【摘要】 焊缝可靠的性能是膨胀波纹管技术成功应用的关键因素之一。针对膨胀波纹管焊缝检测方法和性能评价标准缺失的现状,引入了数字化X射线平板成像技术。结合图像处理软件实现了波纹管焊缝缺陷的检测,可准确检测出缺陷的类型、尺寸及所处的位置,检测精度可达到0.01 mm。分析了气孔型、未焊透型和裂纹型这三种缺陷分别在焊缝的凹区和肩区时,缺陷的轴向宽度、径向深度、环向长度等参数对膨胀性能的影响,给出了30 MPa膨胀压力下的临界失效尺寸。人为地在焊缝上制备了特定尺寸的缺陷,通过水力膨胀试验,验证了计算结果的可靠性。该研究成果为膨胀波纹管的焊缝质量提供了检测方法,为焊缝性能的评价提供了依据。更多还原

【Abstract】 Weld’s performance is one of the key factors that determine the application success of solid expandable profile liner technology. So far,there is no method of weld defects detecting and evaluation basis. X-ray digital imaging system combined with image processing software is used to detect welding defects. The technology can accurately detect the type,size and location of defects and the detection accuracy can reach 0. 01 mm. Three kinds of typical weld defects,gas pore,incomplete penetration and crack,were analyzed to impact on the performance of the expansion. According to crack opening displacement,the article calculated failure load of crack weld based on the method of extended finite element method and found out failure load of weld with gas pore and incomplete penetration by using nonlinear finite element method. The critical size was gained that could cause weld leakage at 30 MPa pressure. Some artificial specific defects were processed on welds and welds’ expansion properties were tested by hydraulic pressure. Test results verify that calculation results are reliable. The research results provide a method for the weld defects detection of solid expandable profile liner technology and provide the basis for the weld performance evaluation.更多还原