基于SAFT提高TOFD检测缺陷长度定量精度的探讨

The Inquiry of Improving Quantitative Accuracy of Flaw Length in TOFD Technique Based on SAFT

摘要: 针对超声衍射时差(TOFD)方法中由于存在甩弧现象导致缺陷长度测量误差大的问题,借助CIVA仿真软件及合成孔径聚焦技术(SAFT),对长度范围5.0~45.0 mm的9个矩形槽的D扫图像进行处理与重建.结果表明,D-SAFT处理技术能够有效降低干扰衍射信号的影响,使缺陷甩弧现象减弱甚至消失,缺陷最大测量误差由处理前的最大5.0 mm降低至0.6 mm.此外,对Farhang等人提出的变角度解卷积(ADD)结合SAFT方法(SAFTADD)在提高TOFD缺陷定量精度上的应用前景进行了展望.

Abstract: In ultrasonic time of fight diffraction (TOFD) inspection,the arcs at the ends of flaws will reduce the quantitative accuracy of flaw length.To solve this problem,numerical simulation with CIVA software was performed,and the synthetic aperture focusing technology (SAFT) was developed to process and reconstruct the D-scan image.Nine rectangular defects with the lengths ranged from 5.0 to 45.0mm were investigated.The results showed that D-SAFT processing technique was effective to weaken the arcs of flaw,and the maximum defect quantitative error was reduced from 5.0mm to 0.6mm.In addition,based on the angle dependent deconvolution (ADD) method combined with SAFT,the improving method of flaw quantitative accuracy in TOFD technique was prospected.