Restitution coefficient - 3D contact

[AB_10950297]

Hi,

I am currently trying to do a simple contact mechanism simulation which is applied on a bouncing ball. I'm using a 3D contact to model the contact between ball and ground. However, I remark that there isn't any options to add restitution coefficient. Can you please tell me where can I add my restitution coefficient in order to make sure the ball bounces back upwards when it touches the ground.

Another question, I found it's weird that the normal force of contact isn't coherent to the position of ball when it's in contact with ground (please view the graphs below). Normally the normal force should achieve a peak when the ball is in contact with the ground, but as you can see in 2nd pic, I only have a constant even at the contact time. Can you please enlighten me where did I do wrongly? 

P/S: the results below is achieved using 2D contact (cams), not 3D contact as mentionned above.

[tbraxton]

Check out this link explaining how coefficient of restitution can be specified. 

About Dynamic Properties (ptc.com)

[AB_10950297]

I can't find where is the motion axis/dynamic properties that have access to coefficient of restitution..

[tbraxton]

See link below:

To Specify Motion Axis Settings (ptc.com)

[AB_10950297]

Okay I've activated the coefficient of restitution but it still gives me the same results. Is it possible to apply the coefficient of restitution on 3D contact, and not at the joints (through dynamic properties on motion axis) ?

[tbraxton]

This model is available in an old post. Check it out and see if it can be used as a guide to build your own version.

A bouncing ball simulation - PTC Community

[AB_10950297]

Hi, 

Thank you for the answers and sharing.

However, I can't open the model due to incompatible version of creo. I've read the pdf in the folder, but it is stated that the person used 2D contact (cam) and not 3D contact. I've tested with 2D contact, and it is proved that I can enter the coefficient of restitution. But with 3D contact, there is no option for coefficient of restitution, which shocks me as it is important for impact simulation. May I know where can I consult to see the equations used behind 3D contact please? 

Thank you in advance. 

[tbraxton]

With the 3D contact you must use "lift off" in the cam connection lift off is in range of (0-1) and is the analogue to coefficient of restitution you are familiar with. Use the PTC help files and tutorials available online. Your question about 3D contact rebound was addressed in the link I provided previously. Here is the link to the help files for how to deal with this using a 3D contact.

About Cam-Follower Connections with Liftoff (ptc.com)

[AB_10950297]

So does it mean that if I want to use 3D contact, I need to make cam connection too? Will they not be redundant? because in my understanding, cam connection represents 2D contact. So if I create both 3D contact and cam connection, it means I will have 2 same contact...Can you please explain me in details, or if I misunderstand anything.

Thank you in advance 🙂

[tbraxton]

Watch this tutorial for an explanation of 3D contact definition which is an example of collision of objects.

PTC Creo 4.0 tutorial: 3D Contacts (youtube.com)