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Showing 3 results for Magneto-Rheological
Reza Tikani, Saeed Ziaei-Rad, Mohsen Esfahanian,
Volume 14, Issue 10 (1-2015)
Abstract
Hydraulic engine mounts are applied to the automotive applications to isolate the frame from the high frequency noise and vibration produced by the engine. It also designs to reduce the engine shake motions from the road distribution usually occurred at low frequencies. This implies that the stiffness and damping properties of the engine mount should be amplitude- and frequency- dependent. In the semi-active engine mounts this task will be done by changing the mount parameters such as stiffness and damping. Magneto-rheological fluids are used in the mounts to change their damping by applying the magnetic field. When the current is applied to the electromagnet and the magnetic field is present, the behavior of the magneto-rheological mount is changed by the magneto-rheological effects. In this paper, a prototype magneto-rheological mount was built and experimentally evaluated. Also, the mathematical model of the mount was developed to represent the dynamic behavior of the engine mount system. The model was numerically solved based on the prototype parameters and simulated in MATLAB. The experimental results were used to verify the model in predicting the mount characteristics.
Keramat Malekzadeh Fard, Mohsen Rezaei Hassanabadi, Mostafa Livani,
Volume 14, Issue 15 (3-2015)
Abstract
In this study, single-objective and multi-objective optimization of curved sandwich panel with composite face sheets and magneto-rheological core have been done to maximize the first modal loss factor and minimize the mass by using genetic algorithm. The studied sandwich panel was curved with simply support boundary condition. In order to derive the governing equations of motion, an improved high order sandwich panel theory and Hamilton's principle were used for the first time. The face sheet thickness, core thickness, fiber angles and intensity of the magnetic field have been considered as optimization variables. In single-objective optimization, the optimized values of variables were calculated. The results showed that the structures tend to have thick core and thin face sheets which seems physically true. As the magneto-rheological fluid placed in the core, it has a significant effect on the increasing of the modal loss factor. For the multi-objective optimization the Pareto front of optimal technique was presented. Then for the first time at this field, the set of optimal points are selected based on TOPSIS method and it was showed that in the case of similar size and mass, modal loss factor of double-curved panel is more than sigle-curved.
M. Ghafarian Eidgahi Moghadam, M.m. Shahmardan , M. Norouzi,
Volume 19, Issue 4 (4-2019)
Abstract
Magneto-rheological damper is one of the most widely used mechanical equipment, which absorbs mechanical shocks by use of magnetic fluid and electrical coil in its structure. In this paper, for the first time, dissipative particle dynamics as a mesoscopic scale modeling method was used to simulate a magneto-rheological damper and its magnetic fluid. Data from 3 categories including magnetic fluids with brand names 122-EG, 132-DJ, and 140-CG have been used and effect of their physical properties on power of damping force have been investigated. Results of modeling show that by increasing shear rate of fluid, shear stress is first increased and, then, it is applied to a constant value, which results in a greater shear stress by applying a stronger magnetic field. It is also observed that, with increasing both maximum piston velocity and strength of magnetic field, maximum power of damping force increased, which in 140-CG is higher than the other fluids. Results of sensitivity analysis show that weight of magnetic particles and strength of dissipative forces have the greatest effect on damping force, in such a way that by increasing weight of magnetic particles and decreasing the dissipative force of particles, accumulation of magnetic particles decrease, so, increasing quality of damping. It was also found that 122-EG is more suitable than other types of magnetic fluids in forming standard magnetic particle chains, and provides a more favorable viscosity distribution for damping.
