TOFD双曲线拟合指针设计

The Design of Hyperbolic Fitting Pointer in TOFD

超声衍射时差法(TOFD)是一种较新的无损检测技术,它利用超声波在缺陷端部产生的衍射信号来实现缺陷的检测和尺寸测量。在TOFD扫查中,由于缺陷衍射信号的传输时间随探头位置的变化而变化,因此在D、B扫描中,点状缺陷和线状缺陷端点都会形成TOFD技术特有的向底波方向弯曲的特征弧形显示,其形状类似双曲线,故将其取名为双曲线拟合指针。根据这一特点提出双曲线拟合指针的数学模型,以模型为基础设计基于微软基础类库(MFC)的双曲线拟合指针算法并实现。双曲线拟合指针可对焊缝缺陷进行定位和定量计算。

The ultrasonic time of flight diffraction （TOFD） is a new non destructive testing method. It measures and determines size of the defect based on the signal diffracted from tips of the defects. Because the transmission time of the diffraction signal change as the probe position changes, the endpoint of dot defect and line defect, in the TOFD-D scan and B scan, will form an arc shape which is peculiar in TOFD. Because its shape is similar to hyperbola, it is also called hyperbolic fitting pointer. Based on the mathematical model, which is put forward according to the characteristics of hyperbolic fitting pointer, an algorithm of the hyperbolic fitting pointer and realization with MFC is designed and implemented. Hyperbolic fitting pointer can position and quantitatively calculate the weld defects.