Elastodynamics

Summary

Elastodynamics is the study of time-dependent motion of elastic solids, above all of elastic waves. The linear theory adds the inertia term to the equilibrium equations of linear elasticity. Then the displacement obeys a hyperbolic system of partial differential equations. In an isotropic body this system carries two kinds of bulk waves, the faster P-waves and the slower S-waves. Boundaries add surface and guided waves. It is the mathematical basis of seismology, ultrasonic testing and the vibration of structures.