某柴油机曲轴扭振合成应力控制计算分析

Analysis on the Composite Stress Control for Torsional Vibration of a Diesel Engine Crankshaft

针对某新型柴油机轴系扭振计算中曲轴扭振附加应力过大问题,对激励进行分析并开展扭转振动计算;尝试采取不同途径消减过大扭振合成应力。得到如下结论:当今柴油机强化指标不断提高,而CCS推荐的气体激励简谐分量幅值相对偏小,从安全角度出发,扭转振动计算时应按照柴油机厂提供的激励数据进行。共振区域的过大振动应力可通过确定主要贡献的谐次分量,调整节点位置部件参数的方法来消减;非共振区域的过大振动属正常的振动响应,可通过增强曲轴的抗扭振疲劳强度来适应,但其可行性应综合考虑柴油机设计因素。

To deal with the excessive torsional vibration excitation force in the torsional vibration calculation of a new type of diesel engine,the excitation was analyzed and torsional vibration calculation was carried out.To reduce excessive torsional vibration compound stress,different methods were tried.The following conclusions were obtained.The diesel engine strengthening index has been improved continuously,but the amplitude of the gas excitation harmonic component recommended by CCS is relatively small.From the perspective of safety,the calculation of torsional vibration should be calculated according to excitation data provided by diesel engine manufacturers.The excessive vibration stress in resonance region can be reduced by determining the harmonic component of the main contributer and adjusting the component's parameters of the node position.Excessive vibration in the non-resonant region is normal vibration response,which can be adapted by enhancing the torsional vibration fatigue strength of the crankshaft,but the feasibility of the diesel engine design should be considered comprehensively.