NX10.0 Motion Simulation Curve on Curve Constraints

[lewm5]

Hi all,



I am currently designing an over head camshaft with the relevant rocker arms. I have used curve on curve constraint within motion simulation to follow the profile of the camshaft once an acceleration has been applied - this works correct in animation. however, once I try to apply two rocker arms and another curve on curve constraint, the solver locks up with the error message "RecurDyn Solver Lockup" and

Error No.1108506 <Simulation> : Solver processing failed. (refer to the *.msg file)



Has anyone came across this before or has any knowledge on how to correct it?

Any guidance would be appreciated



Thanks!

 

[SS88]

My first advice is to double-check the simulation because 100% of the recurdyn solver lockups that have happened to me have been because of my mistakes

I have done something similar (link below) by using the curve on curve constraints and I'd remember having some problems related to the initial positions of the geometries. There is the .prt and .sim in the link also so hopefully you can find something useful from it at least.

In this example I used Spring connectors between valve and head, 2D contact between rocker arm and valve, Curve On Curve to make the pushrod follow the camshaft lobe. So it's quite the same as what you're doing. I also had to use Damper to soften the valve spring movement to keep the simulation stable.

http://grabcad.com/library/hemi-head-sketch-motion-simulation-1

Let us know if you made progress with it and found the solution.

 

[lewm5]

Hi SS88,

Thanks for your reply!

I will look into this and let you know - many thanks for your guidance.

 

[lewm5]

I believe my problem may have been slightly different to yours. I can get the curve on curve constraints for both the valve to rocker arm connection and rocker arm to cam.
It is when I try to add a second rocker arm to the cam that the solver locks up - did you have any problems when placing a second rocker to another camshaft lobe?

Thanks.

 

[SS88]

I don't remember having any problems with the second constraint. Is it possible that you could share the model or at least the necessary objects of it?

 

[lewm5]

yes that would not be a problem. What would be the easiest way to do this - through grabcad?

 

[Toost]

You can zip the necessary files and upload them here if you like.
Note though that the files will remain here..

Regards,
Tomas

 

[SS88]

If I try to open the motion_1p.sim NX is trying to locate pushrod2.prt which is the assembly file used in the motion simulation. That should be included in the files too. Same happens with the motion_1p1.sim.

Can you include that file too because else I can't open the simulation.

 

[lewm5]

Hi Samu,

Thanks for your time, I think I have found a solution!

I believe the profile of the curve intersection with the straight line was too severe, this may have resulted in the simulation not being able to run. I have changed the profile and used a point on surface and it seems to run ok!

many thanks for your time and help.

Kind regards

 

[SS88]

Good that the problem got solved! Seems that the solver lockup reason was what I presumed