Creep–Cyclic Plasticity and Damage Assessment of an SS304 Weldolet

Abstract

Creep-fatigue and creep-ratcheting life assessment of an SS304 weldolet considering full creep-cyclic plasticity interaction is investigated using the extended Direct Steady Cycle Analysis (eDSCA) within the Linear Matching Method Framework (LMMF). The creep behaviour is modelled using the Norton relationship, which is modified by the Arrhenius rule to account for the temperature variation within the weldolet. The introduction of a creep dwell increases the reverse plasticity resulting from the creep relaxation. This leads to both creep-fatigue and creep-ratcheting damage mechanisms at different regions within the weldment. For thermal load dominated loading combinations, creep ratcheting due to both cyclically enhanced creep and creep enhanced plasticity are observed based on the dwell period. The effect of dwell period, load and temperature on the creep-fatigue and creep-ratcheting interaction of a weldolet are presented. The simultaneous presence of various damage mechanisms at different locations within the weldment highlights the importance and requirement of the proposed creep-cyclic plasticity investigations at weld locations.