Numerical Analysis of Low-Cycle Fatigue Using the Direct Cyclic Method Considering Laser Welding Residual Stress

The sequential-coupled thermo-mechanical model and direct cyclic technique are employed to investigate laser welding and low-cycle fatigue residual stress, respectively. The effects of residual stress on fatigue properties and the relaxation behaviour are analyzed. The simulation results highlight the strong dependence of laser welding residual stress on constitutive models and how low-cycle fatigue residual stress is influenced by the initial laser welding residual stress. Furthermore, the simulation indicates that residual stress redistributes and relaxes in the weld and heat-affected zone after low-cycle fatigue. To validate the accuracy of the simulation, the neutron diffraction experiment is carried out, and the experimental data are consistent with the simulation results.

Automated summary

The study employs a sequential-coupled thermo-mechanical model and direct cyclic technique to investigate laser welding and low-cycle fatigue residual stress. The effects of residual stress on fatigue properties and relaxation behavior are analyzed. The simulation results show that laser welding residual stress is highly dependent on constitutive models and how initial laser welding residual stress influences low-cycle fatigue residual stress. Furthermore, the simulation indicates that residual stress redistributes and relaxes in the weld and heat-affected zone after low-cycle fatigue. To validate the accuracy of the simulation, neutron diffraction experiment is carried out, and the experimental data are consistent with the simulation results.