A new design of magnetic circuits in magnetorheological dampers for simple structure subjected to small stroke and low damping force

Abstract

A magnetorheological (MR) damper is popularly applied for vibration control owing to its fast response and the easy controllability of the field-dependent damping force. However, most of the existing MR dampers developed so far possess design complexity and a high manufacturing cost due to complicated coil structures. To resolve these drawbacks of the existing MR dampers, a novel magnetic circuit positioned separately from the piston head of MR damper with a simple structure is proposed in this work. As a first step, a design configuration using the operating principle of the magnetic circuit is demonstrated, and subsequently, the magnetic analysis of MR damper is carried out through an analytical approach and the finite element method. In the magnetic analysis, the magnetic flux density is numerically calculated at various piston locations with different applied currents. After determining the principal design parameters of the proposed MR damper, experimental validation to demonstrate the concept of the new magnetic circuit is performed. The effect of the piston stroke length on the damping force is evaluated as a function of the current. In addition, it is discussed that the proposed MR damper can provide much higher control range of the damping force than conventional types of MR dampers in a low level of damping force.