5A06铝合金钣金支架的振动断裂原因分析

Cause Analysis of Vibration Fracture of 5A06 Aluminum Alloy Sheet Metal Bracket

以某箭体使用的5A06铝合金钣金支架为研究对象,对振动失效区域进行了静载强度有限元仿真计算。采用OM、SEM、EDS对断口裂纹表面进行了分析和显微硬度测试。结果表明：裂纹源起始于钣金支架折弯处外侧面,折弯过程承受的高速冲击与大塑性变形在支架外侧引起了表层微裂纹,在振动过程交变动态载荷持续叠加,折弯边进入塑性状态,在峰值应力作用下产生断裂破坏。

Taking 5 A06 aluminum alloy sheet metal bracket of a rocket body as the study object, FE simulation calculation of the static load strength in the vibration failure region was carried out. The fracture surface was analyzed by OM,SEM and EDS, and the micro-hardness was tested. The results show that the crack source starts at the outer side of the bending of the sheet metal bracket. In the bending process, high velocity impact and large plastic deformation cause the surface micro-cracks at the outside of the bracket. In the process of vibration, alternating dynamic loads continue to be superimposed,and the bending edge enters the plastic state, resulting in fracture failure under the action of peak stress.