基于动力总成和车身整体的发动机怠速激励下车身振动仿真研究

Simulation research on vehicle body vibration by engine idle excitation based on integration of powertrain and vehicle body

综合运用多体动力学、有限元法、动态响应灵敏度分析和结构优化方法,研究基于动力总成和车身整体的发动机怠速激励下车身振动的动态仿真。以某国产客车为研究对象,分别建立十二自由度整车动力学模型和白车身有限元模型。以悬置系统的动载荷为桥梁,将动力学仿真和有限元仿真结合起来,定量求解发动机怠速激励下车身特征点的动态响应。对比分析特征点动态响应的仿真结果与实车测试结果,验证仿真方法的正确性。将此振动仿真方法应用到结构优化中,针对实车上出现怠速工况下VIP座椅位置振动异常问题,以动态响应灵敏度分析为指导,通过对车架和车身底板骨架整体结构局部调整和尺寸优化,提高了客车的乘坐舒适性能。

Based on integration of powertrain and the vehicle body, multi-body dynamics, finite element method, dynamic response sensitivity analysis and structure optimization were eomprehensively used to study dynamic simulation on vehicle body vibration that caused by engine idle excitation. Utilizing domestically manufactured passenger bus as object, a 12-DOF multi-dynamics mod- el and a finite element model for the Body-In-White （BIW） were established. In order to solve dynamic responses on feature points of BIW quantitatively, dynamics simulation and finite element simulation were linked through the dynamic loads, which were generated by engine idle excitation on powertrain mounting system. The comparison between results of simulation and test shows that this simulation method is accurate. This vibration simulation method was utilized in structure optimization to solve the problem of VIP seat vibration anomalies on idling condition. Under the guidance of the dynamic sensitivity analysis, riding comfort was greatly enhanced through partial adjustment and size optimization of the carframe-gestellboden structure.