Elastic Waves

Different types of elastic wave can propagate in solids. These waves are classified according to the relationship between the motion of the particles and the direction of propagation of the waves and also according to the boundary conditions. The most common types of elastic wave in solids are: Longitudinal (irrotational) waves, Transverse (shear) waves, Surface (Rayleigh) waves, Interfacial (Stoneley) waves and Bending (flexural) waves. This chapter briefly describes the interaction of waves when they encounter a boundary. Longitudinal waves are those in which the particle velocity is parallel to the direction of travel of the wave. Transverse waves are another common type of wave, in which the particle velocity is perpendicular to the wave's propagation. Surface waves are analogous to gravitational waves on the surface of water. When two semi-infinite media with different material properties are in contact, special waves form at their interface in the case of a disturbance.