Research On Reducing Disk Brake Squeal Noise Using Finite Element Methods

Based on the theory of Finite Element Method and Vibration Mechanics,asquealing disk brake model is established in the Finite Element software,ANSYS.The closed-loop coupling model includes disk,clamp,bracket,out andin pad.Based on the system model, calculation and analysis are performed to findwhich structure factors affect squeal phenomenon greatly. Finally every factor wasdiscussed.The whole article includes six chapters:In chapter one,we described the harm that brake squeal noise brings to peopleand the pressure to be solved.We also reviewed on the growing history,status quoand future trend of brake squeal noise research.The FE model are coming throughfrom simple to complication,from few parts to complicated assembly.Finally wedescribed the research content and significance briefly.In chapter two,we introduced the work principle of brake,and analysis themechanism of arousing brake squeal. We discussed the relations between vibrationand noise.listed some familiar factors caused brake noise and the correspondingmeasures of eliminating it.Finally we introduced some research methods.In chapter three we introduced the basic theories of finite element method,andlisted the method-Component Mode Synthesis we will use in this article.It is onekind of reducing DOF(Degree of Freedom)method.Applying it we can divide amodel into several parts,then calculate them separately,at last process the ModeSynthesis.Due to adopting the low frequency mode of components,the assemblymodel's DOF reduces greatly,and we can calculate the model in several computersto saving time.We mainly introduced the process of establishing model in chapter four.Firstwe briefly described the function of ANSYS,then we established the model usingthe ANSYS's preprocess module.The model includes disk,clamp,bracket,outand in pad.In order to saving calculate time we should simple the model in the caseof ensuring precision.The most important step is to simple the friction contactsurfaces and elasticity contact surfaces,so that we can group the closed-loopcoupling model.In chapter five we calculate the established model length by length,includingcomponents mode analysis,mode parameter extract and the analysis of the coupledmodel.Then we get the results,from the results we can find that the closed-loopcoupling model reflect the brake noise very well.Add friction coupling into thebrake system caused the stiffness matrix asymmetry,so the system becomesunstable,the squeal noise appears.Along with the friction coefficient increasing,the system unstable tendency and squeal tendency increased.By changing thecontact stiffness simplex affects system trivially , can not eliminate brakesqueal.The squeal tendency mode(unstable mode)is composed of severaluncoupled component mode,not a certain mode.Analyzing the unstable mode wefound the key component modes,which affect the whole system most greatly.The sixth chapter is the summary.Described the main work and theconclusion we obtains,as well as the future research direction.This articlesuccessfully simulated the brake noise phenomenon application finite elementmethod,has obtained a quite satisfying result and discovered the question root.Butthere is still a long way to go to solve squeal noise,such as we needed confirmationby experiments.In addition the simplified model could bring certain errors,so laterresearch work still have to continue to simulate the actual operating mode better,then the question could be solved better.In brief, it is one extremely effective method application finite elementmethod to analyze the brake noise.The finite element analysis software hasprovided big convenient for the brake design work, reduced the product productioncycle. Along with the computer technology development, the finite element methodcertainly can play the major role in the automobile product development.