Narrow Results

We have attempted to study how viscous flux flow affects the crack–inclusion interaction in a long rectangular slab of superconductor during the decreasing field stage under zero-field cooling (ZFC) magnetization process systematically. After some manipulation, the effect of viscous flux flow on the crack–inclusion problem within the superconductor is discussed base on J-integral theory. The simulated results indicate that with the increase of viscous flux flow, the stress intensity factor will increase correspondingly, but the trend of the curve with the elastic modulus, crack length and inclusion radius does not change, associated with the distance between the left crack tip and the inclusion. Compared with viscous flux flow, the effect of the crack length on crack propagation may be more significant under a lower viscous flux flow rate. However, at the higher viscous flux flow, the opposite is true.

In this paper, the magnetization and magnetoelastic behaviors of superconducting film in perpendicular external magnetic field with viscous flux flow are studied. The distribution of magnetic flux density, current density, physical strength and normal stress in the film is calculated during the increase of external magnetic field. Among others, the variations in shielding region and mechanical response with viscous magnetic flux flow are analyzed. The results indicate that the magnetization and magnetoelastic behavior in the film with viscous flu flow are different from the quasistatic critical state model, such as the origin Bean model. With the obtained results, since the film is in an external field, we can even predict the maximum probability of cracking. Similarly, it is valuable to derive the theory of magnetostriction of thin films to further popularize the method.