| The theory of elastic wave has a vital significance for the development of non destructive detection technique in structural engineering. Dynamic stress concentration problem caused by a defect in anti-plane motion of an concrete shell can be treated as scattering problem of circular cylindrical cavity with SH guided wave in an elastic strip to be analyzed.This paper is divided into two parts.The analytical method is applied to study the problem in the first part .Firstly, compatible guided wave is formulated in the elastic strip, which is satisfied to stress free conditions in upper and lower bounds. Secondly,scattering wave of circular cylindrical cavity is expressed as series form by employed wave function expansion method,compatible scattering guided wave resulted by reflected waves of bounds of the elastic strip is constructed by using repeated images method. Lastly, coefficients of wave function expansion are determined by stress free condition of circular cylindrical bound with pregiven incident guided wave.Numerical calculating examples are presented to solve scattering of circular cylindrical cavity with given SH guided wave, to describe dynamic stress distribution of edge of cavity, to discuss influences of guided orders, frequencies and positions of cavity.In the second part,a concrete instance model is given whose physical parameters come for the C30 concrete which is widely used in the engineering. Various parameters were determined according to the basic principle of the finite element method, includes the loading mode, the boundary condition of the model, the finite element size, and the integration time step.The analytical method and numerical method are respectively applied to solve the problem and the analysis result of the two data are compared with each other in the finally end.This paper can rich the study of the anti-plane strain problem in elastic dynamics problem and provide the theoretical basis for the development of structure detection technology. |
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