Structural Design And Analysis Of A Pneumatic-electromagnetic Active-passive Hybrid Vibration Isolator

The application of floating raft vibration isolation improves ability of the submarine's acoustic stealth effectively, while higher requirements for the bearing capacity and the low frequency vibration isolation performance of the vibration isolators are presented. These requirements can be well met through the integration of a pneumatic spring with great bearing capacity and an electromagnetic vibration isolator with good low frequency vibration isolation performance. It has very important practical value to research in a Pneumatic-Electromagnetic Active-Passive Hybrid Vibration Isolator(PEAPHVI), which is composed by a pneumatic spring and an electromagnetic vibration isolator.In this paper, the stiffness of a pneumatic spring and the electromagnetic vibration isolator is studied. A PEAPHVI is designed and the design criterion of the isolator is given. The main research works of the paper are showing as follows:(1)The stiffness characteristics of the maglev isolator were studied. The expression of electromagnetic force was deduced with magnetic circuit method. The expression shows that the electromagnetic vibration isolator has negative stiffness which is proportional to the square of bias current. The magnetic field of the electromagnetic vibration isolator was simulated with Workbench. The simulation results show that the stiffness of the electromagnetic vibration isolator is obviously nonlinear.(2)A novel pneumatic spring was studied and designed. The expressions of the bearing capacity, stiffness and natural frequency of the pneumatic spring were derived by the analytical method. The stiffness and natural frequency of the pneumatic spring were analyzed by ANSYS15.0 software. The results show that the stiffness of the pneumatic spring is almost constant when it is stretched, and the stiffness is nonlinear when it is compressed. The designed pneumatic spring keeps a low natural frequency.(3)This paper proposed a new PEAPHVI. The characteristics of the bearing capacity and the ability to suppress low frequency resonance were considered comprehensively. There is a relationship between the stiffness of the pneumatic spring and the one of the electromagnetic vibration isolator.(4)This paper provided a design criterion of the PEAPHVI. According to the design criterion, an example was designed. The natural frequency and force transfer rate of the PEAPHVI system were simulated when the stiffness of the air spring and the magnetic suspension isolator were different. The results show that the better vibration isolation performance can be achieved by increasing the absolute value of the electromagnetic vibration isolator's stiffness or decreasing the stiffness value of the pneumatic spring.