Studying the magnetoelastic properties of a steel sheet under bending deformation

The possibility of using the method of magnetoelastic demagnetization (magnetoelastic memory) of ferromagnets to control mechanical stresses of extended steel structures is considered. For this purpose, the paper studies the magnetoelastic demagnetization of a large plate sample, previously locally magnetized in the form of an N-S stripe, under pure bending deformation. Under these deformation conditions, zones of tension and compression alternate along the sheet length; consequently, a locally magnetized steel stripe experiences stresses of different magnitudes and signs along its length. It has been revealed that the highest decrease δН in the stray field strength of local remanent magnetization in the form of an N-S stripe is found in steel sheet areas at the apex of the bend, where tensile stresses do not exceed 100 MPa. In the other parts of the sheet, a periodic distribution of lower δH with a wavelength of 20 to 30 cm was revealed, this being comparable to the size of half of its zone with stresses of the same type created during bending. The obtained results of changes in δH were calibrated according to the level of stresses they experienced, and their distribution along the entire length of the bent sheet was obtained. A conclusion is drawn about the applicability of the magnetoelastic memory method to monitoring the stress state of extended steel structures in the memory mode.