Research On The Effect Of Inclusions On Superconductor Magnetostriction Under Viscous Magnetic Flux

In the era of science and technology,the application of superconducting materials will be the general trend.Because of its diamagnetism and superconductivity,superconducting materials have great application value.However,in the production and preparation process of high temperature superconductors,due to technical and technological factors,it is inevitable that some defects such as inclusions and dislocations will appear.These inclusions will affect the mechanical properties of superconductors in the process of magnetization.This will affect the practical application of high temperature superconductors and reduce the practical application value of high temperature superconductors.Therefore,it is necessary to study the influence of inclusions on the mechanical behavior of high temperature superconductors.In this paper,the effects of non superconducting inclusions on the magnetostriction of bulk high temperature superconductors and the effects of magnetic inclusions on the magnetostriction of bulk high temperature superconductors under the condition of magnetic flux viscous flow are studied respectively.In the second chapter,a superconducting rectangular plate model containing a circular non-superconducting inclusion is established.By solving the flux viscous flow equation and Bean model at the same time,the analytical expressions of each stage of viscous magnetization process were obtained,and the effect of inclusion under viscous flux on magnetostriction of bulk superconductors was discussed.Then,the plane strain method was used to study the effects of different flux viscous flow rates,different volume fractions and different elastic modulus on the magnetostrictive changes of non-superconducting inclusion on the superconducting rectangular plate during zero-field cooling.In the third chapter,the influence of different permeability on the mechanical properties of cylindrical superconductors with magnetic inclusion in viscous flux flow is studied theoretically.It is found that the change of permeability,volume fraction and elastic parameters of magnetic inclusion will lead to the change of the distribution of stress and strain in the cylindrical superconductor.The displacement distribution in the superconductor was calculated according to the stress,strain and boundary conditions,and the effect of magnetic inclusion on magnetostriction of the cylindrical superconductor was further obtained.In this paper,the changes of mechanical properties caused by non-superconducting inclusions or magnetic inclusions in the magnetization process of superconducting rectangular plate and superconducting cylinder are studied and analyzed respectively.By considering the factors of magnetic flux viscous flow,some theoretical reference value is provided for the changes of mechanical properties of superconducting rectangular plate and superconducting cylinder.