螺旋桨激振力作用下主机曲轴动力学分析

Dynamical analysis of crankshaft with propeller excited vibratory force

以某船用柴油主机曲轴为研究对象,建立了该船推进系统的非线性多体动力学模型,在考虑螺旋桨载荷作用下对该推进系统进行了动力学计算.分析了曲轴的受力及位移随曲柄转角的变化情况,并与只考虑柴油主机的动力学模型的计算结果进行了比较.结果表明,曲轴各轴颈受力最大值出现时刻与对应气缸最大爆发压力时刻基本一致,螺旋桨载荷使曲轴输出端相对角位移最大值增加66%,且明显加剧了轴向位移的波动.

The crankshaft of a marine diesel engine is investigated in this paper. The FE-models of propulsion system is created, and the multi-body dynamics model of the propulsion system is established, and calculation is performed where the affects of shaft and propeller excited force is considered. The dynamic behavior of crankshaft is investigated of a complete engine cycle, such as the force and the displacement, and compared with the dy- namics results of the crankshaft system. The results show that the time when maximum force of journal appears is consistent with that when maximum cylinder pressure occurs. The propeller exciting force increases the relative angular displacement of the drive end by approximately 66%, and the oscillation of axial displacement is intensi- fied obviously.