具有裂纹的曲轴-轴承系统动力学与摩擦学耦合分析

Coupling Analysis on Dynamics and Tribology of a Cracked Crankshaft-Bearing System

以实测示功图为计算依据,以4缸柴油机的曲轴-轴承系统为研究对象,应用动力学仿真软件ADAMS耦合分析了具有裂纹的曲轴-轴承系统动力学行为和摩擦学特性,提出了"等效直径法"建立具有不同深度裂纹的弹性曲轴有限元模型.由于裂纹的扩展是曲轴动力学响应的慢变参数,从启裂到曲轴断裂采用线性插值法,分别建立具有不同深度裂纹的曲轴-轴承系统动力学和摩擦学耦合分析ADAMS模型并求解.结果表明,裂纹对其附近的曲轴轴承的动力学和摩擦学性能影响较大,随着裂纹深度的增加,裂纹附近的主轴承反力、最大油膜压力峰值和最小油膜厚度均减小,但曲轴轴颈中心径向振动响应振幅增加.

Multidisciplinary coupling problem between dynamics and tribology is studied for a cracked crankshaft-bearing system in a four-cylinder diesel engine. A special software ADAMS is used and the original calculating data is from the testing indicator diagram of cylinder pressure. Equivalent diameter method was used to establish the finite element model of the elastic crankshaft with crack. Linear interpo- lation method was used to from cracking to breaking of crankshaft. The models were solved by the AD- AMS. Simulation results show that an obvious influence on dynamic behavior of crankshaft and tribologi- cal performance of bearings near cracking is demonstrated. Reacting forces of bearings, maximum pres- sure of oil film and minimum thickness of oil film are decreased with the increase of crack size. While radial vibration amplitude of crankshaft journal centers is increased simultaneously.