Previous in Forum: Steel Design   Next in Forum: How do you decorate a hall?
Close
Close
Close
4 comments
Member

Join Date: Jul 2007
Posts: 5

Allowable Bearing Pressure in Bolted Joints

07/25/2007 12:30 AM

A bolted Joint Join 2-more components together.Bolt is preloaded by Tightening to a specified torque,it produces compressive bearing pressures below Bolt Head.

Request to provide any details if available for this allowable Compressive yield strength/Bearing pressure for the components getting clamped.

If this is not sufficient,parts getting clamped would yield, resulting in preload losses.

Request to pls provide any emperical relation if atall exists between Allowable Bearing Pressure & UTS or Tensile Yield Strength for:(AISC or ASME)

St44.2

16MnCr5

Al 6061T6

Brass

Delrin

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Guru
Engineering Fields - Manufacturing Engineering - New Member Hobbies - Target Shooting - New Member United States - Member - New Member Hobbies - Hunting - New Member

Join Date: Dec 2006
Location: Charlotte, NC USA
Posts: 782
Good Answers: 17
#1

Re: Allowable Bearing Pressure in Bolted Joints

07/26/2007 8:09 AM

Looks like your putting way too much into this. It's really much easier then you express. First, the material of the bolt is explored for the shear proprieties. Then, you check the yield strength of the parts (material). If the shear of the bolt exceeds the yield of the material, your done. The part will fail before the bolt. No more math needed.

OK, now why you ask about pre-loading the bolt? If you don't bring the bolt to elongation point, the bolt will work its self loose over time.

I'm sorry if you wanted seven or eight pages of math, but it's not hard.

__________________
Be careful of what you wish for .....
Register to Reply
Guru
Engineering Fields - Systems Engineering - New Member Hobbies - Model Rocketry - New Member

Join Date: Dec 2006
Location: Long.92E,Lat.26N
Posts: 1336
Good Answers: 14
#2

Re: Allowable Bearing Pressure in Bolted Joints

07/26/2007 11:23 PM

LabyGuy said it all:

You need to Redefine your Problem as Q 1-2-3----

Bolt has to be tightened- surely not to break/damage point.

Newton's 3rd Law! F=p.A so a small pressure on bolted object/s

You want to know that pressure's effect on net Triaxial Pressures?

Look up in the Classics -- Timoshenko,Den Hartog,Mohr,Poisson------

You missed the most important one-What Fit the Bolt Shank has on the Hole walls!

Register to Reply
Anonymous Poster
#3
In reply to #2

Re: Allowable Bearing Pressure in Bolted Joints

07/27/2007 7:54 AM

THERE IS NO BEARING ON BOLTS PERIOD. Bearing implies axial compression and bolts are not compression members they are tension members subjet to sheer forces.

I will do the math for you answer these question

What is the material being bolted?

What is that material supporting (what is the load live and dead keep them seperate)?

Are the bolted members subject to vibration?

What is the diameter of bolt?

What is the Bolt material?

The bolt should be 1/8" smaller then the hole provided in the material being bolted make sure this is the case.

Register to Reply
Guru

Join Date: Jul 2007
Location: Minnesota
Posts: 529
Good Answers: 15
#4
In reply to #3

Re: Allowable Bearing Pressure in Bolted Joints

07/27/2007 8:23 AM

The bolt should be 1/8" smaller then the hole provided in the material being bolted make sure this is the case.

I've always used 1/32 clearance hole for bolts smaller than 1". If I want to eliminate a flat washer I use 1/64 clearance and tighten up the tolerances of the hole locations.

__________________
downhill slide to 112 (damn memor.)
Register to Reply
Register to Reply 4 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Copy to Clipboard

Users who posted comments:

Anonymous Poster (1); ddk (1); Labyguy (1); MUKULMAHANT (1)

Previous in Forum: Steel Design   Next in Forum: How do you decorate a hall?

Advertisement