A review of creep analysis and design under multi-axial stress states

The existence of multi-axial states of stress cannot be avoided in elevated temperature components. It is essential to understand the associated ailure mechanisms and to predict the lifetime in practice. Although metal creep has been studied for about 100 years, many problems are still nsolved, in particular for those involving multi-axial stresses. In this work, a state-of-the-art review of creep analysis and engineering design s carried out, with particular emphasis on the effect of multi-axial stresses. The existing theories and creep design approaches are grouped into hree categories, i.e., the classical plastic theory (CPT) based approach, the cavity growth mechanism (CGM) based approach and the continuum amage mechanics (CDM) based approach. Following above arrangements, the constitutive equations and design criteria are addressed. In the end, hallenges on the precise description of the multi-axial creep behavior and then improving the strength criteria in engineering design are presented.