超声透射时差法固体推进剂厚度及缺陷检测

Defect and Thickness Testing Method for Solid Propellant Based on Time of Ultrasonic Flight Transmission

利用超声透射时差法无损检测原理,结合TDC时间数字测量技术,首次提出仅利用测量时间就可实现固体推进剂厚度及缺陷的多参数检测方法,设计出探头架,分析了超声在推进剂中传播过程,并设计出实验系统。通过对某固体推进剂厚度、径向自然缺陷和轴向人工缺陷检测,厚度测量误差不超过±0.05 mm,缺陷有效阈值为6.0～10.7,结果表明本方法及系统切实可行。理论上,本系统时间测量范围为3.6 ns到200 ms,精度为125 ps,裂缝缺陷分辨率大于0.001 mm。

This paper proposes a kind of testing method,only using measure time,for thickness and defect of solid propellant for the first time. The method uses time of ultrasonic flight transmission principle and time digital convert technology called TDC. The paper also designs probe holder,analyses ultrasonic transmission process in the propellant,and establishes an integrity experimental system. It tests thickness,natural defect in radial direction,and artificial defect in axial direction for a solid propellant on the experimental system. And the thickness measuring error is less than ±0.05mm,and the efficient threshold of the defects is from 6.0 to 10.7. The experimental results demonstrate the method and the system is realistic. Furthermore,theoretically,the time measurement accuracy of the system is 125 ps,the time measurement range of the system is from 3.6 ns to 200 ms,and the resolution of the crack defect is more than 0.001 mm.