ANALYSIS OF FREE VIBRATION AND DYNAMIC RESPONSE IN THIN SHELLS BY USING GENERALIZED CONFORMING ELEMENT

摘要

In this paper,a triangular flat shell element with eighteen degrees of freedom is constructed.lt includes two parts of generalized conforming membrane element with drilling freedom and generalized conforming plate bending element.This generalized conforming triangular element could pass the patch test on arbitrary mesh subdivision and converge to the precise solution. This paper provides the displacement functions of membrane and bending parts of the flat thin triangular shell element respectively. According to some certain principles,the membrane stiffness matrix and bending stiffness matrix parts are combined into thin shell element stiffness matrix. In the same way,the combination of the element mass matrix can be obtained.By using subspace iteration method,the natural frequencies of low degrees are calculated. When we get the first and second circular frequencies,the damp matrix is also obtained.Through these characteristic matrixes,we can carry out the response analysis of spherical shells subjected to dynamic excitations,such as the horizontal and vertical earthquakes,etc. In the end of this paper,some calculating examples are given 2nd several important conclusions are obtained.