Analysis And Optimization Of NVH Performance Of Air Condition Compressor’s Bracket In A Certain Vehicle

As an indispensable subassembly of power assembly, air conditioning compressor is similar to the kernel of automotive air conditioning system, its main function is to provide power by the engine and plays a role in compressing and conveying refrigerant steam. The air conditioning compressor generally is connected with engine cylinder by the bracket,so the problem about noise and vibration is valued increasingly,the noise of air conditioner system mostly caused by the compressor system’s excitation source, its performance directly affects vehicle’s comfort and control stability, meanwhile affecting car ’s NVH performance and vehicle performance particularly obviously.This paper aims at the noise problem of air condition compressor’s bracket under the idle circumstance, studying the bracket’s dynamic characteristics by the method of simulation analysis and experiment test. Firstly it conducted subjected assessment under the idle condition, lots of experimental tests were carried out by Belgian LMS company ’s Test. Lab for the above noise problem, by dint of frequency spectrum and modal frequency response analysis, the cause of noise related failure frequency was located; Then it established finite element model of air condition compressor’s bracket, at the same time the modal frequency response simulation analysis with MSC.Nastran was conducted, by contrast results of the experimental test with simulation,which validated the correctness of FEA model, at this moment, by dint of calculating the static stiffness and strength of simulation to observe the bracket’s stiffness and strength performance under bending condition.With the purpose of solving the above problem, it proposed a solution by improving the bracket’s structure to improve the compressor’s static and dynamic performance,meanwhile verified the solution’s correctness and feasibility by adopting the same method; based on modified structure of bracket, taking advantage of optimizing means by Optistruct, choosing bracket’s first-order natural frequency and static bending stiffness as the optimization objective, it had the aid of weighted compliance as objective function and constraint its mass fraction, therefore in order to make multiple objective analysis of compressor bracket’s topology optimization,above work should be spread.End on this basis, static or dynamic analysis of compressor bracket was carried out,thus getting first 2 rank inherent frequency, mode of vibration, static stress and strain parameters under its some special cases like bending circumstance, then contrast it with original air compressor bracket’s performance analysis’ s result, results showed that on condition satisfying the lightweight, dynamic performance of bracket had improved distinctly, meanwhile vehicle’s whole NVH performance improved obviously, thus its rigidity and strength were guaranteed.