Low cycle fatigue behavior of zirconium–titanium–steel composite plate

The low cycle fatigue behavior of zirconium–titanium–steel composite plate under symmetrical and asymmetric stress control was studied. The effects of mean stress and stress amplitude on cyclic deformation, ratcheting effect and damage mechanism were discussed in detail. The results show that under symmetric stress control, the forward ratcheting deformation is observed. Under asymmetric stress control, the ratcheting strain increases rapidly with mean stress and stress amplitude increasing. Under high stress amplitude, the influence of mean stress is more significant. In addition, by studying the variation of strain energy density, it is found that the stress amplitude mainly promotes the fatigue damage, while the mean stress leads to the ratcheting damage. In addition, fracto- graphic observation shows that the crack initiates in the brittle metal compound at the interface, and the steel has higher resistance to crack propagation. Finally, the accuracy of life prediction model considering ratcheting effect is discussed in detail, and a high-precision life prediction model directly based on mean stress and stress amplitude is proposed.