Stress Concentration of Hole through HSS

[Darken99]

Does anyone have any reference material on how to determine the stress concentration of a hole in HSS tube. To give you an idea what I am working with, I have an HSS tube fixed at both ends with a 7 ton Eye bolt fastened through a hole in the center of the HSS tube.

Any information would be great.

Thanks.

 

[gurmeet2003]

Darken99,

Have you checked Peterson's book?

Gurmeet

 

[Darken99]

gurmeet2003,

No I have not checked it. I will see if I can track it down. Most books I have checked have stress concentration for rods and plates but no structural steel.

 

[rb1957]

i don't think the material will change the stress concentration significantly. what changes is how the material can accept the stress concentration (ie fatigue life).

does the eye-bolt attach to the tube ? or does it pass thru the tube and is secured by a nut ?? (i'm picturing the tube being horizontal, like a beam, and the eye-bolt applies a vertical load).

 

[Darken99]

rb1957,

The eye bolt passes through a hole drilled through the HSS tube which is fastened with a nut from the top. The eye-bolt is supporting a vertical load. I also don't believe this hole will have a significant stress concentration but I need to justify my assumption.

 

[EdR]

Assuming I understand the problem I don't believe that (see) there is any stress concentration from this setup....You should check for local deflection of the top of the section, contact stresses, bending stresses, and vertical shear stress in the region outside of the local area (this is the same type of failure that occured in the Hyatt in Kansas City)

Ed.R.

 

[rb1957]

yes, i agree that the area lost due to the hole is probably insignificant, and that overall the effect of the hole is negligible. you can calculate the bending stress in the tube (ignoring the hole) then apply the standard Kt for a hole (=3). you will almost certainly get local yielding but this is normally acceptable, depends on repeated loading. also, how well distributed is the load interface with the nut; again a small point, but there may be local yielding (as the nut "settles" into the tube) but shouldn't be a big deal.

 

[BobM3]

The enclosed has stress concentrations:

http://www.fatiguecalculator.com/finders/findkt.htm

What is HSS?

 

[rb1957]

HighStrengthSteel

 

[Darken99]

Lots of stress concentration factors and documentation for flat and round bar but not too much for structural steel.

 

[rb1957]

stress concentration is dependent on geometry, not material.

 

[Skicat]

HSS = hollow structural section