钢轨轨头内缺陷的超声相控阵DAC定量方法

DAC quantitative method of ultrasonic phased array for rail head defects

为改善钢轨现行超声检测方法效率低和定量评价难度大的不足,将传统单探头DAC曲线定量方法引入超声相控阵检测领域,研究一种基于超声相控阵全矩阵数据的轨头内部缺陷定量评价方法。对轨头检测断面进行网格划分,模拟各网格节点处缺陷尺寸。利用超声相控阵测量模型,求得各网格节点处的DAC曲线。基于Kriging插值方法,构建轨头缺陷DAC定量评价模型,实现对检测断面内任意位置缺陷的定量评价。通过搭建钢轨超声相控阵检测试验系统,对钢轨人工缺陷试块进行检测试验。研究结果表明:相比工业中常用的-6 d B缺陷定量方法,本文方法在轨头内部缺陷检测精度和效率上均有明显优势。

In order to improve the low efficiency and high challenge in defects quantitative of current ultrasonic testing method for rail, the traditional quantitative method using distance amplitude curve of monolithic transducer is introduced into ultrasonic phased array detection. A method using full matrix data of ultrasonic phased array is studied for quantitative evaluation of rail head internal defects. The detecting section of the rail head is partitioned, a series of defects size at the nodes are simulated, and the distance amplitude curves at the nodes were obtained by the ultrasonic phased array measurement model. The distance amplitude curve quantitative evaluation model of rail head internal defects is constructed based on the Kriging interpolation method, and make it possible to quantitatively evaluate defects of any position in the detecting section. The ultrasonic testing system for rail was built to test the artificial defects in the rail test block. The results show thatthe proposed method has obvious advantages in accuracy and efficiency when detecting defects compared with the commonly used -6dB defects quantitative method in industry.