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.

A review on design and modelling methods of magnetic circuit cores for MR elastomers and MR fluids based system

“…However, the efficiency might be decreased with the insulation layers because of the less energy of the magnetic field. A new distribution of magnetic coils was presented in [57]. This design proposed a new position of the coil belonging to the upper chamber or/and the lower chamber.…”

Design and experimental research of stepped bypass magnetorheological damper

“…In order to solve the disadvantages of complex coil structure and high manufacturing cost of most magnetorheological dampers, magnetorheological dampers with simple structure and new magnetic circuit with separate positioning of the piston head were designed. It was derived that a much higher range of controllable damping force than the conventional one can be provided at low damping force level (Lee et al, 2021). Based on the idea of using a large gap at high speed and a small gap at low speed, a new MR damper based on axial variable damping gap (MRD-VDG) was proposed, and a prototype damper was designed and fabricated to verify the effectiveness of the damper design (Xi et al, 2021).…”

Theoretical switch model of novel asymmetric magnetorheological damper for shock and vibration application

“…It has been proved that the innerto-outer flow channel ratio is greater than 0.65, and the error in using the plate approximation to convert the annular flow channel to a plate model for analysis is less than 1% [21,22]. In addition, combined with different flow modes (shear mode [23,24], flow mode [25], extrusion mode [26,27], and mixed mode [28,29]) and various channel shapes (multi-coil [30][31][32], spiral channel [33,34], curved channel [35,36], multi-parallel channel [37,38], tapered hole-shaped channel [18], bypass channel [39,40]) the flat-plate approximation still can characterize mechanical models well. However, given the conical channel shape of the CFC-MRD structure, the conventional parallel plate model cannot fully capture its flow characteristics.…”