Yasrebi N.

A fuzzy finite element (FFE) based method is used for modeling Magnetorheological(MR) Dampers with vague or imprecise uncertainties. As we know successful performance of MR devices or dampers require that they be tested under imprecisely defined conditions. However, physical prototyping and testing under vague conditions are expensive and time consuming. The limitations associated with physical prototype testing can be circumvented through numerical studies. FFE allows us to characterize possible variations of the behavior of a finite element model including imprecise data. Thereby, the design and the performance of the device in vague conditions and possible variation of MR damper response (damping force) can be checked. Since the accuracy of the finite element model is verified in experiment the FFE results are used in a fuzzy control system for active vibration suppression. Fuzzy sets can be used to represent the uncertainties in the MR fluid properties (like yield stress or magnetic properties), geometry (like fluid gap size), Electromagnetic properties (for example leakage through electromagnetic circuit) and physical properties of the MR damper (for instance in a mono-tube damper, the accumulator pressure). A sensitivity analysis procedure is used to streamline the number of input fuzzy variables. Then, vertex fuzzy analysis technique is used to compute the possibility distributions of the responses of the MR damper (damping force). This model is used in design of a smart suspension system for vibration control of a road vehicle. The finite element analysis of electromagnetic circuit and MR flow through damper piston is done by ANSYS. The FFE method used is found to be useful and suitable for use in the design of MR dampers and related control systems.