The indirect boundary element method for the Helmholtz equation in three dimensions is of great interest and practical value for many problems in acoustics as it is capable of treating infinitely thin plates and allows coupling of interior and exterior scattering problems. In the present paper we provide a new approach for treatment of boundary integrals, including hypersingular, singular, and ...

We investigate the discretization of optimal boundary control problems for elliptic equations by the boundary concentrated finite element method. We prove that the discretization error ‖u∗−u∗h‖L2(Γ) decreases like N , where N is the total number of unknowns. This makes the proposed method favorable in comparison to the h-version of the finite element method, where the discretization error behav...

In this paper, exact solution for two-plane transverse vibration analysis of axial-loaded multi-step Timoshenko rotor carrying concentrated masses is presented. Each attached element is considered to have both translational and rotational inertia. Forward and backward frequencies and corresponding modes are obtained using transfer matrix method (TMM). The effect of the angular velocity of spin,...

Several new excitation and load models are proposed for electromagnetic analysis in the context of a Galerkin-type large-domain (higherorder) boundary element method (BEM) or Method of moments for structures composed of thin wires, metallic surfaces, and imperfect inhomogeneous dielectric bodies. The models represent a natural generalization of point-delta generators and loads for wires. They a...

Boundary elements method is well-suited for computational acoustics. The main profit it brings is reduction in number of unknowns compared to FEM. However, application of BEM to sound scattering problems has shown, that this advantage is lost in case of high frequency waves. High frequencies require larger number of elements which contradicts the initial purpose of using BEM in solvers and may ...

In traditional thinking, when the elastic problems are solved, we need to repeatedly plot element grids and analyze computing results according to diverse precision requirement. Against the malpractice exists in the above process, a new method of error estimation was suggested on H-R adaptive boundary element method in this paper. Based on the discrete meshes that are generated for the process ...

Topics Direct Approach for Discrete Systems Strong and Weak Forms for One-Dimensional Problems Second order boundary value problems (1D) Scalar field problems: heat conduction, advection-diffusion Triangular elements Computer implementation Isoparametric elements Numerical integration Vector field problems: elasticity equations Beam elements Eigenvalue problems Time dependent problems Special t...

Building high-quality quadrilateral/hexahedral meshes directly from volumetric data is hard. Existing algorithms for generating meshes from volumetric data are based on primal and dual isocontouring algorithms, and current research focuses on improving the quality of such meshes. Most techniques are based on isocontouring techniques, and work by generating a grid of hexahedra on the interior/ex...

A hierarchical multilevel preconditioner is constructed for an efficient solution of a first kind boundary integral equation with the single layer potential operator discretized by a boundary element method. This technique is based on a hierarchical clustering of all boundary elements as used in fast boundary element methods. This hierarchy is applied to define a sequence of nested boundary ele...

An infinitely long hollow cylinder containing isotropic linear elastic material is considered under the effect of arbitrary boundary stress and thermal condition. The two-dimensional coupled thermoelastodynamic PDEs are specified based on equations of motion and energy equation, which are uncoupled using Nowacki potential functions. The Laplace integral transform and Bessel-Fourier series are u...