Improvement of the Postbucklng Behavior of Imperfection-Sensitive Elastic Structures

Abstract

Many engineering structures are imperfection-sensitive. Their (initial) postbuckling behavior can be improved substantially by converting them to imperfection-insensitive structures. Such a conversion can be achieved by specific modes of stiffening of the structure. The aim of this paper is to present mathematical relations for the transition from imperfection sensitivity to insensitivity in consequence of such modes of stiffening. Koiter's initial postbuckling analysis is applied in the context of the Finite Element Method (FEM) to deduce these relations. An essential ingredient of a special form of accompanying linear eigenvalue analysis, previously used to compute estimates of stability limits, plays an important role in the derivation of these mathematical relations. The results from a numerical study performed by means of the FEM corroborate the theoretical findings.