Examples of nonlinear fracture mechanics parameters include the J-integral and the T*-integral. However, strictly speaking, the J-integral is only applicable to nonlinear elastic bodies, while the T*-integral can also be applied to other nonlinear problems. In this paper, we present the results of our study into the application of the nonlinear fracture mechanics parameters J-integral range ΔJ-integral and T*-integral range ΔT*-integral to fatigue problems caused by cyclic thermo-elastic-plastic-creep, which are highly nonlinear due to cyclic temperature fluctuations, material temperature dependence, elastic-plasticity, and creep.
HAYAMA et al. (Wed,) studied this question.