derivatives of fatigue parameters with respect to random parameters. First- Order Reliability Method (FORM) is applied to evaluate the most probable point (MPP). Opening mode fatigue crack growth problems are used as benchmarks to demonstrate the performance of the proposed method. More >

Akpofure E. Taigbenu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.4, pp. 271-289, 2014, DOI:10.3970/cmes.2014.102.271

Abstract The solutions to inverse heat conduction problems (IHCPs) are provided in this paper by the Green element method (GEM), incorporating the logarithmic fundamental solution of the Laplace operator (Formulation 1) and the timedependent fundamental solution of the diffusion differential operator (Formulation 2). The IHCPs addressed relate to transient problems of the recovery of the temperature, heat flux and heat source in 2-D homogeneous domains. For each formulation, the global coefficient matrix is over-determined and ill-conditioned, requiring a solution strategy that involves the least square method with matrix decomposition by the singular value decomposition (SVD) method, and regularization by the Tikhonov… More >

Y.C. Shiah¹, Chung-Lei Hsu¹, Chyanbin Hwu^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.4, pp. 257-270, 2014, DOI:10.3970/cmes.2014.102.257

Abstract As has been well documented for the boundary element method (BEM), a volume integral is present in the integral equation for thermoelastic analysis. Any attempt to directly integrate the integral shall inevitably involve internal discretization that will destroy the BEM’s distinctive notion as a true boundary solution technique. Among the schemes to overcome this difficulty, the exact transformation approach is the most elegant since neither further approximation nor internal treatments are involved. Such transformation for 2D anisotropic thermoelasticity has been achieved by Shiah and Tan (1999) with the aid of domain mapping. This paper revisits this problem and presents a… More >

V. Giusti ¹, B. Montagnini ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.3, pp. 229-255, 2014, DOI:10.3970/cmes.2014.102.229

Abstract An application of a 3D Boundary Element Method (BEM), coupled with the Response Matrix (RM) technique, to solve the neutron diffusion and transport equations for multi-region domains is presented. The discussion is here limited to steady state problems, in which the neutrons have a wide energy spectrum, which leads to systems of several diffusion or transport equations. Moreover, the number of regions with different physical constants can be very large. The boundary integral equations concerning each region are solved via a polynomial moment expansion and, taking advantage of suitable recurrence formulas, the multi-fold integrals there involved are reduced to single… More >

E.F. Fontes Jr¹, J.A.F. Santiago¹, J.C.F. Telles¹

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.3, pp. 211-228, 2014, DOI:10.3970/cmes.2014.102.211

Abstract An iterative coupling procedure using different meshless methods is presented to solve linear elastic fracture mechanic (LEFM) problems. The domain of the problem is decomposed into two sub-domains, where each one is addressed using an appropriate meshless method. The method of fundamental solutions (MFS) based on the numerical Green’s function (NGF) procedure to generate the fundamental solution has been chosen for modeling embedded cracks in the elastic medium and the meshless local Petrov-Galerkin (MLPG) method has been chosen for modeling the remaining sub-domain. Each meshless method runs independently, coupled with an iterative update of interface variables to achieve the final… More >

L. Rodríguez-Tembleque¹, M.H. Aliabadi²

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.3, pp. 183-210, 2014, DOI:10.3970/cmes.2014.102.183

Abstract This work presents new contact constitutive laws for friction and wear modelling in fiber-reinforced plastics (FRP). These laws are incorporated to a numerical methodology which allows us to solve the contact problem taking into account the anisotropic tribological properties on the interfaces. This formulation uses the Boundary Element Method for computing the elastic influence coefficients. Furthermore, the formulation considers micromechanical models for FRP that also makes it possible to take into account the fiber orientation relative to the sliding direction, the fiber volume fraction, the aspect ratio of fibers, or the fiber arrangement. The proposed contact and wear laws, as… More >

Xiaomin Wang^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.2, pp. 169-182, 2014, DOI:10.3970/cmes.2014.102.169

Abstract In this paper, an efficient and robust wavelet Laplace inversion method of solving the fractional differential equations is proposed. Such an inverse function can be applied to any reasonable function categories and it is not necessary to know the properties of original function in advance. As an example, we have applied the proposed method to the solution of the Bagley–Torvik equations and Numerical examples are given to demonstrate the efficiency and accuracy of the proposed. More >

Z.W. Wu¹, J.K. Liu¹, Z.Q. Liu^1,2, Z.R. Lu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.2, pp. 149-168, 2014, DOI:10.3970/cmes.2014.102.149

Abstract This paper presents numerical analysis for the mooring system with nonlinear elastic mooring cables. The equation of motion for nonlinear elastic mooring cable is established by utilizing finite element method. A marine mooring system of floating rectangular box with nonlinear elastic cables is taken as an illustrative example. The dynamic analysis, static analysis, and uniformity analysis are carried out for the polyester mooring system and the results are compared with those of the steel wire and the chain mooring system. Results from the present study can provide valuable recommendations for the design and construction of the mooring system with nonlinear… More >

Jizeng Wang^1,2, Lei Zhang¹, Youhe Zhou¹

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.2, pp. 127-148, 2014, DOI:10.3970/cmes.2014.102.127

Abstract In this paper, we propose an efficient wavelet method for numerical solution of nonlinear integral equations with singular kernels. The proposed method is established based on a function approximation algorithm in terms of Coiflet scaling expansion and a special treatment of boundary extension. The adopted Coiflet bases in this algorithm allow each expansion coefficient being explicitly expressed by a single-point sampling of the function, which is crucially important for dealing with nonlinear terms in the equations. In addition, we use the technique of integration by parts to transform the original integral equations with non-smooth or singular kernels into regular ones… More >