I am confused by the results of the analysis of a thin plate under its own weight.
Plate 300х29cm with thickness 0.1cm
In liner static i have inadequate resalts, total translation 464.5 cm
In nonliner static its ok, total translation 1.118 cm
I understand that non-linear analysis typically reduces displacements, but not as much)
Please explain why I can not consider this task in a linear formulation and why this happens?
Solved! Go to Solution.
You are suffering stiffening effect, in linear static is totally ignored, but in nonlinear analysis this is detected as a geometric nonlinearity, please post your model and we will take a look to it, OK?.
Post the model again, not available!.
Not success, I don't see the file, make sure to ZIP the FEMAP file, also check that is set public, not private, for any reason your file do not appear visible to me ready to download.
You are considering an extreme case, then the big differences found:
This nonlinear analysis consider the membrane forces of the shell elements, when the linear static analysis simply ignore at all. The plate is under dead gravity load, then is working in tension, so here we are the stress stiffening effect.
The term "stress stiffening effect" refers to a coupling between membrane stress and lateral displacements associated with bending. The bending stiffness of a beam, arc, plate or shell is increased by tensile membrane stress, and decreased by compressive membrane stress, ie, stress softening effect, ie, buckling.
Stress stiffening effect is negligible for massive bodies, but the example here is a extremely thin-walled plate, then the problem is extremely non-linear by geometry, understood?.
In summary, double-check your results always running both linear & nonlinear analysis, OK?.