Stress Monitoring in Magnetostrictive Steels of Cylindrical Shape

In this paper we present a method to monitor stresses in magnetostrictive steels of cylindrical shape. The method is based on the magnetostrictive delay line technique. The method can provide monitoring of residual stresses as well as information on plastic deformation, by monitoring permeability and magnetostriction respectively. Monitoring of the permeability provides information on residual stresses, while monitoring of the magnetostriction offers information on both residual stresses and plastic deformation. Hysteretic effects can be monitored from the loops of permeability and magnetostriction.