(A) practical method for evaluating stability of local structures using strain energy variation

Abstract

In this thesis, we propose a practical method to evaluate the local stability of large size structures. Local stability is assessed by investigating the second variation of the local strain energy calculated through global nonlinear finite element (FE) analysis. Unlike previous methods, complicated interactions between local and global structures are fully considered and the local FE analysis is not necessary. The computational efficiency is greatly improved by applying the model reduction method to the FE model with a large number of degrees of freedom. A great advantage is that the proposed method is simple and applicable to arbitrary parts of general structures. That is, it can be practically used by engineers in industries without much effort. The evaluation methodology is proposed and its practical effectiveness is demonstrated through several numerical examples.