未焊透缺陷尺寸对X80管道弯曲承载力的影响

Infl uence of Incomplete Welding Defects Size on Bending Capacity of X80 Pipeline

为了得到未焊透缺陷尺寸对X80管道弯曲承载力的影响规律,通过有限元计算得到了缺陷深度和长度对失效弯矩的影响规律。结果表明:缺陷处产生明显的应力集中现象,缺陷处Mises应力随着缺陷深度和长度的增加而分别增加;与缺陷长度相比,缺陷深度对Mises应力集中现象的影响更加明显。加载初期,缺陷处Mises应力随着弯矩的增加有一定程度的减小;之后缺陷处Mises应力随着弯矩的增加而增加;当缺陷处Mises应力超过屈服强度进入强化阶段后,缺陷处Mises应力随着弯矩的增加而增加的幅度有所减小。失效弯矩受缺陷深度的影响远远大于缺陷长度的影响。

In order to obtain the influence rule of the size of incomplete welding defects on the bending capacity of X80 pipes,the influence of defect depth and length on the failure bending moment is obtained by finite element calculation.The results show that there was obvious stress concen-tration at the defect,and the Mises stress increased with the increase of the depth and length of the defect respectively.Compared with the defect length,the effect of defect depth on the Mises stress concentration is more obvious.At the initial stage of loading,the Mises stress decreases to a certain extent with the increase of bending moment.The Mises stress increases with the increase of bending moment afterwards.When the Mises stress at the defect exceeds the yield strength and enters the strengthening stage,the increase range of the Mises stress at the defect decreases with the increase of bend-ing moment.The influence of defect depth on failure moment is much greater than that of defect length.