APPLICATION OF PIEZO-MAGNETISM FOR THE MEASUREMENT OF STRESS DURING AN IMPACT

Ludovic Lollioz – Stéphane Pattofatto – Olivier Hubert

   This paper presents the basic of a research program whose final aim is to propose of a new kind of stress sensor for Hopkinson bar apparatus. The measurement is an electromotive force-induced signal due to the piezo-magnetic property of the material constitutive of the Hopkinson bar. The calculation of stress requires the construction of an explicit model of the magneto-mechanical behavior, based on a microscopic description. Magnetostrictive quasi-static behavior is modeled first. Magnetization quasi-static behavior is then written thanks to a thermodynamic coupling relation. The stress is estimated from emf signal through an inverse identification procedure. Amplitudes are nevertheless too low because dynamic magnetic phenomena are neglected in the modeling at present.

Keywords: piezo-magnetism, magneto-elastic coupling, dynamic tests, stress sensor

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