Choi Sungho, Cho Hwanjeong, Lissenden Cliff J
Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA.
Sensors (Basel). 2016 Dec 22;17(1):5. doi: 10.3390/s17010005.
Harsh environments and confined spaces require that nondestructive inspections be conducted with robotic systems. Ultrasonic guided waves are well suited for robotic systems because they can provide efficient volumetric coverage when inspecting for various types of damage, including cracks and corrosion. Shear horizontal guided waves are especially well suited for robotic inspection because they are sensitive to cracks oriented perpendicular or parallel to the wave propagation direction and can be generated with electromagnetic acoustic transducers (EMATs) and magnetostrictive transducers (MSTs). Both types of transducers are investigated for crack detection in a stainless steel plate. The MSTs require the robot to apply a compressive normal force that creates frictional force coupling. However, the coupling is observed to be very dependent upon surface roughness and surface debris. The EMATs are coupled through the Lorentz force and are thus noncontact, although they depend on the lift off between transducer and substrate. After comparing advantages and disadvantages of each transducer for robotic inspection the EMATs are selected for application to canisters that store used nuclear fuel.
恶劣环境和狭窄空间要求使用机器人系统进行无损检测。超声导波非常适合机器人系统，因为在检测各种类型的损伤（包括裂纹和腐蚀）时，它们能够提供高效的体积覆盖。水平剪切导波尤其适合机器人检测，因为它们对与波传播方向垂直或平行的裂纹敏感，并且可以通过电磁超声换能器（EMAT）和磁致伸缩换能器（MST）产生。研究了这两种换能器在不锈钢板中检测裂纹的情况。磁致伸缩换能器要求机器人施加一个产生摩擦力耦合的压缩法向力。然而，观察到这种耦合非常依赖于表面粗糙度和表面碎屑。电磁超声换能器通过洛伦兹力耦合，因此是非接触式的，尽管它们依赖于换能器与基底之间的提离距离。在比较了每种换能器用于机器人检测的优缺点之后，选择电磁超声换能器应用于储存用过核燃料的罐。
