This paper presents an optimal design of a magnetorheological (MR) brake for a middle-sized passenger car which can replace a conventional hydraulic disc-type brake. In the optimization, the required braking torque, the temperature due to zero-field friction of MR fluid, the mass of the brake system and all significant geometric dimensions are considered. After describing the configuration, the braking torque of the proposed MR brake is derived on the basis of the field-dependent Bingham and Herschel-Bulkley rheological model of the MR fluid. The optimal design of the MR brake is then analyzed taking into account available space, mass, braking torque and steady heat generated by zero-field friction torque of the MR brake. The optimization procedure based on the finite element analysis integrated with an optimization tool is proposed to obtain optimal geometric dimensions of the MR brake. Based on the proposed procedure, optimal solutions of single and multiple disc-type MR brakes featuring different types of MR fluid are achieved. From the results, the most effective MR brake for the middle-sized passenger car is identified and some discussions on the performance improvement of the optimized MR brake are described.

This paper presents the geometric optimal design of magnetorheological (MR) valves in order to improve valve performance, such as pressure drop. The optimization problem is to find the optimal geometric dimensions of MR valves constrained in a specific volume. After describing the configuration of MR valves, their pressure drops are investigated on the basis of the Bingham model of an MR fluid. Then, the valve ratio, which is an objective function, is derived by considering the field-dependent (controllable) and viscous (uncontrollable) pressure drops of the MR valves. Subsequently, the optimization procedure using a golden-section algorithm and a local quadratic fitting technique is constructed via a commercial finite element method (FEM) parametric design language. From the constructed optimization tool, optimal solutions of the MR valves, which are constrained in a specific cylindrical volume defined by its radius and height, are calculated and compared with analytical ones. In addition, several different types of MR valves are optimized in the same specific volume and results are presented.

This study presents an optimal design for magnetorheological (MR) valves for minimizing the control energy to be applied to coils to control the pressure drop of the valves. The optimization problem identifies parameters such as applied current, coil wire size and geometric dimensions of the valves which satisfy the specified pressure drop and inductive time constant requirements. After describing the configuration of MR valves, their pressure drops are obtained on the basis of the Bingham model of MR fluid. Then, the control energy which is an objective function and the inductive time constant are derived. Subsequently, an optimization procedure using a golden-section algorithm and a local quadratic fitting technique is constructed via a commercial finite element method parametric design language. Using the optimization tool developed in this study, optimal MR valve configurations are identified, which are constrained to a specific cylindrical volume defined by its radius and height. In addition, optimization results for MR valves with different required pressure drops and different constrained volumes are obtained and presented.

This paper presents an optimal design of a passenger vehicle magnetorheological (MR) damper based on finite element analysis. The MR damper is constrained in a specific volume and the optimization problem identifies the geometric dimensions of the damper that minimize an objective function. The objective function consists of the damping force, the dynamic range, and the inductive time constant of the damper. After describing the configuration of the MR damper, the damping force and dynamic range are obtained on the basis of the Bingham model of an MR fluid. Then, the control energy (power consumption of the damper coil) and the inductive time constant are derived. The objective function for the optimization problem is determined based on the solution of the magnetic circuit of the initial damper. Subsequently, the optimization procedure, using a golden-section algorithm and a local quadratic fitting technique, is constructed via commercial finite element method parametric design language. Using the developed optimization tool, optimal solutions of the MR damper, which are constrained in a specific cylindrical volume defined by its radius and height, are determined and a comparative work on damping force and inductive time constant between the initial and optimal design is undertaken.

This paper presents an optimal design of a magnetorheological (MR) shock absorber based on finite element analysis. The MR shock absorber is constrained in a specific volume and the optimization problem identifies geometric dimensions of the shock absorber that minimize a multi-objective function. The objective function is proposed by considering the damping force, dynamic range and the inductive time constant of the shock absorber. After describing the configuration of the MR shock absorber, a quasi-static modeling of the shock absorber is performed based on the Bingham model of an MR fluid. The initial geometric dimensions of the shock absorber are then determined based on the assumption of constant magnetic flux density throughout the magnetic circuit. The objective function of the optimization problem is derived based on the solution of the initial shock absorber. An optimization procedure using a golden-section algorithm and a local quadratic fitting technique is constructed via a commercial finite element method parametric design language. Using the developed optimization tool, optimal solutions of the MR shock absorber, which is constrained in a specific cylindrical volume defined by its radius and height, are determined. Subsequently, a quarter-car suspension model with the optimized MR shock absorber is formulated and the vibration control performance of the suspension is evaluated under bump and sinusoidal road conditions.