TIME-VARIANT RELIABILITY OF BRITTLE STRUCTURAL SYSTEMS

This paper proposes a failure path approach for time-variant system re liability estimation of brittle structures. The significant failure se quences are identified by the branch-and-bound method, and the damage states in these sequences are grouped together into discrete damage le vels ranging from intact structure to system collapse. The grouping is based on the number of degrees of redundancy in the structure as it a ccumulates different amounts of damage. The Markov chain assumption is used to model the cumulative damage under time-varying loads. The exp ressions for transition probabilities from one damage level to another are derived. The effect of load overlapping under multiple load proce sses is investigated. The method is applicable to large structures due to the systematic failure sequence identification strategy employed. The resultant probability transition matrix is found to be more compac t and to represent the accumulation of damage better than existing met hods. Two numerical examples are used to illustrate and examine the pr oposed method.