连续油管疲劳损伤的磁记忆检测试验研究

连续油管工作在大位移塑性变形条件下，受力复杂，工况恶劣。其破坏形式多种多样，尤以疲劳居多。根据连续油管的工作原理，利用磁记忆检测方法，进行连续油管全尺寸疲劳试验，研究连续油管在内压、轴向拉伸及弯曲等交变载荷作用下，疲劳破坏过程的磁记忆特征信号变化规律，采用区域积分面积-寿命关系曲线，分析大位移塑性变形下的连续油管疲劳损伤过程的磁记忆信号特征值的规律。试验表明:磁记忆特征值可以很好的描述连续油管疲劳损伤程度，为现场连续油管服役过程工作寿命及损伤程度的判定提供依据。

Experimental study on fatigue damage of coiled tubing based on metal magnetic memory testing

Coiled tubing is serving under the severely plastic deformation, with complexity stresses and the worst condition, and the failure modes are various. In this paper, according to the working principle of the coiled tubing, a full sized scale experiment for coiled tubing was performed by using metal magnetic memory testing method(MMM). The laws of signal characteristics for MMM during the fatigue damage of the coiled tubing under severely plastic deformation was analyzed. It showed that the signal characteristics of MMM can describe the fatigue damage of coiled tubing, which can provide a reliable method for the working life and the damage degree of the coiled tubing when it is serves on the oilfield.