Flexible Multi-body Simulation Of Brake System Based On Virtual Prototype

With the development of the economic, the vehicles have been one of the best means of transportation in modern time. Because the brakes play an important part in the vehicles' Safety and Comfort, how to reduce the cars' brake vibration and noise has become an important research topic.First the paper introduced the history of brakes, the research status of brake vibration and noise, then introduced a multi-body dynamic model of the basic theory and self-excited vibration theoretical of the disc brake vibration, All these theories provide a feasible means for further develop. Next, introduced how to build the flexible multi-body of the brake system using the FEA technology and the multi-body dynamic technology. Including how to get the model neutral file(MNF)of the brake disc and brake pad by utilizing the FEA technology. In the process of building the MNF, the free model analysis of the brake disc and pads were studied. Introduced the process of the multi-body dynamics modeling:import flexible bodies and rigide bodies, in order to reduce the computing time, the macro command was applied to add dummy parts on flexible body. In order to calculate accurately, should gave the rigid bodyies a certain material properties, add the constraints between the various components, etc. At last veryfy the model. The pressure and friction between the disc and brake pads were achieved by the macro command.The brake angular velocity and acceleration curves can be carried out by dynamical simulation and analysis. From these curves we can get that the friction increases along with the friction coefficient, but the more likely to brake vibration and noise occurs, the vibration and noise can worsen the stability of the brake system. In contrary, if we lower the friction coefficient, the braking efficiency will also lower. So When selecting brake pads, the friction coefficient must fulfill the request of both brake efficiency and stability. The brake vibration and noise would also happen when installation errors occurred in the automotive brake, the installation errors means brake disc rotation axis and the disc axis don't coincide.The flexible multi-body model not only concerned the flexibility deformation of the components of the brake system, but also concerned the influence of moment of inertia of the rotating components of the automobile, so the simulation was more reasonable. The method of building the flexible multi-body model is universal and it can be useful for future disk brake noise analysis and structural optimization design.