Dynamic Simualtion and Performance Study of Magnetostrictive Transducers for Ultrasonic Applications

摘要

A dynamic simulation model of magnetostrictive actuators and transducers ahs been used to study the performance and thermal balance of an ultrasonic magnetostrictive power transducer. electrically resistive, eddy current, mechancially resistive and hysteresis losses have been deduced when the transducer works agasinst a purely mechanically resistive load for a moderate driving current of 10 A and a frequency of 21 kHz. The eddy current losses can be reduced significantly by laminating the active material. However, the hysteresis losses are the main source for heating the tranducers. Teh power losses obtained fro mthe dynamci simualtions have been used as thermal sources in electro-thermal finite element calcualtions. The calculations show that free air convection is not enough to cool the actuator. Water cooling of the actuator with a flow of 6.8 l/min will decrease the active materials temperature to around 80 deg C. This has been obtained by estiamting the heat transfer and use the heat flow as sinks in the finite element calcualtions. The design of a magnetostrictive ultrasonic transducer must therefore comprise an optimal working point regarding magnetic biasing and mechancial pre-stress to minimize the hysteresis.