Simulation framework for risk assessment of damage tolerant structures

Damage tolerant structures rely on safety by virtue of damage detection during periodic inspections and follow-up repairs. Aging structures and life extension programs need continuous monitoring for safe operation. Assuring a certain maximum risk level demands defining an inspection program for these structures in which the damage initiation, growth, detection, and tolerance are all probabilistic in nature. Fewer inspections increase the probability of failure. Over-inspecting leads to increased life cycle costs and downtime periods. This paper presents a simulation framework which can synthesize the probabilistic variations to strike a balance between desired safety levels and affordable inspection programs over a life span of a generic damage tolerant engineering structure. This novel framework can absorb virtually any mathematical or numerical model for representation of service life events; which in turn helps quantitatively assess risk, perform sensitivity analysis and resolve optimization issues related to maintenance decisions.