×
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

Question about friction coefficient in SW/Simulation

Question about friction coefficient in SW/Simulation

Question about friction coefficient in SW/Simulation

(OP)
Hi Experts,

Basically I am running a assembly simulation with 4 components
by using SW/Simulation Static. I have several contact sets beside
global contact. I have set the friction coefficient to be 0.35 for all contact sets because it is steel/steel contact with lubrication. System is fully constrainted and simulation is running smooth.

Problem is when I use "list reaction/contact..." in the result
folder to take a closer look at those contact sets. I found for
two contact sets the ratio between friction force and normal force
to be 0.04X and 0.09X, respectively. Why? Shouldn't they to be roughly 0.35? It is a big deal for us, because a part supposed to be self-locking but it is not right now because of lower friction coefficient. Thanks a lot in advance for everyone's comment.

I am using 2011 Solidworks with simulation premium (highest level). Again it is a static study, the most basic one.  

RE: Question about friction coefficient in SW/Simulation

The friction force will equate to the imposed loads in that direction, and nothing to do with the reaction force. F=0.35xR is the point that the joint slips so that condition imposes a limit on the ration of frction to reaction force.  

Tara

RE: Question about friction coefficient in SW/Simulation

I don't understand your problem. What does a transverse reaction being less that what the coefficient of friction times normal force mean? You are running a static analysis when you should be running a non-linear analysis. And, whether you have friction or the part is fixed, if there is nothing pushing transversely you won't see a transverse force.

TOP
CSWP, BSSE
www.engtran.com  www.niswug.org
www.linkedin.com/in/engineeringtransport

"Node news is good news."

RE: Question about friction coefficient in SW/Simulation

(OP)
Thanks for your input, I got it straightened out. I just got deeper understanding about simulation now :D

Here is extremely simple example and a brain teaser for everyone:

  |
  |
   -------
  |       |
  |       |
-------------------

Imagine the above diagram is a block sitting on a flat surface, the friction coefficent is 0.35. Also the block is in contact with a vertical surface on left side surface. There is a force acting on the top surface of block at 10lbf and a horizontal force acting on the right side surface of block at 2lbf. What are reaction force and friction force, respectively? :D
 

RE: Question about friction coefficient in SW/Simulation

(OP)
When I said reaction force, I meant between block and left support.
When I said friction force, I meant between block and bottom flat surface.

The 2lbf force is applied on left side surface of block and pushing the block against the left side surface.  

RE: Question about friction coefficient in SW/Simulation

(OP)
Gee, typo - 2lbf force is applied on RIGHT side of block.  

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