Dynamic Character of Failure State in Damage Accumulation Processes

An exact analytical solution of a reliability evolution equation is obtained for steady-state loading conditions. This solution is used as a Green’s function for more complicated loading. The importance of the dynamic aspects of failure conditions is revealed. The observable effects of an abrupt decrease in component reliability with a stepwise stress increase and the effects of apparent ceasing of deterioration with a stepwise stress reduction are explained. It is shown that deviations from the life fraction rule result from the combined dynamics of damage accumulation and failure processes rather than from requirements of nonlinearity of damage mechanisms with time.