Mechanism slider stopping on a shock

[phwarren]

Hello:

I have a mechanism model with a slider going left and right on a rail. I have a shock absorber on either side that is also modeled with mechanism. Here is a picture:

View attachment 4163

How do I set this up in mechanism that when the slider hits the cushion of the shock absorber it pushes the shock in until the shock piston stops (already set in the shock joint axis settings)?? Currently, the slide goes right through the shock piston as in this image:

View attachment 4164

Thanks in advance for the help.






Edited by: phwarren

 

[Kaz Z06]

There are at least two ways to do this. You can make a cam pair and have the two bodies collide as long as their surfaces will always approach each other in a parallel fashion (which it looks like what you have). You can also create a spring and damper between the two colliding surfaces by making a force as a function of another measure (separation distance) and make the spring rate and damping coefficient a function of thise separation distance.

Hope this helps
Edited by: Kaz Z06

 

[mediumsliced]

Wildfire 3.0 has the ability to push objects on collision too. You'll need to enable it via the config.pro option "enable_advance_collision". When enabled, go to Tools > Assembly Settings > Collision Detection Settings > Global/Partial Collision Detection > Push Objects on Collision. HTH.

 

[phwarren]

Unfortunately, we are only on WF2... It sounds like the option I need though!!!

 

[mediumsliced]

Well, it doesn't always work. Perhaps Kaz's solution is the better one for you ATM.

 

[Kaz Z06]

Be careful about using the collision detection capability if you have WF3. This functionality is not meant to replace a well-developed, accurate means to simulate the collision of objects during a dynamic analysis. This functionality was meant to give users the ability to primarily see when/if objects might collide. A result of this abilityalso displays how things may act if they collide. The governing relationships to provide accurate simulation of this situation are far more complex than have been packaged in the collision detection offering WF3 has. The now retired Mechanica Motion product did have a more sophisticated body contact capability in it than the collision detection in WF3.This general contact functionality still has not been duplicated in MDX/MDO. Some of us have already asked PTC to bring back this capability. I'mhoping we'll see this capability again in the next version or two.