板壳结构中的非线性兰姆波

鉴于常规超声检测技术对分布式材料细微损伤和接触类结构损伤的检测效果不佳,近年来非线性超声技术逐渐引起广泛关注.超声波在板壳结构中通常以兰姆波的形式进行传播,然而由于兰姆波的频散及多模特性,使得非线性兰姆波的理论和实验研究进展缓慢.本文从经典非线性理论出发,总结了源于材料固有非线性诱发的非线性兰姆波的理论和实验两个方面的研究进展,井综述了兰姆波的二次谐波发生效应在材料损伤评价方面的若干应用;从接触声非线性理论出发,讨论了目前由于接触类结构损伤诱发的非线性兰姆波的研究现状.最后展望了非线性兰姆波的未来研究重点及发展趋势.

Nonlinear Lamb waves in plate/shell structures

In view of the fact that conventional ultrasonic detection technology is not effective for the detection of distributed fine damage and contact-type structural damage in materials, nonlinear ultrasound technology has been attracting more and more attention in recent years. Ultrasonic waves propagate in the form of Lamb wave modes in the structure of plates and shells. However, due to the dispersion and multimode characteristics of Lamb waves, the progress of theoretical and experimental research on nonlinear Lamb waves is slow. Based on the classical nonlinear theory, this paper summarizes the theoretical and experimental research progress of nonlinear Lamb waves induced by the inherent nonlinear-ity of material, and summarizes the application of the second harmonics of Lamb waves in damage evaluation of material. The current status of the research on nonlinear Lamb waves induced by contact-type structural damage is discussed based on contact acoustic nonlin-earity. At the end, this paper envisions the future research topics and trends in nonlinear Lamb waves.