Fundamentals and Analysis of Lamb Waves

The antecedent work on Lamb waves is not hard to identify. It was Lord Rayleigh in 1889 who first explained wave propagation along a guided surface [1], and the waves are known as Rayleigh waves today. Following Rayleigh's work, Horace Lamb, a British applied mathematician, reported the waves discovered in plates in one of his historic publications, On Waves in an Elastic Plate, in 1917 [2], and the waves were named after him as Lamb waves. Horace Lamb also established the theoretical rudiments of such waves. Lamb waves did not attract great attention because of the extremely complex equations needed to describe them, until Osborne and Hart revisited this topic in 1945 to examine Lamb waves activated in structures in underwater explosions [3]. Their study unveiled much potential for applications of Lamb waves. A comprehensive solution to Lamb waves was completed by Mindlin in 1950, followed by considerable detail provided by Gazis in 1958 [4] and Viktorov in 1967 [5] who also first evaluated the dispersive properties of Lamb waves. Firestone and Ling inaugurated Lamb-wave-based damage detection in the 1940-1950s [6, 7], after which Lamb waves found niche applications in seismology and nondestructive evaluation (NDE). In parallel with theoretical development, intensive experimental investigation, for the purpose of understanding fundamentals of Lamb waves, was contributed by Worlton in 1961 [8] and Frederick and Worlton in 1962 [9]. With advances in computing devices, the period from the 1980s until the present day has witnessed unprecedented prosperity of Lamb-wave-based engineering applications, in particular Lamb-wave-based damage identification techniques in recent years [10-22].