模拟内燃机曲轴振动的新模型

采用有限元法，对内燃机曲轴的三维振动特性进行了数值模拟。结合曲轴的结构特点，采用考虑剪切变形和转动惯量的Timoshenko空间梁单元建立曲轴结构有限元模型。对飞轮采用实体单元进行网格划分，并提出连接两类单元的方式。以一直列式四缸发动机曲轴为例，介绍建立模型的方法和过程，并对其振动特性进行分析，分析结果与相关研究和实验数据进行了对比，进一步模拟了计算此曲轴动态振动响应。

New Model for 3D Vibration of Internal Combustion Engine(I.C.E.) Crankshaft

Based on FEM, 3D Vibration characteristics of I.C.E. Crankshaft are investigated. Two innovations are proposed in this paper.First,considering the structure of crankshaft,three-node and quadratic Timoshenko beam element is employed to model the engine crankshaft, which includes the effects of transverse shear and accounts for the initial curvature of the beams. Second, The flywheel is meshed by solid element, and an apt connection of beam element and solid element is presented. A four-inline cylinder crankshaft is used as an application example to demonstrate the modeling method, and the natural frequency of free system and supported system are determined. Then, the results are compared with those determined analytically and experimentally values available in some publications. Finally, the operating crankshaft is simulated in three-dimensional and the harmonic response is calculated and analyzed.