UNIAXIAL CREEP MODELLING BY CONTINUUM DAMAGE MECHANICS, CRISPEN AND THE THETA PROJECTION CONCEPT

摘要

A comparative study is conducted on three approaches to creep modelling: the phenomenological Continuum Damage Mechanics (CDM) model pioneered by Katchanov, the physically based CRISPEN model developed by NPL and Cambridge University, and the theta projection concept developed in Swansea. Strain-time relationships have been derived from constitutive equations for the CRISPEN model. A modified version of the theta curve fitting computer programme was found suitable for the estimation of the CRISPEN equation constants. These constants vary with stress and temperature in a systematic manner. The simulative and predictive capabilities of each model is then discussed and compared using constant stress uniaxial creep data for 316 stainless steel.