By using the complex variable method and conformal mapping, the diffraction of flexural waves and dynamic stress concentrations in thick plates with a cavity have been studied. A general solution of the stress problem...By using the complex variable method and conformal mapping, the diffraction of flexural waves and dynamic stress concentrations in thick plates with a cavity have been studied. A general solution of the stress problem of the thick plate satisfying the boundary conditions on the contour of an arbitrary cavity is obtained. By employing the orthogonal function expansion technique, the dynamic stress problem can be reduced to the solution of an infinite algebraic equation series. As an example, the numerical results for the dynamic stress concentration factor in thick plates with a circular, elliptic cavity are graphically presented. The numerical results are discussed.展开更多
In this paper, the inverse problem of the medium parameters in an inhomogeneous medium is studied and a generalized ray approximate form of the total wave field is described. First, the acoustic wave equation derived ...In this paper, the inverse problem of the medium parameters in an inhomogeneous medium is studied and a generalized ray approximate form of the total wave field is described. First, the acoustic wave equation derived from the elastic wave equation is studied, the referential variables and perturbational variables are introduced, and the integral equation of the medium perturbational parameters is obtained. Then from the point of view of the local principles of the wave function in an inhomogeneous medium, a generalized ray approximate form of the total wave field in an inhomogeneous medium is described, and attention is focused on the Fredholm integral equation of the first kind. Finally, the medium parameters in half-plane are inversed. Numerical examples show when the perturbations of the medium parameters are about 0.5, this method can effectively inverse its variation. Apparently, this method is better than the conventional Born weak scattering approximation.展开更多
文摘By using the complex variable method and conformal mapping, the diffraction of flexural waves and dynamic stress concentrations in thick plates with a cavity have been studied. A general solution of the stress problem of the thick plate satisfying the boundary conditions on the contour of an arbitrary cavity is obtained. By employing the orthogonal function expansion technique, the dynamic stress problem can be reduced to the solution of an infinite algebraic equation series. As an example, the numerical results for the dynamic stress concentration factor in thick plates with a circular, elliptic cavity are graphically presented. The numerical results are discussed.
文摘In this paper, the inverse problem of the medium parameters in an inhomogeneous medium is studied and a generalized ray approximate form of the total wave field is described. First, the acoustic wave equation derived from the elastic wave equation is studied, the referential variables and perturbational variables are introduced, and the integral equation of the medium perturbational parameters is obtained. Then from the point of view of the local principles of the wave function in an inhomogeneous medium, a generalized ray approximate form of the total wave field in an inhomogeneous medium is described, and attention is focused on the Fredholm integral equation of the first kind. Finally, the medium parameters in half-plane are inversed. Numerical examples show when the perturbations of the medium parameters are about 0.5, this method can effectively inverse its variation. Apparently, this method is better than the conventional Born weak scattering approximation.
