Damping in Nonlinear Transient Analysis

Hi everybody,

I am currently trying to better undestand the introduction of damping in nonlinear transient simulations.

I set up a simple model composed by a cantilever beam which is released from a bent condition and let free to vibrate.

Since I would like to gain some confidence with the Rayleigh damping (and the correct use of the coefficients alpha and beta) I tried to find the critical damping condition for my structure, but actually I found out that every effort to introduce damping into the model turned out to be ineffective: the model remains undamped.

I tried to impose damping in the following ways (not simultaneously, obviously):

1. PARAM ALPHA1 and ALPHA2. The corresponding values where identified by imposing one of the two equal to zero and finding the value for the other in order to have a critical damping condition and for a frequency of interest equal to the first natural frequency of the beam, identified through a modal analysis. No effect on the nonlinear transient response.
   
   
2. Use of structural damping PARAM G and conversion into equivalent viscous damping through the use of PARAM W3, which, according to the manual, should be supported for nonlinear transient analysis. W3 was found converting the first natural frequency in radians per second. No effect on the nonlinear transient response.
   
   
3. Use of Structural Element Damping Coefficient GE and conversion into equivalent viscous damping through the use of PARAM W4. No effect on the nonlinear transient response.
   
   
4. The only way left would be to impose directly ALPHA and BETA into the TSTEP card, which doesn't seem to work. The following error is reported in this case: "Incorrect data in field # 3." According to the manual, if I'm not wrong, the field #3 of the TSTEP card is the one devoted to the "Number of time steps of value DT#", which are yet specified in the TSTEP card.

I am running short of ideas, since every effort seems to be ineffective. Even unreasonably high values of damping have no effect on my model. 

I would really appreciate any kind of suggestion and/or comment, which might help me figuring out what's the problem. 
I attach the described models and the related solutions.

I am currently running the 2021 student edition of HyperWorks.