Harmonic Oscillator Potential to describe Internal Dissipation

Assuming that a constant potential energy function has meaning for a dissipated harmonic oscillator, then an important issue is the time dependence of the turning points. Turning point studies demonstrate that the common model of external (viscous) damping fails to properly describe those many systems where structural (internal friction) damping is the most important source of dissipation. For internal friction damping, the better model of potential energy is one in which the function is not stationary.