新研通用挂架前接头螺栓断裂分析

新研通用挂架在进行冲击试验时,3颗30CrMnSiA前接头承力螺栓从根部断裂脱落。对断裂螺栓的宏、微观特征进行观察与分析,并对断裂螺栓的硬度、化学成分进行了检测。结果表明：螺栓断裂性质为剪切过载断裂,断裂深层原因为产品存在设计缺陷即选用成熟设计但未考虑载荷差异,导致强度校核验证不充分;对螺栓头部设计进行改进,取消该螺栓的六方沉孔结构,改为宽、深均为2 mm的一字槽,消除危险截面避免应力集中。新制试验件采用了改进措施后通过了考核,螺栓未出现断裂现象,从而验证了改进措施正确、有效。

Fracture Analysis of Front-joint Bolt of Newly-developed General Pylon

Three front-joint bolts of a newly-developed general pylon fractured near the boot during impact testing.Macro and micro observation,hardness testing,and chemical composition analysis have been performed to find out the cause bolts.The results show that the fracture of the bolts is shear overload facture.Although a mature design was chosen for the bolts,the difference of load was not taken into consideration,resulting in insufficient verification of the strength,which is the main cause for the fracture.A measure was taken to eliminate the stress concentration of the dangerous cross-section,and the experiments show that the improved bolts can avoid the fracture.