RESEARCH ON THE MAGNETO-MECHANICAL EFFECT IN ACTIVE AND PASSIVE MAGNETOSTRICTIVE VIBRATION ISOLATOR

The actuation system, which is composed of magnetostrictive actuator and compliant displacement amplifier, has the advantages of high precision and large actuation force. It is connected in parallel with passive vibration isolator. The resulting active and passive vibration isolator can make up for the deficiencies of passive isolator on low-frequency and micro-amplitude conditions. In this paper, a nonlinear magnetostrictive actuation model is proposed based on Jiles-Atherton model. Magneto-mechanical effect is comprehensively characterized by being decomposed into stress related effects on effective field, magnetization, magnetostriction and Young's modulus. A dynamic model of the isolator is established considering the coupling effects between active isolator and passive isolator. With the coupling effect, the performance of actuation system is related to passive isolator parameters. With higher passive isolator stiffness, the actuation displacement decreases and the required actuation force increases. The coupling effect also leads to the change of equivalent stiffness of the isolator due to the ?E effect of magnetostrictive material. The influence of coupling effects can be weakened by parameter design of compliant amplifier. The performances of the active and passive vibration isolator are validated by numerical simulation. Three kinds of vibration frequencies are used, which are below, around and beyond natural frequency of the isolator, respectively. Compared to passive vibration isolator, better vibration isolation performances are acquired by adding active vibration isolator on all three conditions. And the calculation results show that the proposed model considering magneto-mechanical effect can reach a higher accuracy.