Optimal design for working clearance of rotary MRF dampers

In order to improve the performance of rotary MRF (MagnetoRheological Fluids) dampers, a calculation model of magneto-induced damping torque that is the controllable output of the dampers was introduced, the influences of the shape and size of the damper's working clearance on the magnetic field distribution and the output magneto-induced damping torque were analyzed according to the model. On the basis, a model for the optimal design of the working clearance was established. Taking the dampers with a constant clearance as benchmark and the maximum output magneto-induced damping torque as objective, iterative optimal design procedures were applied, under given condition, to the dampers with step- and wedge-shaped working clearances by means of the finite element analysis and structural optimization modules provided by ANSYS software. Experiments were also conducted. The experimental results conformed well with the optimal design results, which proved the validity of the models established for the torque calculation and clearance design optimization. Both the experimental and the optimal design results showed that the performance of the dampers with a step-shaped clearance is superior to the dampers with a constant clearance, and that the performance of the dampers with a wedge-shaped clearance is superior to the dampers with a step-shaped clearance.