Deactivating A Joint or Changing the Joint Type during Simulation

[struclearner]

Dears,

I appreciate your help/suggestions to achieve/model the following scenario,

How a joint can be deactivated or its type can be changed during a simulation, for example when the rod/piston of a hydraulic cylinder is at the end of its stroke, the joint between rod and cylinder housing is a translational one, after completing its stroke, it actually becomes a fixed joint, when the vehicle steering is done by steering cylinders, the vehicle keeps moving due to driving torque. Is there a way, the translation joint be converted to fixed one, so that piston/rod will not keep moving but the rod and hydraulic cylinder housing will move as a unit.

Thanks for your input.

 

[GregLocock]

Build the thing with both joints connecting the same markers. Deactivate the fixed joint at t=0. When the hydraulic cylinder has reached its limit, stop the sim using a sensor, activate the fixed joint, deactivate the other. Then continue the run.

However I'd have thought you would get a much more satisfactory result by doing whatever the real system does, ie maintaining a high cylinder pressure pushing the piston against an end stop.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[struclearner]

Hello Greg, Thanks a lot for your reply.
I am wondering, all these simulation steps mentioned in your reply, will be accomplished by a Simulation Script. I did use the sensor to stop the simulation when the rod reaches its stroke, but I want to continue to drive the vehicle at the cylinder lock up situation, this is what the real system does.
I also created a contact between rod and cylinder housing, but when the piston comes into contact to cylinder housing, the contact force starts to increase by the parameters defined and this force is in the opposite direction of the applied cylinder pressure which is not the case in reality.
Thanks for your time and help.

 

[GregLocock]

I don't use simulation scripts so I don't know. Seems to me that sorting your contacts out would be a good move.


Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[Armagan Alkan]

Hello struclearner,

In my opinion, you have to define a motion in that translational joint.After that, in motion settings there is a function builder option. You have to use step function in that tab.
Step function will appear like this step(x,x0,h0,x1,h1).You should change the 'x' to time. After this step x0 and x1 values are your joint's moving time.If you set those numbers x0=5 and x1=8 your joint moves between 5-8 seconds.If we need to talk about h0 and h1 values those values must be displacement values for your simulation.

Have a nice day.

Armağan Alkan