Dear All,

I have a pretty simple problem but I am not sure I can simulate it with Motion (at least, I still did not find the way to).

It's pretty simple, I have a cap that is articulated with a box, the box is fixed to the ground, I have a revolute joint between both. I have a kind of geometry that I have simplified has a spring between the box and the cap.

Basically, when a user push the cap up, he will feel some resistance, after a certain angle, the spring will pass an equilibrum point and will flip the cap over.

Basically, you may find this kind of motion on a shampoo cap. (head & shou***, that's the first brand that comes into my mind)

Now, my problem is too simulate this motion. if I control a rotation to a certain angle, let say that I push the lid untill it is vertical, nothing happens afterwards... which is logical as I don't control it beyond.

I tried to simulate a tab that will push the cap untill the equilibrum point and hope that the spring will force the flip over, but I cannot get a proper contact.

So I finally come to ask help here..

First, can I simulate this kind of motion in Motion?

Thanks

I have a pretty simple problem but I am not sure I can simulate it with Motion (at least, I still did not find the way to).

It's pretty simple, I have a cap that is articulated with a box, the box is fixed to the ground, I have a revolute joint between both. I have a kind of geometry that I have simplified has a spring between the box and the cap.

Basically, when a user push the cap up, he will feel some resistance, after a certain angle, the spring will pass an equilibrum point and will flip the cap over.

Basically, you may find this kind of motion on a shampoo cap. (head & shou***, that's the first brand that comes into my mind)

Now, my problem is too simulate this motion. if I control a rotation to a certain angle, let say that I push the lid untill it is vertical, nothing happens afterwards... which is logical as I don't control it beyond.

I tried to simulate a tab that will push the cap untill the equilibrum point and hope that the spring will force the flip over, but I cannot get a proper contact.

So I finally come to ask help here..

First, can I simulate this kind of motion in Motion?

Thanks

In terms of modeling a cap like a shampoo bottle, are you trying to just show the movement or actually model the real situation. Animating the cap to show how it works is really trivial in just animation/assembly motion. Modeling the true function is a little more advanced.

Plastic caps rely on a press fit somewhere that snaps to a locked position to keep the lid closed (so it requires a certain amount of force to open the cap). Then when you open the lid, you have to overcome the same press fit to pop the cap. To model that behaviour really requires COSMOSWorks to accound for the deformation that occurs when the lid is in the pressed fit stage and flexure due to where your applying force to open the lid. In many cases this may be a nonlinear analysis as relative deformation is large, and if using plastics, they exhibit nonlinear stiffness characteristics.

You cannot really use COSMOSMotion to model the engagement of the lid as it's fundamental assumption is that all bodies are rigid (do not deform).

Let me know if you can discuss more what your goal is and I can comment further.

Cheers,

Ian