油气管道平滑凹陷疲劳试验应变响应分析

Strain Response Analysis of Smooth Depression of Oil and Gas Pipeline for Fatigue Test

将含深度15%OD平滑凹陷的试验管段进行疲劳试验,并监测凹陷不同部位的应变响应,结果表明:疲劳失效位置出现凹陷边缘位置,失效方式为轴向疲劳裂纹;凹陷中心在疲劳试验过程中,环向受拉,轴向受压;凹陷轴向中间位置和45°中间位置,环向和轴向均为拉应变,而凹陷环向中间位置,环向为拉应变,轴向为压应变;凹陷轴向边缘的环向和轴向均受压,45°边缘的环向和轴向均受拉,而环向边缘在疲劳试验过程中环向受压,轴向受拉。

The fatigue test of the test pipeline with 15%OD smooth depression was carried out,and the strain response of different parts of the depression was monitored.The result shows that:the fatigue failure position appears in the edge of the depression,and the failure mode is an axial fatigue crack.In the process of fatigue test,the ringl direction of the center of the depression is under tension and it’s axial direction is under compression.In the middle of the center and edge of the depression,axial position and 45°position,the circumferential and axial strain are tensile,but the circumferential strain of the ring direction is tensile,and the axial strain is compressive.The circumferential and axial strain of the axial edge of the depression are both compressive,and the circumferential and axial strain of the 45°edge of the depression are both tensile,while the circumferential strain of the ring direction edge is compressive and it’s axial strain is tensile.