This is a simple(?) problem but my ability to perform basic calculus disappeared long ago. I am working thru the equations for a spring response to a dropped weight. My primary reference is Shigley (for just about everything!!) and I've validated the eqn's for deflection and max force. However, I am trying to work out the duration of the event for purposes of estimating simulation time in explicit FEA. Solving for time to max deflection from eqns in Shigley yields exactly 1/200th of the time reported by 2 mechanism simulation tools...who nail the deflection and force as noted above. Has anyone solved this "compression time" and, if so, can you share the eqn?