Modeling and application of MR dampers in semi-adaptive structures

The developing of technology has discovered new materials which have been applied to improve the performance of structures. The researchers have recently increased the attention in controllable fluids and its applications. Magnetorhelological (MR) dampers are devices that employ theological fluids to modify their mechanical properties. Their mechanical simplicity, high dynamic range, lower power requirements, large force capacity, robustness and safe manner operation in case of fail have made them attractive devices to semi-active control in civil, aerospace and automotive applications. The characteristics of the MR damper change when the theological fluid is exposed to a magnetic field changing its stiffness and damping coefficients. A non-linear new model based on the Bouc - Wen model, is employed to simulate the hysteresis behavior of the damper. The model considers the frequency, amplitude and current excitation as dependent variables. The finite element model (FEM) of the MR damper element has also been developed based on the proposed model. Subsequently finite element of the adaptive structure embedded with MR dampers has been established and the non-linear response of the whole structure is obtained. Experimental work was carried out to validate the simulations. For this study, a cantilever 3-D space truss structure with 4 bays exposed to different excitations has been considered in which one of the members has been substituted by the MR damper. A good agreement has been observed between the simulations and experimental data. (c) 2007 Elsevier Ltd. All rights reserved.