Design Of Magnetorheological Elastomer Vibration Absorber For IMU And Its Performance Analysis

The accuracy of inertial measurement unit (IMU) in the missile is affected by overloads, shocks and vibrations which are caused during flight process. In order to achieve high-precision applications of IMU, the design of the vibration reduction system for IMU is required. However, one can’t thoroughly solve the multimodal resonance response problem caused by broadband random vibration by only using conventional vibration absorber. Therefore, a novel vibration absorber which can change the stiffness and damping of the vibration system in real-time is to be developed. As a new type of smart material, the magnetorheological elastomers (MREs) have good properties such that its stiffness and damping are controllable, which makes the MREs having good prospects in the application of IMU vibration reduction.In this paper, a pure compression MRE vibration absorber whose stiffness is adjustable is designed for a particular IMU, and test for the performance of the vibration absorber is implemented. Detailed work is as follows:(1) The dynamics equation of IMU vibration system is established by using the transfer matrix method for multibody systems (MSTMM), and finally the stiffness of the vibration absorber and the natural frequency of the system are determined by solving the dynamics equation.(2) A preparation method for MREs is designed, and a magnetic field generating device to prepare MREs is designed. The simulation of the magnetic circuit inside the preparation cavity of the magnetic field generating device using the ANSYS Workbench software is carried out, the result shows that the magnitude of the interior magnetic field has reached 1.106T. The mechanical properties of the MREs prepared by different base materials are analyzed.(3) Using a new preparation process, the MREs, whose iron particle content are 30%, 40%,50% and 60%, respectively, have been prepared. Further, the static mechanical experiment for MREs with different proportion of iron particle is done. The results show that the maximum MR effect is found in the MRE which contained 60% iron particle.(4) The overall structure of vibration absorber is designed according to the stiffness required, the magnetic circuit of the vibration absorber is calculated, the vibration absorber’s magnetic circuit is simulated using ANSYS Workbench module, the overall program of processing the vibration absorber is designed, and the performance test for the vibration absorber is carried out, the result shows that its stiffness has changed 40.55%.