激光冲击海缆软接头拉伸疲劳性能研究OA

Aimed at the problem that the joint area of copper conductors in submarine cable flexible joints is prone to fracture fatigue failure,the effects of laser shock peening(LSP)on the tensile and fatigue properties of copper conductors in submarine cable flexible joints are investigated.The self-developed laser shock peening equipment is utilized to subject the joint area to laser shock treatment at different energy levels.Tensile and fatigue tests are then performed on the treated specimens.The surface microhardness,residual stress distribution,tensile properties,fatigue life,and evolution of the fracture microstructure are measured respectively.The results indicate that the microhardness and static mechanical properties of the welded joint are significantly enhanced by laser shock treatment,while the surface stress state is improved.A substantial increase in fatigue life is also achieved.After laser shock peening at 3.5 J,the surface microhardness in the weld zone is increased by approximately 40.6%compared to the untreated specimen,and the residual tensile stress is transformed into residual compressive stress.The tensile strength of the joint is enhanced to 264 MPa,while the yield strength reaches 228 MPa.At a stress level of 113 MPa,the fatigue life is improved by up to 176.2%.Simultaneously,the microscopic mechanism by which laser shock peening enhances fatigue performance is revealed.The synergistic effect between the gradient microstructure induced by laser shock and the high-magnitude residual compressive stress introduced by laser shock peening effectively suppresses crack initiation and delays crack propagation,thereby significantly enhancing the comprehensive mechanical properties and fatigue life of the copper conductor welded joint.