Multi-objective Optimization Design And Practice On Structural Parameters Of Magneto-rheological Fluid Damper

Magneto-rheological(MR) fluid damper is controllable, simple in structure, quick in response, low energy consumption, large dynamic range and easy to control. Its adjustable damping force and electromagnetic response time of the coil in the piston top are two important performance indexes for the damper.The breadth of the damper is inversely proportional to adjustable damping force and electromagnetic response time through analyzing and by setting adjustable damping force and electromagnetic response time as objective functions and the length and breadth of the damper channel as optimal variables. Thus, the relatively great force and the relatively short response time can not be optimal at the same time. By using MOGA(Multi-objective Genetic Algorithm), this article conducted optimal electromagnetic response time as objective functions, this article conducted optimal design on MR fluid damper and manufactured the physical sample of it according to the optimized structure parameter in order to verify the rationality of the optimized proposal by experimenting. The specific procedure is as follows:①MR fluid and MR fluid damper and their application in automotive suspension are briefly described. Several representative types of macroscopic and microcosmic model of MR fluid are introduced and the research status of MR fluid damper in structure and electromagnetic parameter optimization is concluded. The research significance and content of this article are put forward then.②Starting from the micro structure of MR fluid, the magnetisable particles in MR fluid can be considered as identical dipoles. Through the chaining mechanism of the MR fluid in the magnetic field, it was assumed that there is no interaction between the dipole chains. The shear force of a single chain generated by the relative movement of the two slabs is analyzed. It was also assumed that if the included angle between the chain and the magnetic field meets the shear yield stress of the MR fluid obtained according to normal distribution, the model can be simplified as a bi-viscidity one.③ The working pattern of the MR fluid damper designed in this article was described. The MR fluid in the damp channels of the MR fluid damper was analyzed according to rheology and the damping force of the MR fluid damper was calculated with a biviscous model. Also, the parameter of the magnetic circuit was ensured according to the basic designing standard of the magnetic circuit. The response time ofthe electromagnetic loop can thus be calculated.④ Aiming at the adjustable damping force and the response time, the multi-objective optimization process of the MR fluid damper was introduced. The type solution obtained from the mixing method and the optimized result obtained from the weight coefficient method were compared, the parameter which suits engineering application better were chose to be processed to verify the rationality of optimization.⑤The indicator diagram under different field currents was obtained by testing the indicating character of the MR fluid damper. By adding series resistance, the electromagnetic response time was measured. Compared with the theoretical calculating value of the damping force and electromagnetic, the experimental value of the damping force slightly deviated. And the reason of deviation was analyzed.At last, all the procedures from this article was concluded, also, the deficiencies during researching and the further research direction was pointed out.