Guided waves group and energy velocities via finite elements

In this note numerical sensitivity of a wave finite element approach and its post processing for group velocities and energy velocities estimation is dealt with. Precisely, aliasing effects is discussed first. Calculation of guided waves group velocity through a numerical procedure is given. A wave track versus frequencies criteria is employed. Energetics of multi-mode guided wave propagation is also discussed. Analytical expressions of energy velocities are provided. Energy velocities are compared to group velocities, and the sensitivity of energy velocities to the finite element system characteristics is discussed.