作者: Chuan Zeng Zhang, Xiao Wei Gao, Jan Sladek, Vladimir Sladek

摘要: This paper presents a fracture mechanics analysis in continuously non-homogeneous,
isotropic, linear elastic and functionally graded materials (FGMs). A meshless boundary element
method (BEM) is developed for this purpose. Young’s modulus of the FGMs is assumed to have an
exponential variation, while Poisson’s ratio is taken as constant. Since no simple fundamental
solutions are available for general FGMs, fundamental solutions for homogeneous, isotropic and
linear elastic solids are used in the present BEM, which contains a domain-integral due to the material
non-homogeneity. Normalized displacements are introduced to avoid displacement gradients in the
domain-integral. The domain-integral is transformed into a boundary integral along the global
boundary by using the radial integration method (RIM). To approximate the normalized
displacements arising in the domain-integral, basis functions consisting of radial basis functions and
polynomials in terms of global coordinates are applied. Numerical results are presented and discussed
to show the accuracy and the efficiency of the present meshless BEM.

1165

作者: Li Jun Li, Xian Yue Gang, Hong Yan Li, Shan Chai, Ying Zi Xu

摘要: For acoustic radiation of open thin-walled structure, it was difficult to analyze directly by analytical method. The problem could be solved by several numerical methods. This paper had studied the basic theory of the numerical methods as FEM (Finite Element Method), BEM (Boundary Element Method) and IFEM (Infinite Element Method), and the numerical methods to solve open structure radiation problem. Under the premise of structure-acoustic coupling, this paper analyzed the theory and flow of the methods on acoustic radiation of open structure, including IBEM (Indirect Boundary Element Method), DBEM (Direct Boundary Element Method) coupling method of interior field and exterior field, FEM and BEM coupling method, FEM and IFEM coupling method. This paper took the open structure as practical example, and applied the several methods to analyze it, and analyzed and compared the several results to get relevant conclusions.

692

作者: Hui Ming Zhao, Hui Dong Cheng, Wei Hong Peng, Zheng Zhu Dong

摘要: The precision of the solution of the interaction of ground and foundation beam with the coupling method of traditional boundary element method (BEM) and FEM is usually not very high. The direct coupling model of NBEM and FEM for solving the interaction of foundation ground and foundation beam was set up firstly. Then the loads under foundation were worked out with the direct coupling method. The comparison of results between the direct coupling method and other methods proved that precision of the solution of the direct coupling method is higher.

1729

作者: Zhong Ping Yang, Nan Cong

摘要: With the balance of elastic mechanics differential equation and basic solution(Kelvin solution) As the foundation introduced the boundary element method for calculating the stress and displacement of elastomer. With a numerical example of the algorithm proved. The results show that the method can be more accurate solving 2 D elastic stress and displacement problem.

1774

作者: Hai Hu, Xin Yue Wu, Long Ma

摘要: The common requests of the meshless interpolating functions are researched, and its construction method and procedures using the moving least squares method are introduced. The point collocation method is adopted to discretize the Kirchhoff-Helmholtz boundary integral equations into equation groups that constrained by boundary conditions. Constrained equation groups are solved by matrix-division method finally. Therefore, the discrete numeric expression of acoustic radiating and transferring model is obtained. In the example, acoustic field is calculated by the acoustic radiating and transferring model that obtained through both BMLM and BEM, and the results are contrasted between the computational values and the true values. It shows that the interpolating functions of BMLM could be built more flexible. So the accuracy of interpolation and calculation by BMLM is higher.

1942