Investigation of Lamb waves in solid-liquid layers

Lamb waves are used in non-destructive testing to detect defects or corrosion of walls of pipes or other sensitive constructions. Depending on the used mode of the Lamb wave the propagation of the waves can be influenced by the presence of liquids as it e.g. occurs in liquid filled pipes. The here occurring leaky Lamb waves has therefore already been investigated in the past. In addition also in non-filled pipes liquids can cover the wall either due to condensation out of a saturated gas phase or due to remains of water on a former filled pipe. The liquid would then cover the wall partly as a layer and could also influence the propagation of the Lamb waves. In this paper the propagation of Lamb waves is therefore investigated in partially or fully covered plates with liquid layers showing the damping of the waves at the beginning and along the liquid layers.