Low cycle fatigue behavior of zirconium-titanium-steel composite plate
(1. Engineering Technology Training Center, Nanjing Vocational University of Industry Technology, Nanjing 210023, China;
2. School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, China;
3. Jiangsu Key Lab of Design and Manufacture of Extreme Pressure Equipment, Nanjing 210028, China;
4. Technology Research and Development Department, Nanjing Boiler and Pressure Vessel Inspection Institute, Nanjing 210028, China)
2. School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, China;
3. Jiangsu Key Lab of Design and Manufacture of Extreme Pressure Equipment, Nanjing 210028, China;
4. Technology Research and Development Department, Nanjing Boiler and Pressure Vessel Inspection Institute, Nanjing 210028, China)
Abstract: 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.
Key words: zirconium-titanium-steel composite plate; low cycle fatigue behavior; fatigue damage; mean stress; ratcheting effect; life prediction model