连杆柔性化处理对机体表面振动及主轴承受力的影响
Diesel Engine Body Vibration and Main Bearing Force Analysis when using Flexible Connecting Rod

为了探究连杆的弹性变形对机体表面振动的影响，运用AVL-EXCITE Designer软件对某六缸柴油机进行多体动力学分析，建立了缸体、曲轴、连杆的有限元模型，并对缸体、曲轴的有限元模型进行模态分析及实验验证，确保了模型的准确性。通过发动机表面不同位置处选取点的振动加速度来评价连杆分别采用刚性体和柔性体对机体表面振动的影响。结果显示，对比连杆为刚性情况，弹性因素存在的情况下，缸体上各个分析点的加速度值都有一定的下降，并且在峰值处波动程度明显下降。于此同时，连杆柔性化处理使得主轴承方向受力变小，并且最小油膜厚度在峰值处也会变小。所以，在仿真中连杆的柔性化使得仿真更符合真实情况，探究其对机体表面振动的影响将有助于低噪声柴油机的研发。
In order to explore the influence of the elastic deformation of connecting rod on engine block surface vibration, multi-body dynamics analysis is used in this paper. First, a model of an in-line 6-cylinder diesel engine is built by AVL EXCITE Designer, including the finite element model and simulation model of cylinder block, crankshaft and connecting rod. Then, modal analysis and experimental verification are carried out to ensure the accuracy of the simulation model. Through the vibration acceleration of different locations selected in the model, engine block surface vibration is evaluated respectively for using rigid connecting rod and flexible connecting rod. According to the simulation results, the acceleration of each analysis point on the body has a certain decline, and fluctuations in the peak are also significantly reduced when considering the flexible connecting rod. Results also show that using flexible body makes main bearing stress decrease at piston movement direction, and the minimum film thickness at the peaks becomes smaller. A much satisfactory agreement of simulation and measurement results can be achieved when considering flexible connecting rod