船用淡水泵泵轴开裂的仿真分析及改进

针对某船用淡水泵泵轴开裂故障，建立泵轴有限元模型，并采用应力-疲劳理论和线性累积损伤模型，基于安全系数法分析了泵轴的高周疲劳损伤。结果表明:泵轴键槽为结构疲劳薄弱区域，疲劳安全系数不足导致键槽处产生疲劳裂纹,裂纹扩展,直至开裂失效。仿真和试验验证表明:取消键槽并加大轴径的改进措施成效显著；泵轴的疲劳安全系数得到提高，满足材料的许用要求。

Simulation Analysis of the Crack on aMarine Freshwater Pump Shaft and its Solution

To deal with the crack on a marine freshwater pump shaft, finite element model of the pump shaft was established. Then the high cycle fatigue damage of the pump shaft was analysed by using the stress-fatigue theory and the linear cumulative damage model based on the safety factor method. The results showed that the cracking reason of the pump shaft was that the key groove was the weak area of fatigue, and the fatigue safety factor was insufficient, which led to fatigue cracks at the groove, the crack grow and the groove failure occured. Simulation and tests results verifies that the improvement design of removing the key groove and increasing the shaft diameter has achieved good results, the fatigue safety factor of the pump shaft is improved and meets with the material requirements.