Linear Elements vs. Quadratic Elements Comparison (Just for Information)

VMH

Same models and boundary conditions except for one with linear elements (without midside nodes) and another with quadratic elements (with midside nodes).

Victor

Interesting comparison. I'm surprised the results are so similar! Since these are solid elements, it's to be expected that the linear hex8 model doesn't deflect as far because those elements are unphysically too stiff in bending. You would usually need several layers so that no individual element experiences much bending.

I notice a possible inconsistency in the constraints - they don't appear to be applied to the midside nodes and that may influence the overall stiffness. If you apply them to faces instead of nodes, then they'll be maintained properly when you change element shapes.

VMH

Victor,

Thank you for your comments.

I simplified the models and rerun the comparison (see attached images).