超声导波波包宽度与管材内径-壁厚比的关系

The Relationship Between the Wave-Packet Duration of Ultrasonic Guided Waves and the Inner-Radius-Thickness Ratio of Pipes

在自由管材的情况下,在各传播距离、各频厚积和各激发脉冲周数上,分析了内径-壁厚比和管材中较低阶纵向导波模式波包宽度的关系.分析结果表明:当内径-壁厚比较小时,内径-壁厚比的变化对各导波模式的波包宽度有较大影响,但随内径-壁厚比的增加,这种影响将减小;内径-壁厚比对导波波包宽度的影响随导波模式阶次的增加而减小.另一方面,对于不同内径-壁厚比的管材,检测中应当用不同的导波模式,所用的激发脉冲周数和频厚积也应当不同.

The relationship between the wave-packet duration of ultrasonic longitudinal guided waves with lower order and the inner-radius-thickness ratio(IRTR)of free pipes was analyzed at various propagation distances, various frequency-thickness products and various cycle numbers of the input pulse signal. The results show that when IRTR is smaller, the change of IRTR has a greater influence on the wave-packet duration of guided waves; but with the increase of IRTR, the influence of IRTR on guided waves will be reduced. The influence of IRTR on guided waves will also be reduced with the increase of the order of guided waves. On the other hand, for pipes of different IRTR, one should select different modes, and choose different cycle numbers and different frequency-thickness products.