Abstract
A computer program is developed to assess the reliability of structural members considering the deterioration of resistance due to environmental effects (random loading, fatigue, corrosion).
Markov Chain Model (MCM) is applied as the theory which governs deterioration of resistance caused by fatigue crack or corrosion damage. Stationary MCM is applied to the reliability assessment of structures in the air. Probability of existence of initial defects and the probability distribution of the defect size are considered in the initial state vector of MCM. The crack initiation and propagation processes are incorporated into the transition matrix of a single MCM. As the absorbing event (failure event) of the matrix, leak failure, plastic collapse or brittle failure from critical component is considered. In order to deal with the uncertainty due to random load, marginal integration technique is employed. Nonstationary MCM is applied to the reliability assessment of structures in corrosive environment, where the effects of corrosion fatigue properties and the reduction of plate thickness on the reliability of structures are taken into consideration.
The advantage of using MCM is that the inspection procedure can be treated easily in the analysis. In the program, effects of pre-service inspection (PSI) and periodic or non-periodic in-service inspections (ISI) on the structural reliability can be evaluated.
The program is applicable to the actual structures as a support system for fatigue design and inspection maintenance.
