The optimal design and experimental verification of the bias magnet configuration of a magnetostrictive sensor for bending wave measurement

A magnetostrictive sensor has been used for the non-contact measurement of elastic stress waves in ferromagnetic waveguides. The performance of the sensor is affected significantly by the bias magnetic field applied around the sensor installation location. The objective of the present investigation is to find an optimal bias magnet configuration to maximize the sensor output for bending wave measurement. To this end, we formulate a topology design optimization problem and then find an optimal magnet or magnet-yoke configuration. In designing the configuration, the manufacturability as well as the performance of the sensor is considered. To check the performance of the present sensor, we fabricate a prototype based on the proposed design and carry out measurement experiments. The experiment results reveal the superior performance of the present sensor in comparison with the existing sensor. (C) 2003 Elsevier B.V. All rights reserved.