Research On Thermal Coupling And Damping Effect Of Magnetorheological Damper With Inner Channel

With the rapid development in intelligent level of vehicle, the NVH(Noise, Vibration and Harshness) problems and the ride comfort of vehicle are gradually concerned by people. It is a great challenge to development and design of vehicle suspension. The magnetorheological damper(MRD) takes MR fluid as a working medium. It can provide a good electrical-mechanical coupling interface for intelligent structure system. However, the damping characteristic of MRD is deteriorated due to heat. Based on the damping requirement of Tiguan suspension, a novel MRD with the inner channel is designed in this paper. In order to provide a theoretical basis to the application of MRD, a research on the damping characteristic of damper is done in thermal equilibrium state. The detailed works of this paper are as follows:1. To promote the damping force and extend damping range, the structure of MRD is improved. According to the improved parameters of MRD, the mathematical model about the damping force is deduced, and the coil turns are calculated by analyzing the magnetic circuit.2. Based on the structure size of damper, the thermal mode of MRD is built in AMESIM platform. By utilizing white noise to simulate road irregularities, the thermal equilibrium temperature of fluid in MRD is analyzed under the condition of different vehicle speed.3. On the basis of the above work, the finite element model of fluid in MRD is established by ANSYS ICEM. The thermal coupling external characteristic of MRD is calculated by using mobile grid to simulate vibration in ANSYS CFX. The results show that the damping force of MRD has larger decline with the increase of car speed.4. Finally, the damping characteristic of MRD is tested on vibration test bed by simulating thermal equilibrium of damper. The test results are consistent with the simulation conclusions. Compared with test curves that ignore temperature under the condition of same electric current, the results show that the damping force of MRD considering temperature is obviously dropped. Therefore,the influence of thermal temperature should be considered when the MRD is applied in engineering practice. Besides,the experimental results indicate that the vibration of the test bed affect the plumpness of damping force-displacement curve, so the stiffness of the test bed should be appropriately improved.