Design And Accomplish Of SR-DF System In The Novel Passive Locating System

The present thesis investigates the scattering problems and the dynamic stress concentration problems of SH-wave by ellipse cavities in near field by the method of FEM. The FEM is a method of which transform the partial differential-coefficient equation's initial and boundary value issue to ordinary differential-coefficient equation's initial and boundary value problem (after space disperse) or a set of regular algebra equation. Then, use the direct integral calculus method of NEWMARK to solve solution, and get each node and element's displacement and stress solution vs. time. There are two problems in simulating SH-wave issue by finite element method. The first is establishing artificial boundary problem, because of simulating the infinite field from the finite field in which intercept from the infinite field, so we introduce artificial boundary. The second is solving all kinds of disadvantageous influence in space-time dispersing to reduce error. In additional, the problems of load's infliction and model's size should be considered. In this article, we found the finite element model in allusion to the problem above, solved the equation by the general finite element analysis software ANSYS, gave some node's displacement and stress solution vs. time and the dynamic stress concentration at the edge of cavity, discussed the result. Our analytic works in concrete are mainly as follows:Scattering of dynamic SH-wave and dynamic stress concentration problem are investigated by eccentric and double elliptical cavities in the whole space. The error and solution bringing from finite element disperse are expatiated. The finite element model and result are given. The present thesis discussed: displacement and accelerated speed of the model nodal points are calculated. Displacement and accelerated speed of the model nodal points which are eccentric and double elliptical, variation of the dynamic stress concentration coefficient, the displacement variable curve respectively when eccentric aperture ratios are different and when distance of the double circle cavities is different.