Probabilistic Assessment of Failure Risk in Load-Bearing Components

Recent achievements in non-destructive testing evaluation (NDE), mainly the numerical reconstruction of ultrasonic data into flaw images, has enabled an integration of fracture mechanics concepts into the framework of global predictive methods of structural reliability. This approach is strongly influenced on the one hand by the uncertainty arising from NDE, including the human factor, and on the other hand by the statistical variation of materials strength characteristics and external loading intensity. The paper introduces a probalilistic rationale with the associated software for modelling the uncertainties interaction arising from the above mentioned sources. Emphasis is placed on the influence of defects (crack) size distribution on the structural reliability. A probabilistic sensitivity analysis is outlined and applied to the case of a storage tank failure.