Plane problem of thermoelectromagnetoelasticity for multiply connected bodies

Generalized complex potentials of the plane problem of thermoelectromagnetoelasticity are introduced. Expressions for the basic characteristics of the thermoelectromagnetoelastic state, boundary conditions for the complex potentials, and the general form of these functions for a multiply connected plate are obtained. The potentials are used to solve the problem for an elliptic disk with constant temperature at the edge and a concentrated heat source at the center     

Solving the problem of linear viscoelasticity for multiply connected anisotropic plates

This paper describes the method for solving the problems of linear viscoelasticity for thin plates under the influence of bending moments and transverse forces. The small parameter method was used to reduce the original problem to a sequence of boundary-value problems solved via complex potentials of the bending theory of multiply connected anisotropic plates. The general representations of complex potentials and boundary conditions for their determination are obtained. The method for determining the stress state of the plate at any time with respect to complex approximation potentials is developed by replacing the powers of the small parameter by the Rabotnov operators. The problem of a plate with elliptical holes is solved. The numerical calculation results in the case of a plate with one or two holes are given. The variation of bending moments in time until stationary condition is reached is studied, and the influence of geometric characteristics of the plate on these variable is described.     

Degenerate scale problem for plane elasticity in a multiply connected region with outer elliptic boundary

This paper investigates the degenerate scale problem for plane elasticity in a multiply connected region with an outer elliptic boundary. Inside the elliptic boundary, there are many voids with arbitrary configurations. The problem is studied on the relevant homogenous boundary integral equation. The suggested solution is derived from a solution of a relevant problem. It is found that the degenerate scale and the non-trivial solution along the elliptic boundary in the problem are same as in the case of a single elliptic contour without voids. The present study mainly depends on integrations of several integrals, which can be integrated in a closed form.     

Degenerate scale for multiply connected Laplace problems

The degenerate scale in the boundary integral equation (BIE) or boundary element method (BEM) solution of multiply connected problem is studied in this paper. For the mathematical analysis, we use the null-field integral equation, degenerate kernels and Fourier series to examine the solvability of BIE for multiply connected problem in the discrete system. Two treatments, the method of adding a rigid body term and CHEEF concept (Combined Helmholtz Exterior integral Equation Formulation), are applied to remedy the non-unique solution due to the critical scale. The efficiency and accuracy of the two regularizations are also addressed. For simplicity without loss of generality, the eccentric case is considered to demonstrate the occurring mechanism of degenerate scale.     

Analytical formulae for source and sink flows in multiply connected domains

Analytical expressions for the complex potentials associated with irrotational incompressible flows due to a finite collection of point sources and sinks in a circular fluid region, of arbitrary finite connectivity, are derived. By the conformal invariance of the boundary value problem, the flows due to point sources and sinks in arbitrary multiply connected fluid domains are then determined up to conformal mapping. As an application of the theory, it is combined with recent results on conformal slit mappings to derive explicit formulae for the effective size of an array of holes in a screen, or grating, following considerations presented by Tuck (Adv Appl Mech 15:89–158, 1975).     

The degenerate scale problem for the Laplace equation and plane elasticity in a multiply connected region with an outer circular boundary

This paper investigates the degenerate scale problem for the Laplace equation and plane elasticity in a multiply connected region with an outer circular boundary. Inside the boundary, there are many voids with arbitrary configurations. The problem is analyzed with a relevant homogenous BIE (boundary integral equation). It is assumed that all the inner void boundary tractions are equal to zero, and tractions on the outer circular boundary are constant. Therefore, all the integrations in BIE are performed on the outer circular boundary only. By using the relation z * conjg(z) = a * a, or conjg(z) = a * a/z on the circular boundary with radius a, all integrals can be reduced to an integral for complex variable and they can be integrated in closed form. The degenerate scale a = 1 is found in the Laplace equation and in plane elasticity regardless of the void configuration.     

A method for generating irregular computational grids in multiply connected planar domains

A method for generating irregular triangular computational grids in two-dimensional multiply connected domains is described. A set of points around each body is defined using a simple grid generation technique appropriate to the geometry of each body. The Voronoi regions associated with the resulting global point distribution are constructed from which the Delaunay triangulation of the set of points is thus obtained. The definition of Voronoi regions ensures that the triangulation produces triangles of reasonable aspect ratios given a grid point distribution. The approach readily accommodates local clustering of grid points to facilitate variable resolution of the domain. The technique is generally applicable and has been used with success in computing triangular grids in multiply connected planar domains. The suitability of such grids for flow calculations is demonstrated using a finite element method for solution of the inviscid transonic flow over two- dimensional high-lift aerofoil configurations.     

Study of the plane harmonic vibrations of multiply connected plates

S. P. Timoshenko Institute of Mechanics, National Academy of Sciences of Ukraine, Kiev. Translated from Prikladnaya Mekhanika, Vol. 31, No. 12, pp. 74–80, December, 1995.     

任意多连通域网格自动生成算法及其应用

给出了一种任意平面域内三角形网格自动生成的算法。本算法是根据下面两个事实而设计出来的：１．任意平面多连通域总可以剖分成若干个三角形单元。２．平面域内的活节点数目随着单元剖分总会趋近于零。文中还介绍了几种网格性能改善的方法。整个程序结构紧凑，需要人工输入的数据量少，生成的网格质量较高，而且算法稳定性能好。