Restart mesh/surface/stress/servo failed

Submitted by Christoph on Fri, 04/21/2017 - 12:49

Hello,

I'm trying to restart a simulation with a servo wall/mesh, unfortunately the servo wall behaves after the restart like a fixed wall. Also a fix_modify integrate start doesn't activate the controller.
According to the documentation a restart should be possible "Furthermore, this fix writes the state of the servo wall to binary restart files so that a simulation can continue correctly".
I tried already to redefine the servo settings after the restart without success. I'm also confused that com needs to be defined after restart - as the servo valve moves during the initial simulation I can't predict it's correct position at restart.

Attached you can find the input script of a test simulation and a diagram which shows the force and position of the servo wall. It should be mentioned that the ground is wiggling in the time interval 0.5-1.3 and 1.8-2.5 s in order to check if the servo wall reacts on the changing contact forces.

Thanks for your support,
Christoph

Edit: I missed to upload the mesh files

ckloss's picture

ckloss | Sun, 04/23/2017 - 12:19

Hi Christoph,

restart and servo walls should work. com has to be defined, but is over-written with the value from the restart file.

Do you use a run command before the servo wall in the simulation doing the restart?

Best wishes
Christoph

Christoph | Mon, 04/24/2017 - 09:48

Hi Christoph,

thanks for you reply.
What do you mean with a run command before the servo wall is doing the restart?
If I run the simulation after the restart (e.g. for one step) before I redefine the mesh I get an error "Mesh (id xxxx): All mesh elements have been lost / left the domain"
In any other combination I have tried so for I either get an error or the servo isn't working/moving.

Shouldn't it work in this way: Redefine the servo with a fix mesh/surface/stress/servo command (defining the mesh file, type, com, ctrlPV, vel_max)
As the servo doesn't work I tried also a fix_modify servo/integrate start command in the next line - without success.
Did I miss something to restart the servo correctly?

Thanks,
Christoph

Zheng Hu | Mon, 10/22/2018 - 12:26

Hi Jack,

I think I have solved this problem. Let's talk about this using E-mail.

Zheng