Results 1 to 4 of 4

Thread: Stress on bolt

  1. #1
    Associate Engineer
    Join Date
    Nov 2014
    Location
    PA, USA
    Posts
    4

    Stress on bolt

    I am trying to determine the max torque before failure on a 5/16” dia bolt (pinned connection). It looks to me the bolt is in single shear at two points. See the attached image. I made an attempt at it. See the other attached image.
    Attached Images Attached Images
    Attached Files Attached Files
    Last edited by mts5143; 01-07-2015 at 12:26 PM.

  2. #2
    Lead Engineer
    Join Date
    Aug 2013
    Location
    Houston TX USA
    Posts
    375
    I suggest you do a quick goggle for "bolt torques". It will give you a number of references and tables for bolt torque limits.

  3. #3
    Technical Fellow jboggs's Avatar
    Join Date
    Mar 2011
    Location
    Myrtle Beach, SC
    Posts
    719
    First, this appears to be homework. Is it?

    It appears from your question that you are talking about the maximum tightening torque on the screw before failure. Most engineers on this forum will assume that's what you are talking about. But your worksheet appears to be a calculation of the maximum torque that can be applied to the 1.25 dia shaft before the 5/16 bolt fails in shear. Your diagram could be read either way. Which is it?

    If in fact you are trying to calculate the maximum torque on the shaft, I have some comments.
    - How do you know the bolt will fail before the shaft or the support bracket do? It might not.
    - Are you sure you used the right information to calculate the cross sectional area?
    - In my opinion you made two other errors in your calculations based on your understanding of the nature of the dynamics of free bodies. But their effect was to cancel each other out.

  4. #4
    Associate Engineer
    Join Date
    Nov 2014
    Location
    PA, USA
    Posts
    4
    This is not homework. It is just some extracurricular work relating to something at work. Yes I am trying to calculate the maximum torque that can be applied to the 1.25 dia shaft before the 5/16 bolt fails in shear. I don't know what will fail first, but my first thought was that the 5/16" bolt would. After that I thought it would be a good idea to try and do the calculation (I like to keep my mind fresh b/c my job doesn't require calcs like this). To begin any problem the first step is the free body diagram. Would you say mine is correct?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •