微小缺陷的非线性超声检测及其成像技术

Nonlinear ultrasonic testing and imaging for tiny flaw

采用通用超声检测设备并结合高通滤波技术获取了非线性超声的高次谐波信号,并将其用于薄板点焊焊核的微小缺陷检测及焊核的超声C扫描成像中。较之传统超声检测方法,采用非线性高次谐波检测薄板点焊焊核缺陷具有更高的时域分辨率及缺陷敏感度,能够更加准确的确定内部缺陷的位置及尺寸。此外,本研究还采用非线性高次谐波对薄板焊核进行超声成像分析,获得了清晰准确的焊核结构图像。非线性超声检测技术具有更高的检测效力,能够显著拓展检测系统的检测能力。

The higher order harmonic component of nonlinear ultrasonic is obtained by the general ultrasonic testing device with a higher pass filter, and the higher order harmonic wave is adopted into the tiny flaw detection and the ultrasonic imaging of spot welds. The higher order harmonic wave has excellent sensitivity to the tiny flaw and higher resolution in the time domain than conventional ultrasonic wave. Thus, the size and the position of tiny flaw are easier to determine, though the thickness of spot weld is very small. Besides, the nonlinear ultrasonic imaging technique based on the higher order harmonic wave is also presented in the research, and the nonlinear ultrasonic imaging is more effective to investigate the inner constitution of spot weld. The nonlinear ultrasonic has a higher testing effectiveness, and the testing ability of ultrasonic system can be developed.