×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*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.

# Bearing Stress3

## Bearing Stress

(OP)
Can someone help me out or point me to a good web resource?

I need to calculate bearing stress and, frankly, I don't think this was covered in school.

Simply, imagine a piece of U-Channel with the open end facing down.  Drill a hole through one side and out the other.  Put a bolt through it and hang something heavy from the bolt.

I know how to claculate stress if I was simply pulling on a flat plate with a hole in the middle (P/A with some stress concentration factor for the hole), but what about deformation of the hole if the load is ON the hole (as stated above).

Any help will be greatly appreciated.

-Barry

### RE: Bearing Stress

(OP)
OK....I think I found something.  Feel free to comment on applications.

A(bearing) = Diamter x Thickness
Sigma (bearing) = F/A
N(bearing) = Sy/Sigma

A(tearout) = length x thickness
tau = F/A
N(tearout) = 0.577xSy/tau

### RE: Bearing Stress

Your bearing stress area would be
the area of the washer od
minus the area of the hole diameter.
This is a surface stress.

### RE: Bearing Stress

3
Your calculations for bearing stress are accepted as an initial starting point.  The tearout area should be multiplied by two because you are creating two surfaces.  You can find the analysis technique in section 12.2 of Handbook of Bolts and Bolted Joints edited by Bickford and Nassar.  You also can find information on this subject in Guide to Design Criteria for Bolted and Riveted Joints by Kulak, Fisher, and Struik available for free here:

http://www.boltcouncil.org/guide1.htm

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

### RE: Bearing Stress

diamondjim's answer is for bearing stress (more appropriately called surface pressure) due to the fastener's preload.  It is unrelated to your question.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

### RE: Bearing Stress

(OP)
Thanks.  DiamondJim, my load would be perpendicular to the axis of the bolt.

CoryPad, I don't really understand the reasoning behind tearout area.  Why do I multiply it by 2?  .........wait, I'm looking at the example in the book now.  They multiply by 4 for a situation such as this.  In other words, thickness is the thickness of the material that each of the 2 holes is in and there are 4 surfaces total that these 2 holes are on.

I get it.  Thanks for checking my work!

### RE: Bearing Stress

you are welcome

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

#### 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.

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!