When to account for bending in welded on plate

[vwdevotee]

Hi all,

I'm working on a part and am not sure if the bending stresses should be accounted for in a welded on nut plate and d if needed how that would be done.

I'm welding the attached nut plate to a box tube and a preliminary calculation shows more that adequate strength in the weld [0.707×(2×2.5in+2×3.75in)×0.3125in×68,000psi=188kip]. My question is if and how I accommodate the fact that the nut plate is relatively thin compared to is foot print. If the nut plate were even an inch thick I would assume this is sufficient, by UT at 3/8 I am not confident.

I appreciate any help that can be provided.

 

[MotorCity]

Since you seem to have doubt as to whether or not it is adequate, that is your indicator that you should take a look at it. As for how you go about it, you could do it the super accurate way using FEA or get a close approximation by hand calculations. If this is part of a rocket going to the moon I would use FEA, if this is a DIY house project I would use hand calcs. Without seeing a sketch of the piece and the loading, I cannot provide any meaningful advice on how to go about checking it. It does state a capacity of 25000 lbs, so I assume you know if your load is less than that and also if it is in the same direction as the direction of the load for the suggested plate capacity.