考虑压力变化的超磁致伸缩超声换能器动态模型

摘要

Terfenol-D is a kind of giant magnetostrictive material.It shows much deformation than other magnetic material in variable magnetic field.As active material,it is often used in giant magnetostrictive ultrasonic transducer(GMUT).However the thermal problem is a key factor which restricts power promoted for GMUT.Hysteresis losses and eddy current losses are the main source for heating the GMUT.Eddy current losses can be reduced significantly by laminating the active material and the hysteresis losses become the main thermal source in GMUT.A new method for hysteresis losses’ computation,which based on Jiles-Atherton hysteresis model and time-step electro-magnetic field FEA,is developed in this paper.The hysteresis loss obtained by this method is used as thermal sources in thermal finite element analysis.Result of thermal distributions can provide significant guidance for design of cooling system.%Terfenol-D是一种超磁致伸缩材料,它在变化的磁场作用下可以产生较其他磁性材料大得多的形变,可以作为改动材料应用于超声换能器中,但是这种材料的发热问题制约超磁致伸缩超声换能器功率的提升。超磁致伸缩超声换能器的热量主要来自Terfenol-D材料内部的涡流损耗和磁滞损耗,涡流损耗可以通过将材料切片的方式有效地减小,因此磁滞损耗就成了换能器的主要热源。本文提出一种考虑应力影响的基于反向Jiles-Atherton磁滞数学模型的新模型,并将它与时步法电磁场有限元分析法相结合,进行磁滞损耗的计算。将磁滞损耗作为热源进行温度场分析,得到超磁致伸缩超声换能器的温度分布,为超磁致伸缩换能器散热系统的设计提供了指导依据。