MEASUREMENTS OF ELASTIC-WAVES IN STEEL-RO DS AND ROCK RODS USING THE MAGNETOELASTIC EFFECT

Stress waves in steel and iron ore rods produced by a mechanical impac t can be measured by a sensor using the magneto-elastic effect. A dete ction of the changing magnetic flux is made. The function describing t he propagation of longitudinal waves in rods is known as the stress wa ve equation. The agreement with theory is verified by examinations of steel rods using strain gauges. Afterwards the signals of three iron o res (magnetite, hematite, siderite) are recorded. Induced voltage is m easured by the magneto-elastic sensor in the case of magnetite and hem atite, however it is not possible to detect any signal for siderite. T his means that the change of magnetic flux depends on the kind of bulk magnetic appearance, not on content of iron. Using the magneto-elasti c sensor the magneto-elastic effect offers the possibility to detect f ree of contact mechanical waves produced by a mechanical impact in fer ro-or ferrimagnetic solids.