Stress Concentrations for Plate with Hole - Applied Bending Moment

[mkenwort]

Greetings all,

I could use some help tracking down a extensive chart showing stress concentrations for plates with a central hole for the case of an applied bending moment.

Additionally, any commentary or tips on the problem of designing a padeye to sustain a force applied at an angle to the plane of the padeye would be helpful. I believe I can simply resolve the applied force into the tensile portion and the bending portion and use the stress concentration charts to find the design stresses?

Also, I have found that 5 times the U.L. is the OSHA requirement for padeyes. Is anyone aware of other relevant regulations on padeye design/safety?

Thanks in advance for any tips and help on these matters,

Mike

 

[arto]

Look in the ASME B30 Series for lifting devices.
If you can tap holes in the product, use swivel hoist rings [the greatest invention!! they always align so there's no "weak " direction

http://www.americandrillbushing.com/ogn_hoi2.htm

]

also, pad eyes usually have no "official" rating, since a lot depends on weld quality/workmanship.

http://www.thecrosbygroup.com/Crosby/

For Stress Concentration Factors, is there anything better than Peterson's book? [probably not]

 

[mkenwort]

thank you for your suggestions

in this case, a swivel hoist is not practical, but i will certainly keep this technology in mind.

additionally, could you please give me the title of Peterson's book? I am unfamiliar with this work.

Thank you,
Mike

 

[TVP]

Peterson's Stress Concentration Factors, 2nd Edition

http://www.wiley.com/cda/product/0,,0471538493,00.html

 

[chicopee]

Instead of making your padeye,why dont you buy commercially made lifting equipment such as those produced by Crosby. There equipment have the appropriate factor of safety complying with OSHA regulations. Dont buy Japanese lifting equipment, there product suck as we found out in one of our job sites. There other US manufacturers that make excellent plate clamps which we used in our heavy structural steel plant to lift up to 20 ton plates. Obviously we had to design our own lifting beams for those jobs. Good Luck

 

[Anthonyr]

It may have more to do with the thickness of the plate and the way it is supported rather than the effect of the stress concentration. I would suggest using Fomrulas for Stress and Strain, 5th ed, by Roark. Table 24, cases 20 thru 23 deal with plates with a central couple. Using one of these, possibly together with another plate case, may give you a good estimation of the nominal stress. Now, Peterson can be used to apply the stress concentration factor to get the maximum stress. For the allowable stress level, I have used one sixth of the ultimate or one fifth of the yield of the plate material when involved in lifting situations.

 

[mkenwort]

Thanks for comments everyone, I believe that with the references mentioned I was able to come up with the appropriate solution.

chicopee:
We use commercial lifting supplies from Crosby, however the steel department at the shipyard manufactures their own padeyes for the riggers.

Thanks,
Mike