四缸内燃机曲轴-飞轮组结构模态分析

Structural Modal Analysis for the Crankshaft/flywheel component of a 4-cylinder IC Engine

应用Pro/Engineer软件建立了某四缸内燃机的曲轴-飞轮组的三维实体模型,在此基础上应用ANSYS软件对其进行了有限元结构模态分析。研究结果表明:曲轴-飞轮组的结构振动模态在低频段为整体、同步的简单弯曲、扭转振动模态,在高频段为各部分不同步的弯曲、扭转或弯扭组合振动以及复杂的局部振动;以弯曲、扭转及弯扭组合为主要特征的曲轴-飞轮组各阶振动模态极易被作用在曲柄销上的连杆冲击力所激发,因此,在对内燃机曲轴-飞轮组进行设计时,需要在模态分析基础上对其动力学特性进行优化,以保证内燃机获得良好的动力学性能。

The three dimensional solid model of the crankshaft/flywheel component of a certain 4-cylinder engine is established using the Pro/engineer software, on the basis of which, the structural modal characteristic is analyzed using the ANSYS software. It is demonstrated that： 1） The structural modes of crankshaft/flywheel component in the low frequency range represent the torsional or bending modes of the whole component; while in the high frequency range, the modes show primarily the local and out of step vibration indifferent position.. 2） The crankshaft/flywheel modes having torsional or bending mode shape is very possible to be excited by the impact forces from the connecting-rods, so it is essential to optimize the dynamical characteristic of the crankshaft/flywheel component.