Abstract:
A phenomenon (failure) is considered as the change of state of the system (structure) between the origin (hazard threshold) and the destination (failure) points. The survive and the lost ratios of the system characteristics (stiffness) are defined in this paper in terms of stiffness, and the survive and failure (phenomenon) functions. The phenomenon functions are defined (in turn) in terms of the system identification parameter (state variable) and two control parameters. These parameters were calibrated by mapping them on four selected key points including origin, quarter point, middle point and end points in the system behaviour space. The failure function was used as fragility function. The validity of the work was verified by comparing the results with the fragility curves of four nuclear power plant containment vessels.