Study On Speed-up Coach's Car Body Vibration

The multi-rigid mechanical system is the basal theory of vehicle dynamics, it's main subject is bogie, spring suspension system and wheel-rail relationship. So it could not analyse the elastic vibration of elastic system. This theory could fit the vehicle design when the speed is low. But during the management of the high speed in recent years, the studies of vibration of vehicle become more and more important. The vibration could cause large harm, mostly include the vehicle steel structure fatigue damage before it's time, shorten rubber, spring's life and affect the security. The noise affect amenity of ride, vitiate the instrument and make it does error and so on. In this way, we know the vehicle system dynamics has some limitation in vehicle analyses and need some good methods to make up. Now we could solve the problem by build elastic vehicle model.Use the software I-DEAS build the model of vehicle and inner decorations, then dynamics analyzes elicit its free frequency and modal. The vehicle finite element model is not only satisfied the response analyses of entire car, but meets the analyses of the part of vehicle and inner decorations, and then it is response analysis for vehicle. As to load model, it contains unbalance dynamic load, wheel flaw, abrasive load and rail gap exciting load. At the same time, all of those loads relate to the velocity of the car, so it could also analysis the response from the different speed: 100km/h, 120km/h, 140km/h and 160km/h.We could judge if it is resonant by the way of analyzing the car body, side wall, wagon top and inner decorations under reasonable cyclic exciting load. Sequentially, we can improve the construction of vehicle and inner decorations and ameliorate the amenity and prolong fatigue lifetime, then give a reasonable betterment project.