We compare several local absorbing boundary conditions for solving the Helmholtz equation, by a finite difference or finite element method, exterior to a general scatterer. These boundary conditions are imposed on an artificial elliptical or prolate spheroid outer surface. In order to compare the computational solution with an analytical solution, we consider, as an example, scattering about an...

This paper presents a finite element formulation for the dynamics analysis of the steady and transient states of a nonlinear piezoelectric beam. A piezoelectric beam with damping is studied under harmonic excitation. A numerical method is used for this analysis. In the paper, the central difference formula of four order is used and compared with the central difference formula of two order in th...

analysis of the stresses, displacements, and horizontal strains of the ground subsidence due to underground excavation in rocks can be accomplished by means of a hybridized higher order indirect boundary element/finite difference (be/fd) formulation. a semi-infinite displacement discontinuity field is discretized (numerically) using the cubic displacement discontinuity elements (i.e. each highe...

An iterative coupling of finite element and boundary element methods for the investigation of coupled fluid-solid systems is presented. While finite elements are used to model the solid, the adjacent fluid is represented by boundary elements. In order to perform the coupling of the two numerical methods, a successive renewal of the variables on the interface between the two subdomains is perfor...

The immersed finite element-finite difference (IFED) method is a computational approach to modeling interactions between fluid and an structure. This uses element (FE) approximate the stresses forces on structural mesh (FD) momentum of entire fluid-structure system Cartesian grid. fundamental used by this follows boundary framework for interaction (FSI), in which force spreading operator prolon...

The fast progress has been observed in the development of numerical and analytical techniques for solving convection-diffusion and fluid mechanics problems. Here, a numerical approach, based in Galerkin Finite Element Method with Finite Difference Method is presented for the solution of a class of non-linear transient convection-diffusion problems. Using the analytical solutions and the L2 and ...

This paper presents a comparison of numerical methods used to model large scale acoustic coupled fluidstructure interaction (FSI) problems for single and double-walled cylindrical shells. The finite element method (FEM) is used to model the structure while the fast multipole boundary element method (FMBEM) is used to model the fluid domain and both models are coupled on the shared boundary surf...

background : near infrared spectroscopy imaging is one of the new techniques used for investigating structural and functionality of different body tissues. this is done by injecting light into the medium and measuring the photon intensity at the surface of the tissue. method : in this paper the different medical applications, various imaging and simulation techniques of nirs imaging is describe...

all the producing and assembling processes exert residual stress on the pieces that may lead to structural failure. therefore, calculating the residual stress in such structures has been common in recent years. in this article, distribution of temperature and residual stress resulting from arc welding in three-pass butt joint in p91 austenitic stainless steel pipes is calculated and estimated u...