The Research On Ultimate Bearing Capacity And System Reliability Of Thin-Walled Structure

At the present time, reliability design of the thin-walled structure stays on point reliability step. It can't satisfy the demand of the present structure design more and more. The development of building structures puts forward new requirements to the research on reliability of thin-walled structure. To the thin-walled structure system, it can identify the safe level (reliability) of structure rationally only by the system reliability. In addition, how to use the theory of the structure system reliability on research of the thin-walled structure which can increase the reliability safety and the economical efficiency is urgent requirement too.The main contents of this paper can be summarized as follows:Firstly, a modified elastic compensation method based on a general yield rule is builded on plastic limit analysis of thin-walled structure. The elastic compensation method, based on an elastic-perfectly plastic material model, can simulate plastic failure mechanisms by adjusting the elastic modulus of each element systemically in a series of finite element model is adjusted according to the ratio of the stress in the element to nominal stress in order to redistribute the stress field away from highly stressed regions. Therefore, a series of different statically admissible stress fields are obtained in a simple and efficient way.Secondly, a method is builded on system reliability analysis of thin-walled structures.The branch-and-bound method is applied to analyse the system reliability and search the main failure modes of thin-walled structure. The reliability safety of thin-walled structure that can be proved by the Mente-Carlo method is evaluated by the height of structural system. System reliability calculated by this method can assure the mai failure modes that isn't omitted and higher accuracy.