为了研究爬波在厚壁管内壁的形成机理，采用激光超声可视化技术，观察直探头在厚壁管外激励时，超声波在厚壁管上的传播过程。结果表明：直探头在管壁上既能形成能量较强的纵波，也能形成能量较弱的横波；当超声纵波声束以接近临界入射角的方式入射到厚壁管内壁时，形成爬波；超声纵波和横波在管内壁上都产生了模态转换现象。该研究为厚壁管内壁缺陷的爬波快速无损检测提供了参考。

The formation mechanism of creeping waves on the inner surface of thick pipes was studied. The laser ultrasonic visualization technique was conducted for observing the propagation of ultrasonic waves on the thick pipes when a straight probe was excited on the outer surface. It was found that the straight probe excites the longitudinal waves with high energy and the shear waves with low energy, and that the creeping waves are formed when the longitudinal waves are incident on the inner surface with a critical angle. Moreover, the mode transformations occur when the longitudinal waves and the shear waves are incident on the inner surface. This study provides experimental references for nondestructive testing the inner surface of thick pipes by using creeping waves.