Electromagnetic Stress Analysis of High-Temperature Superconducting Coated Conductor Strip After Partial Debonding at the Edge Under the Combined Transport Current and Magnetic Field

High-temperature superconducting coated conductor strip has become a research hotspot in superconducting technology and application due to its high current transporting capacity and low ac loss. However, the problem of “edge debonding” of the coated strip seriously affects the structural stability during its application. So, in this study, the electromagnetic mechanical response of a superconducting coated conductor strip is analyzed after local debonding at the edge of the structure when it operates in a current and magnetic field environment. Based on the Bean critical state model and the Linear elasticity plane strain method, the governing equations of the normal stress in the superconducting film and the shear stress at the substrate interface are obtained. The singular points in the integral equation were eliminated through function transformation, and combined with Chebyshev polynomials, the expressions of normal stress inside the film and shear stress at the substrate interface were finally obtained. Results show that the normal stress inside the superconducting film generates a minor stress concentration near the debonding area at the edge of the structure, while the shear stress at the substrate interface shows significant stress concentration at both edges and it decreases sharply from a maximum value to zero at the debonding area. An increasing debonding width will lead to a continuous increase in normal stress in the film. The properties of the substrate material, especially the value of Young's modulus, have a significant impact on the stress inside the structure. All these factors can easily lead to degradation of the mechanical and electrical properties of superconducting tapes.