Mode I crack growth rate of a ferromagnetic elastic strip in a uniform magnetic field

The theory of ferromagnetic elastic materials of multidomain structure is applied to develop a crack growth rate equation of a finite crack in a soft ferromagnetic material under mode I tensile loading and uniform magnetic field. The plane strain and plane stress problems are considered. Dugdale’s assumption regarding the plastic zone in metals is applied to estimate the effect of yield around the crack tip. The accumulated plastic displacement criterion is used for developing a solution for the crack growth rate. Numerical values of crack growth rate are obtained for a soft ferromagnetic strip with a single-edge crack and the results are displayed graphically. Crack growth rate tests are also conducted on nickel–iron soft magnetic materials with a single-edge cracked plate specimen geometry in the bore of a superconducting magnet, and a comparison is made between numerical results and experimental data.