| With the rapid development of the domestic economy,the ownership of private carhas increased dramatically.Now,drivers not only pursue for the car ’s power, safety,handling and individual exterior, but also pay more and more attention to NVH（Noise、Vibration、Harshness）characteristics,which need a good powertrain mountsfor cutting off the vibration from the engine and ground.This dissertation establish a automotive powertrain and MRF hydraulic mountvibration isolation system and analysis its vibration by the way of SIMULINKco-simulation， which based on the existing research result and come from acollaborative enterprise project with a company about development of a MRF hydraulicmount,which means that the structural design of single mount is placed in a largersystem—automotive engine powertrain vibration isolation system.Specifically, inthe early time of a part we take into account its performance in entire system and all forthe best performance of system, which is the system design ideas, but also theacademic significance of this dissertation.Under the guidance of this idea,the researchcontents of this dissertation are summarized as follows:Firstly,the mechanics models and dynamic characteristics of MRF hydraulic mountare introduced.MATLAB Function program is written on the basis of the models andcharacteristics to simulate the dynamic characteristics of MRF hydraulicmount,Meanwhile, the dynamic characteristics test of MRF mount is made in the MTStest stand for obtaining curves of dynamic stiffness and damping lag angle.Then,thefeasibility and correctness that MATLAB Function program is used to simulate thedynamic characteristics of MRF hydraulic mount in0~100Hz are proved by comparisonof the measured and simulated.Secondly, the powertrain with MRF hydraulic mount vibration isolation system inlow frequency(0~100Hz) is established.The way that generalized force(General Force)and sleeve force(Bushing) are combined to simulate the nonlinear characteristics ofMRF hydraulic mount and rubber mount is used to solve the problem that the sleeveforce(Bushing) can not use some variable parameters to set the stiffness and damping.In order to remedy deficiencies of MATLAB parameters program in the simulationof the dynamic characteristics of MRF hydraulic mount in high frequency(100~200Hz),this paper introduced the fluid-solid coupling finite element analysis technology to simulate the dynamic characteristic of MRF hydraulic mount in high frequency, andcompared the test data of MTS bench for proving the correctness of the finite elementanalysis, and put forward the preliminary conception of the establishment ofco-simulation model of automotive powertrain and MRF hydraulic mount in highfrequency excitation,which is treated as references for the follow-up researchers.Finally, because in the most time automotive engine generate0~100Hz incentive,this paper researches the vibration isolation performance of powertrain mount underdifferent working conditions(including low speed, idling,medium speed, high speed andcontinuous)on basis of automotive engine and MRF hydraulic mount co-simulationmodel. The influence of structural parameters of MRF hydraulic mount on powertrainvibration situation is analyzed and related laws are summarized, which are regard as thebasis to optimize the vibration isolation performance of MRF hydraulic mount at idling.To sum up, this paper relates to the "three kinds of comparison, two innovations,two optimization"."Three kinds of contrast", namely the comparison of MRF hydraulic mount andordinary rubber mount vibration isolation performance;the comparison of the results ofMRF hydraulic mount dynamic characteristics by parameters simulation and by MTSbench test; the comparison of the result of hydraulic mount dynamic characteristics byfinite element and by MTS bench test."Two innovation", namely the first application that MRF hydraulic mountnonlinear dynamic characteristics is simulated by overlying general force and sleeveforces; the fluid-solid coupling finite element technique are firstly applied to automotiveand MRF hydraulic mount co-simulation system by the command stream and batchprocessing，which expands research method of MRF hydraulic mount, enrich thepractical application of finite element analysis and multi-body dynamics."Two optimization", namely the vibration isolation performance of MRF hydraulicmount at engine idling is optimized;Original low frequency co-simulation system isfurther optimized by fluid-solid coupling finite analysis... |
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