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 >

W. Kaewjuea¹, T. Senjuntichai², R.K.N.D. Rajapakse³

CMES-Computer Modeling in Engineering & Sciences, Vol.101, No.3, pp. 207-228, 2014, DOI:10.3970/cmes.2014.101.207

Abstract Dynamic response of an infinite cylindrical borehole in a poroelastic medium with an excavation disturbed zone is investigated in this paper. The borehole is subjected to axisymmetric time-harmonic loads and fluid sources applied to its surface, which is either fully permeable or impermeable. The governing equations based on Biot’s poroelastodynamics theory are solved by using two scalar potentials and two vector potentials. The general solutions are then derived through the application of Fourier integral transform with respect to the vertical coordinate. An exact stiffness matrix scheme is established from the derived general solutions to include the excavation disturbed zone. Boundary… More >

Yuan Li¹, Jianming Zhang^1,2, Guizhong Xie¹, Xingshuai Zheng¹, Shuaiping Guo¹

CMES-Computer Modeling in Engineering & Sciences, Vol.101, No.3, pp. 187-206, 2014, DOI:10.3970/cmes.2014.101.187

Abstract In this paper, a time-domain boundary element method formulation for the analysis of three-dimensional elastodynamic problems with arbitrary, non-null initial conditions is presented. The formulation is based on the convolution quadrature method, by which the numerical stability is improved significantly. In order to take into account the non-null initial conditions in this formulation, a general method is developed to replace the initial conditions by equivalent pseudo-forces based on the pseudo-force method. The original governing equation is transformed into a new one subjected to null initial conditions. In the numerical examples, longitudinal vibrations of a free beam and a cantilevered beam… More >

Soleiman Ghouhestani¹, Farzad Shahabian¹, Seyed Mahmoud Hosseini^2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.100, No.4, pp. 295-321, 2014, DOI:10.3970/cmes.2014.100.295

Abstract In this paper, the meshless local Petrov-Galerkin (MLPG) method is exploited for dynamic analysis of functionally graded nanocomposite cylindrical layered structure reinforced by carbon nanotube subjected to mechanical shock loading. The carbon nanotubes (CNTs) are distributed across radial direction on thickness of cylinder, which can be simulated by linear and nonlinear volume fraction. Free vibration and elastic wave propagation are studied for various value of volume fraction exponent at various time intervals. The layered cylinder is assumed to be under axisymmetric and plane strain conditions. Four types of CNTs distributions including uniform and three kinds of functionally graded distributions along… More >

T.A. Elgohary^1,2, L. Dong³, J.L. Junkins^2,4, S.N. Atluri^1,4

CMES-Computer Modeling in Engineering & Sciences, Vol.100, No.3, pp. 249-275, 2014, DOI:10.3970/cmes.2014.100.249

Abstract In this study, we consider Initial Value Problems (IVPs) for strongly nonlinear dynamical systems, and study numerical methods to analyze short as well as long-term responses. Dynamical systems characterized by a system of second-order nonlinear ordinary differential equations (ODEs) are recast into a system of nonlinear first order ODEs in mixed variables of positions as well as velocities. For each discrete-time interval Radial Basis Functions (RBFs) are assumed as trial functions for the mixed variables in the time domain. A simple collocation method is developed in the time-domain, with Legendre-Gauss-Lobatto nodes as RBF source points as well as collocation points.… More >

Cheng-Yu Ku¹

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.6, pp. 409-434, 2013, DOI:10.3970/cmes.2013.096.409

Abstract This paper proposes a novel method, named the dynamical Jacobianinverse free method (DJIFM), with the incorporation of a two-sided equilibrium algorithm for solving ill-conditioned systems of linear equations with extreme physical property contrasts. The DJIFM is based on the construction of a scalar homotopy function for transforming the vector function of linear or nonlinear algebraic equations into a time-dependent scalar function by introducing a fictitious time-like variable. The DJIFM demonstrated great numerical stability for solving linear or nonlinear algebraic equations, particularly for systems involving ill-conditioned Jacobian or poor initial values that cause convergence problems. With the incorporation of a newly… More >