×
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

Correct contact characteristics for friction on a bolt head

Correct contact characteristics for friction on a bolt head

Correct contact characteristics for friction on a bolt head

(OP)
OK all, I have an interesting one for you.  

I have a set of bolts threaded into a cylindrical bulkhead.  Shown in figure 1, they thread into the bolthead and ultimately make contact with an outer ring face.  

A axial tensile load is applied to the assembly, and through constraints, is directed through the ring-to-bolthead contact.  

I've set this contact for a frictional pure penalty, adjust to touch, coefficient of 0.1 with an acceptably small pinball radius.

Figures 2 and 3 show the resulting stresses

My question is...  The stress concentration on the bolt head seems realistic, although the peak value is awfully high.  Can I interpret this to mean that the bolt heads will be dented at the point of contact, and possibly seized?  Also, how do I interpret the frictional stress on this bolt head in the form of an approximate equation?  

Can I resolve the 2500lbf axial load into a 625lbf load per bolt, then resolve this into 45 degrees (the angle of contact) for a tangential load on the bolt head, and then finally divide that load by the element area?  Doing this resulted in around 50,000psi, as opposed to 41000psi in the model.  Is that acceptable?  





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