柴油机主轴承座的有限元强度分析

对某直列6缸柴油机提高增压压力后主轴承座的结构强度进行了有限元分析。建立了主轴承座的局部模型,其中通过约束接触面对应节点在某些方向的相对位移来模拟接触关系,主轴瓦过盈和螺栓预紧力通过热胀冷缩实现。采用Engdyn软件中曲轴动力学模型与弹性流体动力学润滑相耦合的方法计算主轴承载荷,根据经验确定了5种危险点产生应力峰值的主轴承载荷状况;根据有限元计算结果确定了6个危险点,用Smith图得出了各危险点的疲劳安全系数。结果表明,主轴承座、主轴承盖各危险点安全系数均满足要求。

Strength FEM Analysis on the Main Bearing Wall of a Diesel Engine

Since the boost pressure of a diesel engine is increased,the FEM analysis of the main bearing wall to evaluate the structural strength was conducted.The FEM assembly-model of the main bearing wall was set up,in which contacting faces were simulated by restricting the relative displacement in some directions of the corresponding nodes on the faces,and thermal preloading were applied on the bearings and bolts.The distributing load on the main bearing was computed with Engdyn software by using a dynamic crankshaft model coupling with the Elasto-Hydrodynamic Lubrication(EHL).Then,based on the experience,five load cases were ascertained to describe the max/min dynamic loading during an engine cycle.Consequently,6 points were determined for the calculations of the dynamic safety factor according to SMITH.The results showed that the dynamic safety factor of all the points on main bearing wall or cap met the fatigue requirements.