Reliability analysis of damaged structures.

It has become important to evaluate the reliability of existing structures in order to establish a rational program for repair and maintenance. Since most of the existing structures may suffer from defect, corrosion and damage, it is necessary to account for their effects in the reliability analysis.In this paper, an attempt is made to develop a reliability analysis for damaged structures using fuzzy sets theory. Damage state is specified in terms of linguistic variables such as “slight”, “more or less”, “severe”, etc. which are defined by fuzzy sets. Using a fuzzy reduction factor, information of the damage state is introduced into the calculation of failure probability. A measure of structural redundancy is newly proposed based on the failure probabilities of damaged and undamaged structures. Several examples are presented to illustrate and demonstrate the applicability of the reliability analysis proposed herein.