内燃机曲轴系振动响应的多体系统动力学分析方法

MULTISIDED SYSTEM DYNAMIC ANALYSIS OF THE CRANKSHAFT VIBRATION RESPONSE IN I. C. ENGINES

介绍了运用多体系统动力学进行内燃机曲轴系振动响应分析的方法。通过综合运用 CAD建模、有限元分析以及机械系统仿真等技术 ,可以建立包括曲轴柔性体以及随曲轴一起转动的零件刚性体在内的整个曲轴系的模型 ,计算零件间的相互作用 ,分析曲轴的动态变形。建立了某车用内燃机曲轴系的多体系统动力学模型 。

This paper intends to present a thorough vibration analysis of the crankshaft system in the combustion engine in hoping to improve its working safety and reliability. As the result of our investigation on the basis of the application of elastic wave theory and discrete system analysis it has also proved that the method of calculating the crankshaft vibration response by using the multisided system dynamics is practical and technically favorable. The method helps to join the model of the whole system including crankshafts and the rotating parts, such as pistons, connecting rods and the other factors concerned together, and calculate the interaction between parts directly. Modeling crankshafts as flexible bodies as is done by using our method has also enabled us to take into account their deformation, the vibration response included. The present paper has also made a detailed discussion on how to build up the so called multisided system dynamics model and how to simulate the crankshaft system by integrating the CAD, FEA and MSS technologies in a comprehensive way. The mass properties and geometry of rigid bodies can be derived from CAD modeling. The description of flexible bodies can be generated through finite element modeling and modal analysis. Thus, the whole model can be established by putting all the parts concerned together while considering various constraints involved with its dynamic performance simulated dynamically after applying the external forces. As a practical example, a vehicle's crankshaft system model is provided with its vibration response parameters illustrated.