Dynamic fracture behavior of a crack in the bulk superconductor under electromagnetic force

• Dynamic fracture behaviour of a crack in the bulk superconductor is studied.
• The dynamic strain energy release rate for superconductor is considered.
• The change of dynamic strain energy release rate with frequency is obvious.
• The crack length has different effects on the edge crack for field and current.

As the high temperature superconductors are under the electromagnetic field, large Lorentz body force can lead to the cracking of the superconductors. In the present paper, the dynamic fracture behavior of the crack in the bulk superconductor is investigated. We consider the central crack case and edge crack case. It is assumed that bulk superconductor is long enough and the demagnetization effect is neglected. By using the nonlinear constitutive relation in superconductor, the time-dependent Lorentz body force can be obtained. Then, the dynamic strain energy release rates are presented as the superconductor is under the magnetic field or with transport current. The results show that the dynamic strain energy release rates are also the periodic functions of time. The variations of dynamic strain energy release rate with edge crack length are different for the magnetic field and transport current cases.