柴油机曲轴扭振多体动力学分析与研究

摘要

In order to analysis the torsional vibration changing law of the 4100QBZL diesel engine crankshaft ,a finite element model of crankshaft is built in ANSYS .A model analysis is carried out .On the basis of modal analysis ,the crankshaft of the flexi-ble body neutral file is built .The coupled multi-body dynamics model of crankshaft system is established ,the motions is cylinder pressure as experiment data under many conditions .After the simulation,the main journal,connecting rod journal load results is got.Then torsional vibration simulation is operated ,crankshaft torsional vibration amplitude with the load and speed is obtained . Results show that with the increase of engine speed and load ,the torsional vibration of crankshaft are tend to be larger ,and speed greater influence on torsional amplitude values ,the shafting vibration amplitude under various conditions satisfy engineering de -mand.The simulated results can be used to improve the NVH of diesel engine in optimum design .%为分析4100 QBZL型柴油机曲轴的扭转振动,建立该柴油机曲轴的有限元模型,对曲轴进行模态分析,并在模态分析的基础上获得曲轴的柔性体中性文件,建立曲轴系的刚柔耦合多体动力学模型,通过多组试验测量的缸内压力数据作为驱动力,进行耦合仿真,得到曲轴系各部件运动规律以及曲轴在柔性体模型下的主轴颈、连杆轴颈负荷仿真结果,并对曲轴进行扭振分析,获得发动机在稳定运转时曲轴扭转振动幅值随负荷和转速的关系.结果表明:随发动机转速以及负载的提高,曲轴的扭转振动均存在变大的趋势,且转速对扭振幅值影响更为显著.曲轴系的振动幅值在各工况下满足工程要求.研究结果对提高柴油机的噪声、振动、行驶平顺性(Noise、Vibration、Harshness,NVH)具有参考意义.