基于拉-拉疲劳实验,利用磁记忆检测仪监测了抽油杆试件疲劳裂纹扩展的整个过程,提取了表征应力集中程度的磁信号合成梯度极限状态系数指标;并结合有限元方法计算了裂纹尖端的断裂力学参量,得到不同裂纹长度所对应的应力强度因子.结果表明:基于实验数据和仿真结果所建立的磁记忆信号特征指标与应力强度因子之间具有很好的一致性,可以有效反映疲劳裂纹的扩展过程以及累积损伤,为再制造前的毛坯筛选提供理论依据.%The whole crack propagation process of sucker rod specimen was monitored by magnetic memory testing instrument on the basis of tension-tension fatigue experiments ,and the synthetic gradient limit coefficients of magnetic signal characterizing stress concentration degree were extracted simultaneously .The fracture mechanics parameters of crack tip were computed by finite element method ,and the stress intensity factors corresponding to different crack lengths were obtained .The results showed that the characteristic parameters of magnetic memory signal based on experimental data are in accordance with the stress intensity factors calculated by finite element simulation ,which can reflect the fatigue crack propagation process and cumulative damage effectively , providing theoretical reference for blank selection before remanufacturing .
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