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In order to study the brake squeal issue of an SUV disc brake, a complete finite element model (FEM) for contact coupling of disc brake is established by using finite element software. The validity of the FEM is verified by the experimental modal analysis method. The complex eigenvalue analysis method is adopted to predict the instable mode of the system. The influence of friction coefficient, brake rotation speed, brake pressure and disc stiffness on brake squeal is further analyzed.

The ride comfort of heavy trucks is related to many factors, which include vehicle operating scenarios and vehicle structure parameters. An investigation of the influence of different factors on the ride comfort of heavy trucks was conducted. Based on the elastic theory of a uniform Euler-Bernoulli beam with both ends free, a 6 degree of freedom (DOF) half rigid-elastic vibration model of the vertical dynamic response was developed. The rigid-elastic model is more suitable to describe the actual movement of heavy trucks. The DOFs include vertical displacements of the body and each of two axles, the pitch displacement of the body, and the first and second order bending displacements of the body. The root mean square (RMS) values of body accelerations, dynamic deflections and relative dynamic loads form the evaluation index. Based on the rigid-elastic model, the influence of different factors on the ride comfort of heavy trucks is analyzed in the frequency domain.

The hanger location layout is crucial, because it is related to the rubber hanger life, the natural frequency of the exhaust system and the force transferred to the body from the exhaust system. In order to solve the hanger layout problem of a new developed automotive exhaust system, the finite element method (FEM) of the automotive exhaust system including the powertrain was established. The correctness of the FEM model was verified by means of experimental modal analysis. Using average driving DOF displacement (ADDOFD) method, the hanger Location was arranged. The static and vibration analysis of the exhaust system was carried out to verify the hanger location layout. The weight analysis results indicate that the maximum displacement of the rubber hanger satisfies the design requirements. The static analysis results under 4g acceleration indicate the maximum stress meets the strength requirements of the material.

In order to study the influence of body flexibility on the truck ride comfort, a 4 DOF half vibration model of truck based on the motion synthesis between rigid body and body flexibility is established using elastic beam theory of equal section with both free ends. At the same time, a corresponding 2 DOF rigid vibration model is also built. The frequency response functions of system and response variables of two models are derived based on front wheel. The power spectral densities and the root mean square values of body acceleration, dynamic deflections and relative dynamic loads are obtained. By comparing the simulation results of rigid-elastic model and rigid model, it shows that body flexibility has a great impact on truck ride comfort and it cannot be ignored.