Coulomb Damping - Page 5
Figure 8 Velocity versus displacement.
Figure 8 shows the nonlinearity introduced with small joggles where the friction
ratcheting occurs.
Figure 9 displacement.versus time
Figure 9 is useful as we can check the damping force due to friction by
measuring successive displacement half peaks.

x1-x2 = 2*Fd/k   where x1, x2 are successive half peaks, Fd is the friction
force and k is the spring stiffness.

In this case the approximate solution is Fd = 134.9 lbf versus the actual input
of 126 lbf. Inaccuracies are due to the fact that the actual peak values are not
present in the output.

If the mass of the system under 1g is responsible for the friction force, then this
equates to a friction coefficient of 0.349