柴油机负荷对曲轴疲劳寿命影响的三维有限元分析

3D finite element analysis on effect of diesel engine load on fatigue life of crankshaft

为评估超载运行对柴油机的不利影响,以某型柴油机组成的动力装置为原始模型,设定柴油机发火顺序﹑活塞所受气体力﹑转速和输出扭矩等边界条件,用三维有限元动应力分析和疲劳寿命计算技术计算曲轴在420°缸排插入角下75%负荷、100%负荷、110%负荷和120%负荷时的疲劳寿命.结果表明在420°缸排插入角下,柴油机负荷越高,曲轴单拐的疲劳寿命区域扩大就越明显.

To evaluate the adverse effects on diesel under overload operation, taking the power plant of a certain type of diesel engine as the original model, the crankshaft fatigue life under 75%, 100%, 110%, 120% loads is calculated using dynamic stress analysis and fatigue life calculation of 3D finite element when the cylinder cut-in angle is 420°. The boundary conditions of diesel engine such as ignition sequence, gas force on piston, speed, output torque and so on are set for the calculation. The results show that the fatigue life area of crankshaft throw expands obviously with the increase of diesel engine load when the cylinder cut-in angle is 420°.