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Abstract
A creep damage model from the micromechanics viewpoint is presented in the paper. In order to mitigate the difficulty of calibrating many parameters in the existing damage evolution models, a simple creep ductility exhaustion approach is employed to account for the accumulation of the creep damage. Two-dimensional and three-dimensional numerical analyses of creep crack growth based on the new creep-damage model and/or Liu-Murakami model are carried out. When the damage parameter reaches a critical value, the load carrying capacity of each damaged element approaches zero and thus crack growth can be characterised by a completely damaged element zone ahead of the initial crack tip. The finite element simulation results obtained are compared favourably with experimental data for the compact tension specimen for 316 stainless steel and bending cracked plate for T91 steel at elevated temperatures. The comparisons show the excellent capability of the proposed model in predicting the crack growth rate and progressive crack profiles. In addition, the influences of the plasticity and mesh size are discussed in this paper.
This study is funded by National Natural Science Foundation of China (contract no. 50835003) and China Scholarship Council. Numerical simulations were performed at the Supercomputing Facility at Texas A&M University. Thanks are given to Professor W. Sun and Professor T.H. Hyde at University of Nottingham and Dr Nak-Hyun Kim at Korea University for the helpful discussion with them. We also appreciate the detailed drawing sheet of the cracking plate offered by Dr Olivier Ancelet at CEA.