Mechanical performance of a novel magnetorheological fluid damper based on squeeze-valve bi-mode of MRF

In this paper, a novel magnetorheological (MR) damper working in the squeeze-valve bi-mode of MR fluid (MRF) was developed. The damper was consisted of two parts: the valve part and the squeeze part. Both of the two working parts could provide damping force when the damper worked. Firstly, the model of the novel damper was established to ensure that the damper structure was suitable for our design. Then, the magnetic field distribution inside the MR damper was simulated. The simulated results showed that the magnetic flux density was 120 mT when the current in the coil was 2.0 A, and the magnetic field distribution was uniform at the working area of the MRF. The magnetic flux density inside the damper could be controlled by changing the current in the coil. Finally, the damper was fabricated and its mechanical properties were tested by the universal testing machine (MTS 809). The influences of the displacement, frequency, current, and velocity on the damping force were systematically analyzed. The test results indicated that the largest damping force provided by the MR damper was about 6.5 kN. The curves of the damping force versus displacement were plump, which indicated that the ability of the damper to expend energy was well. The effective damping increased from 31.5 to 620 kNs m(-1) when the current increased from 0 to 2 A. The results indicated the properties of the damper could change in a huge range. To analyze the semi-active control performance of the damper, the back propagation neural network was trained to predict the damping force. The predicted results matched well with the experimental results, which indicated that this novel MR damper had great potential in the semi-active control field.