Rapid Fatigue Life Prediction of Butt Joint Using Energy Dissipation

This work aims at enabling a rapid life evaluation of Q310NQL2-Q345NQR2 butt joints on the basis of energy dissipation theory within the thermodynamic framework. A Representative Volume Element (RVE) model is first introduced to characterize the energy dissipation response related to two microstructural movements, i.e., the anelastic and inelastic dissipated energy, with increasing stress amplitude. The anelastic dissipated energy is linked to recoverable microstructure motions that cause no damage to the material, while the inelastic energy dissipation is associated with non-recoverable microstructure motions resulting in damage accumulation. Sub-sequently, the damage-related inelastic energy dissipation is regarded as a valid indicator to deduce a non-linear damage evolution model. Then, a normalized damage model is developed on this basis, and this model is further expanded to quantitatively estimate the high-cycle fatigue life of specimens. Finally, the S-N curves with different probabilities are rapidly estimated by combining with the maximum likelihood method, and the estimated P -S-N curves are well validated by the tested data.