基于二阶多项式模型的焊缝缺陷几何量定征技术

A Geometric Quantity Characterization Technique for Weld Defect Based on Second Polynomial Model

为了解决超声TOFD成像难以精确测量缺陷位置及其尺寸的问题,提出了一种基于二阶多项式模型的焊缝缺陷几何量精确定征技术。在分析焊缝缺陷超声TOFD成像特性的基础上建立超声TOFD检测图像的参数化模型,并采用模型与实测数据之间的代数距离作为优化目标函数,将非线性的参数估计转换为线性的矩阵求解问题,在精确获取焊缝缺陷的尺寸及其位置等几何量信息的同时还能够大幅度地提高缺陷几何信息参数的估计效率。仿真与实验结果显示误差均在5%以内,表明了该定征方法的可行性和有效性。

In order to overcome the problem that the geometry information can not be measure accurately,a geometric quantity characterization technique for weld defect based on second order polynomial model is proposed.The parameterized model of ultrasonic TOFD detection image is established by analyzing its characteristics,and the algebraic distance is used as optimization objective function,the nonlinear parameter estimation can be converted into linear matrix to solve the model,thus the location and the size of the weld defect can be obtained accurately,meanwhile,the efficiency of above defect parameters estimation can be improve greatly.The errors of simulation and experimental results are all less than 5％,which demonstrate the proposed method is feasible and effective.