某型柴油机曲轴系的扭振性能分析

Torsional Vibration Analysis of Crankshaft System for Diesel Engine

扭振是曲轴最为主要的振动形式之一,对曲轴的危害也最为严重。扭振过程中曲轴运转不均匀,伴有机械敲击和抖动等现象,长期运行会发生曲轴断裂、减振器爆裂等故障。我们采用多体动力学AVL-EXCITE Designer软件建立某型柴油机曲轴系统模型,通过CREO、有限元软件、AVL-Boost软件计算某型柴油机曲轴系统转动惯量、结构尺寸、质量、扭转刚度、缸压曲线等参数作为某型柴油机曲轴系统模型的输入,分析某型柴油机正常工况下和某缸停火下的自由振动和强迫振动情况,得到了扭振系统图、临界转速图、扭转系统模态、固有频率、最大总扭矩,确定出柴油机的临界转速、振型、振幅、扭转角位移、扭振应力,为柴油机运转过程中的扭振状况提供重要的理论支撑。

The torsional vibration is one of the main vibration forms for the crankshaft and the damage to the crankshaft is also the most serious. In the process of torsion vibration, the crankshaft is not running evenly with mechanical percussion and jitter. It will break the crankshaft and shock the absorber in the long run. The paper using the multi-body dynamics software AVL-EXCITE Designer establishes the crankshaft model. The model obtains the torsion vibration characteristics (eg, moment of inertia , the size of structure, mass, torsional rigidity, the curve of cylinder pressure ) of diesel engine from the software of CREO、AVL-Boost and finite element software. The simulation model can analyze the free and forced vibration under normal or abnormal condition to obtain the diagram of torsional system and critical speed, the mode of torsional system, the inherent frequency, the maximum total torque. In the end, we can get the critical speed, mode of vibration, amplitude, the torsion angular displacement, the torsional vibration stress. It provides important theoretical support for the torsional vibration of diesel engine.