A “characteristic-strain” model for creep

Abstract

The paper describes the construction of a model of creep that is very simple to implement and lends itself to engineering applications for steady or relaxing loads. The model encompasses primary, secondary and tertiary creep behaviour without requiring separate representation of each phase. The evolution of creep strain at constant stress is described in terms of three coefficients, each of self-evident physical significance, at any given temperature. The validity of the model is demonstrated by reference to a P91 dataset and assessed statistically. The incorporation of recovery, via an additional coefficient, is described and its significance is demonstrated by reference to relaxation data.

Keywords:

• creep behaviour
• steady loads
• relaxing loads