The influence of cavitation damage upon high temperature creep under stationary and non-stationary loading conditions: Part I: The model description

Abstract The object of this investigation is the description of the high temperature plastic tensile behaviour of materials subjected to time variable loads. The influence of loss of load bearing capability due to cavitation damage is taken into account. In Part I a phenomenological damage model is introduced. This assumes that the damage rate A is proportional to the damage A and to the reciprocal of the lifetime function τ, respectively. The latter is derived from (static) stress rupture tests and contains the loading conditions. The basic properties of the damage function A(t) are discussed and from the model the life fraction rule (LFR) is derived. In the Parts II, III and IV the model is applied to different loading procedures. The corresponding creep equations for cavitating as well as for non-cavitating materials are derived and for the loading procedures considered the volume change during creep is calculated.