针对厚壁管道,提出一种快速检测缺陷的周向导波检测法,计算了外径269 mm、壁厚32 mm的厚壁管道中周向Lamb波的频散曲线,分析了探头频率和压电晶片尺寸对检测的影响;搭建了试验平台,对缺陷进行了检测与成像.试验结果表明,周向Lamb波能对缺陷进行长距离检测,实际检测时应选择较低频率和较大尺寸的压电晶片,而且周向Lamb波在厚壁管道的传播过程中轴向声束比较集中,可通过B扫成像进行损伤评估.

In this paper,circumferential guide wave detection method was presented,which could detect thick walled pipe defects rapidly.Dispersion curves of circumferential Lamb wave in thick walled pipe with 269mm outside diameter and 32mm wall thickness was calculated firstly.Then experimental system was built.Studies were made of the effect of frequency and size of piezoelectricity crystal on the detecting results,and imaging research on defect was carried out.The experimental results indicated that circumferential Lamb wave could detect flaws for a long distance.It is better to select low frequency and larger size of piezoelectricity crystal in practical testing.Axial acoustic beam of circumferential Lamb wave is concentrated in thick walled pipe.And it can evaluate damage through B scan imaging.