GENERALIZED IMPERFECTION SENSITIVITY LAW FOR STRUCTURES WITH BILATERAL SYMMETRY

Abstract

The general theory of elastic stability was developed to elucidate the mechanism of the imperfection sensitive reduction of buckling strength of structures. Yet the application of this theory to real structural systems has been problematic in that they involve numerous number of initial imperfections. In order to settle this problem, we focus on the fact that, for a bilateral symmetric structure, a symmetric imperfection and an asymmetric imperfection have different imperfection sensitivities. Initial imperfections are decomposed into symmetric and asymmetric imperfections, and a generalized imperfection sensitivity law is derived through the assemblage of the influence of each symmetric and asymmetric imperfection. This law enables us to evaluate the influence of a number of initial imperfection in a systematic manner. The validity of the law is assessed through the comparison of the theoretical and actual strength of a simple four-bar truss for an ensemble of 100 random initial imperfections.