Allowable Bearing Pressure in Bolted Joints

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.

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!

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.

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.