基于磁记忆检测的汽车退役曲轴剩余疲劳寿命测评技术

Retired Crankshaft Remaining Life Evaluation Based on the Principle Ofmetal Magnetic Memory Technology

利用J-A模型,对曲轴疲劳的磁记忆信号进行分析。结果表明,在交变应力作用下,曲轴磁记忆信号呈一封闭的环线,其面积随疲劳程度增加而增大。曲轴磁记忆信号切向分量的最大与最小值之差,即ΔB能较好的反映曲轴的疲劳程度。实验表明,在疲劳过程中,ΔB大致呈三个阶段,并大致与裂纹扩展的过程相对应。通过检测ΔB值,能够对曲轴的剩余寿命进行评估。

With the use of J- A model, this article analyzes metal magnetic memory signal of crankshaft＇ s fatigue. Results showed, under the influence of alternating stress, metal magnetic memory signal formed a closed loop, also, the loop area increases with increased fatigue degree. △B, the difference between the maximum and the minimum tangential component of the metal magnetic memory signal, can well reflect fatigue degree of crankshaft. Experiments showed that, in the process of fatigue, △B roughly formed three stages, corresponding to the entire crack propagation process. The residual life of crankshaft can be evaluated by examing △B.