How can we update the velocity during an analysis?

[EmadOgail]

Hello friends,
I am modeling a rocking wall subjected to harmonic excitation.
When the rocking wall hits the foundation, an impact happens, and the energy is damped out.
This can be simulated by multiplying the rotational velocity of the wall by a restitution factor (less than one) when the impact happens.

I have tried these commands, but they did not work:
------------------------
set currentVelocity [nodeVel 2 3]

set updatedVelocity [expr {- 0.9 * $currentVelocity}]

set [nodeVel 2 3] $updatedVelocity
-------------------------------------------

My question: is there any way to update the rotational velocity of the wall?

Thanks

[mhscott]

You cannot directly manipulate velocity like that. You should use one or more zero length elements with velocity-proportional materials.

[EmadOgail]

Thanks for your replay,
I tried that but, in this case, the damping from impact is assumed to be continuous; however, in my case it is event-based.
The impact only happens when the rotational angle of the wall approaches zero, therefore, I want to get the velocity when the impact happens and then multiply it with a restitution factor.

Is there any solution?

[EmadOgail]

In other words, how can we apply a velocity or initial velocity to a node such as in free vibration?

[icehockeypest]

I think if want to apply velocity or initial velocity with absolute precision it is not possible but relative velocity can be applied. connections game

[mhscott]

Here's an example with free vibration: https://portwooddigital.com/2021/11/20/ ... onditions/