针对大管径、高温管道, 提出了机械夹持与耦合剂的组合耦合方法, 设计出一种适用于磁致伸缩传感器的柔性机械夹持装置。该柔性机械夹持装置可提供较强的预紧力, 并保证铁钴合金带与被测管壁间的作用力沿环向均匀作用。对比测试结果表明, 干耦合方式不受管道温度限制, 激励的导波能量与信噪比和采用环氧树脂粘贴耦合方式相当。利用课题组研制的MsTGW磁致伸缩导波管道检测仪, 将干耦合式磁致伸缩传感器应用于工程检测中, 可以有效定位出大管径、高温管道中的特征结构及缺陷位置, 定位误差小于5%。所设计的机械夹持装置在工程现场中安装使用方便, 具有很好的工程应用前景。

A combined method using both liquid couplant and mechanical clamping is proposed for magnetostrictive sensor to inspect large diameter and high temperature pipelines. The tailor-made flexible clamping structure was devised for applying strong pressure onto the MsS strip to ensure that the interaction force between the iron-cobalt alloy strip and tested pipe surface evenly distributes along the circumferential direction. The presented coupling method is unaffected by the pipeline temperature. The MsS employing this coupling method can generate equivalent guided wave energy to that of a MsS pasted onto the pipe surface using epoxy. Then, the presented dry-coupled MsS is applied for practical inspections based on the developed MsTGW inspection system. The experimental result obtained from large diameter and high temperature pipelines show that the dry-coupled MsS-based guided wave technique can locate the positions of the featured structure and defects with an error less than 5.00%. The presented flexible clamping structure has good application prospects because it can be easily installed onto the tested pipeline surface.