I'm looking for established limits or rules of thumb for the validity/accuracy of Euler-Bernoulli beam equations for particularly wide "beams". For example, a simply supported rectangular plate where the breadth(b) is much larger than the height (h) [e.g. b=120 inches, h=1 inch].
Is there a point at which a simply supported beam where b >> h would deflect more like a plate in plate theory rather than a beam in beam theory? If you can, please provide references. Thank you!