×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Constraints on an Assembly

Constraints on an Assembly

Constraints on an Assembly

(OP)
Here is an pic of what I am trying to simulate.

http://files.engineering.com/getfile.aspx?folder=f2064b24-cf07-4619-af14-ec3a3e03d2de&file=cam.jpg


I have a simple model of a metal cam rotating on a fixed s/s pin. A metal actuator is being pulled out of the cam causing it to rotate. A fixed plastic plunger is already in the cam stopping the rotation.

What I want to know is what actuator force I need to break the plastic plunger to free up the rotation.

I need to simulate with different materials and see how the different components interacts with each other. So I need to simulate this in the assembly - not seperatley.

to start:
Anyone help me on what type of constraint I should apply to the assembly?

Cheers

RE: Constraints on an Assembly

Break the problem into two parts.

1. What is the torque on the cam at the point it releases the actuator. (Also, at what rotation does this happen?)

2. What is the force on the actuator when it is just before the release position.

Looking at this as an FEA problem:

To solve 1) set your constraints up so that you have a time varying rotational displacement about the pin. Look at the torque reaction as a function of rotational displacement. Once you have that you can move the actuator in SW and determine the angle of release between the cam and actuator and then use the plot of torque to determine the force to solve 2).

To model the plunger/cam interaction, simplify your model to  a plane model with line contact. If you can't do that, then do a pseudo plane model with a thin extrude of the cam profile and the plunger tip profile. I am not sure if Simulation will give you a spring element. If not use Cosmos/M or model a spring by judicious choice of cross section and modulus.

Constrain the plunger tip to move in a straight line. Constrain the end of the spring fixed. Constrain the cam to rotate about the pivot.

Use the soft spring option to get a solution in case you lose contact with the cam.

TOP
CSWP, BSSE
www.engtran.com  www.niswug.org

"Node news is good news."

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources