Lamb waves

Summary

Lamb waves are elastic waves guided by a thin plate with free faces. Their particles move in the plane spanned by the direction of travel and the normal of the plate. They come in two families of modes, symmetric and antisymmetric about the mid-plane, and each mode is dispersive. Horace Lamb derived their dispersion relations in 1917. They are widely used to inspect plates and pipes for cracks and corrosion with ultrasound.