大型铝合金风机叶片断裂原因

Cause of Fracture on Large Aluminum Alloy Fan Blade

某地铁隧道轴流风机叶片在运行过程中断裂,通过化学成分分析、宏微观分析及力学性能测试等方法对叶片的断裂原因进行了分析。结果表明:铝合金风机叶片发生了疲劳断裂。断裂的主要原因是叶片内部存在大量粗大的氧化皮夹渣以及疏松、针孔缺陷,而叶片根部是叶片应力集中区域,此处存在缺陷会导致疲劳裂纹萌生。在离心力和气动力的作用下,叶片根部承受拉力、弯曲和扭转作用力,疲劳裂纹会在这种复合应力的作用下扩展,最终导致叶片快速断裂。

The blade of axial flow fan in a subway tunnel fractured during operation. The causes of fracture on blade were analyzed by means of chemical composition analysis, macro and micro analysis, mechanical property test. The results show that the aluminum alloy fan blade had fatigue fracture. The main reason for the fracture was that there were a lot of coarse oxide inclusions, loose and pinhole defects in the blade, and the root of the blade was the stress concentration area of the blade, the defects on the root of blade led to the initiation of fatigue cracks. Under the action of centrifugal force and aerodynamic force, the root of blade bore tensile force, bending force and torsion force, and the fatigue crack would expand under the action of this composite stress, which eventually led to the rapid fracture of blade.