Effect of edge cracks on critical current degradation in REBCO tapes under tensile stress

作     者：Zhirong Yang Yi Li Peng Song Mingzhi Guan Feng Feng Timing Qu 

作者机构：State Key Laboratory of TribologyDepartment of Mechanical EngineeringTsinghua UniversityBeijing 100084China Department of Mechanical EngineeringAdvanced Manufacturing InstituteTexas Center for SuperconductivityUniversity of HoustonHoustonTX 77024USA Institute of Modern PhysicsChinese Academy of SciencesLanzhou 730000China Lab of Intelligent Manufacturing and Precision MachiningTsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China 

出 版 物：《Superconductivity》 (超导（英文）)

年 卷 期：2022年第1卷第1期

页      面：52-62页

学科分类：0808[工学-电气工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：the Strategic Priority Research Program of Chinese Academy of Sciences under Grant No.XDB25000000 the National Natural Science Foundation of China under Grant No.52007089. 

主　　题：REBCO Degradation Stress intensity factor Multiple oblique edge cracks Fracture toughness 

摘      要：The slitting process for manufacturing REBa2Cu3O7
δ(REBCO,RE=Rare earth)tapes of required width significantly improves the production efficiency and reduces production costs.However,edge cracks induced by the slitting process of wide REBCO tapes may cause premature degradation under high tensile stress in highfield magnets.Therefore,it is necessary to evaluate the effect of edge cracks of REBCO tapes on the critical current(Ic)degradation.Firstly,Ic degradation under artificial cracks was measured to validate the applicability of linear elastic fracture mechanics for the REBCO layer.The maximum circumferential stress criterion was used to derive the mixed-mode stress intensity factor of multiple oblique edge cracks.A semi-analytical model considering edge crack properties such as angleβ,spacing d,and length a,was built to evaluate the critical load and critical crack.We found that when the stress intensity factor at the crack tip is below KIC?2:3 MPa ffiffiffiffim p,edge cracks did not propagate.We examined commercial REBCO tapes manufactured by two different processes,concluding that edge cracks in these tapes will not cause premature degradation.