Evaluation of magnetic moment intensity factors for cracked soft ferromagnetic plates using strain gages

A simple experimental procedure involving measurement of strain through strip gages with five strain sensors per strip gage, has been developed to determine magnetic moment intensity factors in different specimen geometries. Static experiments are conducted in the bore of a superconducting magnet at room temperature. Ferritic stainless steel is here used as the fixed-end through-cracked plate specimen for bending test. The experiments show the increase in the moment intensity factor with increasing magnetic field. The effect of the magnetic field on the moment intensity factor is more pronounced with increasing the crack length to specimen thickness ratio. The qualitative experimental trends are in good agreement with the theoretical model developed previously. (author)