Method to determine elastic follow-Up fedict C(t) for elevated temperature structures

Abstract

This paper proposes a method to determine the elastic follow-up factors for the C(t)-integral under secondary stress. The rate of creep crack growth for transient creep is correlated with the C(t)-integral. Elastic follow-up behavior, which occurs in structures under secondary loading, prevents a relaxation of stress during transient creep. Thus, both the values of C(t) and creep crack growth increase as increasing elastic follow-up. An estimation solution for C(t) was proposed by Ainsworth and Dean based on the reference stress method. To predict the value of C(t) using this solution, an independent method to determine the elastic follow-up factors for cracked bodies is needed. This paper proposed that the elastic follow-up factors for C(t) can be determined by elastic-plastic analyses using the plastic-creep analogy. Finite element analyses were performed to verify this method. © 2012 Tne Korean society or Mechanical Engineers.