膨胀管残余应力测试

膨胀管残余应力是影响膨胀管抗外挤、内压强度的重要因素之一。确定膨胀管的残余应力，测试方法至关重要。在常用测试方法中，机械测量法中的盲孔法体现出测试的优越性。应用盲孔法测试J55、K55两种规格膨胀管的残余应力，并根据实际测试的应力水平和实验误差，采用应变释放系数分级法对试验结果进行修正，以提高测试结果的精度。实验结果表明，膨胀管膨胀后存在环向、轴向的残余应力，且外表面总是压残余应力。将实验结果与仿真结果对比，误差满足工程要求，说明盲孔法测试膨胀管残余应力方便、快捷、准确、有效。

Residual Stress Test of Expansion Casing

Residual stress in expansion casing is one of important factors affecting its squeezing and pressure resistance. In order to determine residual stress in an expansion casing, the testing method is essential. Among common testing methods, the hole-drilling method has superiority in mechanical measurements. Residual stress in expansion casings with J55 and K55 two specifications were tested respectively by hole-drilling method. According to the actual tested stress level and trial errors, the trial results were revised using relieved strain coefficients grading method to improve the test precision. Test results show that an expanded expansion casing exits circumferential and axis residual stress, and its outer surface has always compression residual stress. Comparing trial results with that from simulation, the errors met the engineering requirements, which indicates that the hole-drilling method is convenient, fast, accurate and effective.