| 后纵臂的断裂原因分析 |
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| 引用本文： | 赵凯,刘新灵,曹金华,陈星.后纵臂的断裂原因分析[J].失效分析与预防,2020,15(6):404-409, 414. |
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| 作者姓名： | 赵凯 刘新灵 曹金华 陈星 |
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| 作者单位： | 1.中国航发北京航空材料研究院，北京 100095 |
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| 摘 要： | 汽车在试验场行驶21 000 km后发现后纵臂断裂，该类后纵臂曾多次发生断裂故障。后纵臂在使用过程中受拉、压、扭等复杂载荷。通过对后纵臂进行外观观察，对其断口进行宏、微观观察，并对后纵臂进行金相组织检查、硬度检查及有限元模拟，确认后纵臂的失效性质，并分析其断裂原因。结果表明:后纵臂的失效性质为疲劳断裂；后纵臂的断裂过程为:在压应力作用下后纵臂中间安装孔处首先发生失稳变形，当后纵臂再次受拉时最大应力转移到中间安装孔处，在交变载荷的作用下发生疲劳开裂。适当增加后纵臂的厚度以提高其刚度，厚度增加后的后纵臂未再发生过类似的断裂故障。
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| 关 键 词： | 后纵臂 BR600钢 疲劳断裂 失稳变形 刚度不足 |
| 收稿时间： | 2020-08-19 |
Fracture Cause Analysis of a Back Trailing-arm |
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| ZHAO Kai,LIU Xin-ling,CAO Jin-hua Jin-hua,CHEN Xing.Fracture Cause Analysis of a Back Trailing-arm[J].Failure Analysis and Prevention,2020,15(6):404-409, 414. |
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| Authors: | ZHAO Kai LIU Xin-ling CAO Jin-hua Jin-hua CHEN Xing |
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| Abstract: | The fracture of the back trailing-arm of a vehicle was found after driving 21000 km in the test site. These back trailing-arms were broken for many times. The back trailing-arm was suffering complex loads such as tension, pressure and torsion during operation. Based on observing the appearance of the back trailing-arm, macro and micro appearance observation, metallurgical structure inspection, hardness, finite element analysis and the cause was found. The results showed that the fracture of the back trailing-arm was fatigue fracture. The fracture process of the back trailing-arm was as follows: Buckling deformation occurred at the middle mounting hole of the back trailing-arm under the action of compressive stress. When the back trailing-arm was suffering the tension again, the maximum stress was transferred to the middle mounting hole, and fatigue cracking occurred under the alternating load. The thickness of the back trailing-arm was appropriately increased to improve its stiffness. No similar fracture failure occurred in the back trailing-arm after the thickness was increased. |
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