SAFETY OF MATERIALS AND STRUCTURES IN CREEP CONDITIONS

This paper deals with the evaluation of safety structures in creep con ditions. It appears to be a function of applied load and operation tim e, and structural analysis has to take into account both residual stre ngth reduction and time-dependent failure under constant load. The con tinuum damage mechanics that uses a new state variable associated with material deterioration was used in the analysis performed in this pap er. First, attention was paid to residual strength reduction that occu rs in any point of a structure's body, then the analysis was enhanced to cover all stages of the failure process that can be distinguished w hen structural behaviour is taken into account. Two types of structure s (trusses and plates) were chosen to demonstrate the influence of thi s effect upon life-time evaluation of structures.