Bolt Group Max Tension due to Moment
Bolt Group Max Tension due to Moment
(OP)
Hi,
Hopefully simple but I can't find anything on the internet and have no text-books to hand right now.
I need to use a formula to calculate the maximum tension in a bolt group (4 bolts - 2 x 2) due to a moment. The bolts are in a base plate which has a beam protruding from it, and the force is applied laterally to the beam at the top (cantilever beam with end load).
I believe the formula for max tension includes (2A^2 + 2B^2)/B ; where A and B are distances from the edge of the base plate to the first and sedond bolts rows respectively.
Please can someone help me with the correct formula, and also a reference would be great if possible.
Thanks,
Kris
Hopefully simple but I can't find anything on the internet and have no text-books to hand right now.
I need to use a formula to calculate the maximum tension in a bolt group (4 bolts - 2 x 2) due to a moment. The bolts are in a base plate which has a beam protruding from it, and the force is applied laterally to the beam at the top (cantilever beam with end load).
I believe the formula for max tension includes (2A^2 + 2B^2)/B ; where A and B are distances from the edge of the base plate to the first and sedond bolts rows respectively.
Please can someone help me with the correct formula, and also a reference would be great if possible.
Thanks,
Kris





RE: Bolt Group Max Tension due to Moment
You can get more complicated in the analysis by considering bending across the base plate and the point of rotation being at one edge of the base plate. This puts all of the bolts in tension, with different distribution of the load between the two bolt pairs. Now the force couple shifts more toward the bolt group centerline and you can analyze as a two-span beam.
The more accurate way, obviously, is to analyze the plate with FEA, getting vertical reactions for the bolts from the moment applied to the plate.
RE: Bolt Group Max Tension due to Moment
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Scroll down till you see this heading:-
Strength of bolt joints withstanding bending forces
desertfox
RE: Bolt Group Max Tension due to Moment
Another thing, do I add or subtract this tensile force to the bolt pre-tension to get the total force on the bolt?
I'm a bit rusty with these calcs at the moment.
Thanks
Kris
RE: Bolt Group Max Tension due to Moment
RE: Bolt Group Max Tension due to Moment
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