Study On The Interaction And Fracture Behavior Of Inclusions And Cracks In Bulk Superconductors

The advent of superconductor has a history of more than one hundred years.With the continuous exploration of scientists,superconductor has made a great leap.Especially in recent decades,superconductors play an important role in production and life.Due to the high critical current density and critical temperature of high temperature superconductors,people pay more attention to them.Superconductors are also affected by magnetic flux creep,which makes the properties of superconducting materials change in the magnetic field.This article mainly studies the bulk materials of high-temperature superconductors,which have been widely used in various fields.Superconductor is a kind of brittle material.When it is in the changing external magnetic field,the electromagnetic force generated by magnetic flux pinning in superconductor is easy to make superconductor fracture,so we also need the stability and safety of superconductor.Therefore,it is of great significance to further study the crack propagation and fracture behavior in superconductors.In a word,people pay more and more attention to the research of superconductors.In this paper,the interaction between inclusions and cracks in a superconductor cylinder in an external magnetic field with variable critical current density,and the effects of viscous flow and creep of magnetic flux on a superconducting rectangular plate are studied.In the second chapter,a superconducting cylinder model with cracks and inclusions is established.By solving the exponential distribution equation of the critical current density,the influence of the inhomogeneous distribution of the critical current density index on the inclusions and cracks in the superconductor is analyzed during the field decreasing process in the zero field cooling stage,and the interaction between the cracks and inclusions in the superconductor cylinder is studied.Through the use of ABAQUS software for simulation calculation.The effects of non-uniform distribution of critical current density,length of crack,size of inclusion,elasticity and rigidity of inclusion,distance between crack and inclusion on stress intensity factor at crack tip are analyzed.In the third chapter,a plate superconductor model with a central crack is established to solve the equations of viscous flux flow and flux creep.The finite software is used to analyze the effect of different motion modes on the stress intensity factor at the crack tip,and the law of the variation of the viscous flux flow rate and flux creep rate with time.It is important for the safety of high temperature superconductors significance.In the zero-field cooling process,the effect of the viscous magnetic flux flow and the interaction with the magnetic flux creep on the stress intensity factor of the crack tip is to avoid crack propagation.