Magnetovision as a Tool for Investigation of Fatigue Process of Ferromagnetics

The study was aimed at designing a system for measuring the strength H of magnetic field surrounding a ferromagnetic specimen subjected to cyclic (or static) loading. A new type of camera for monitoring the magnetic picture of specimen was constructed. The measurement principle is based on the reverse magnetostriction effect (also called the Villari effect). No external magnetizing field is assumed; the entire magnetic effect is due sollely to cyclic mechanical loading. The measuring arrangement is best suted for examining plane stress cases. The measuring set—up is made up a precision computer controlled X–Y positioner and a basis unit whose main element is a single magnetoresistor or an array of magnetoresistors. A digital processing system yields a quasi-continuous magnetic image of an object.