I simulated a cylinder of length 75 and radius 2 in Abaqus using shell elements (S4R) for the cylindrical shell and solid elements (C3D10) for flanges. The connection between flanges and cylinder is done via shell-to-solid constraint. The thickness of the cylinder is varying from 0.03 at bottom to 0.013 at top. At top a concentrated lateral force of 100 is applied. Bottom edge is fixed.
I wanted to validate my results by comparing it with a beam. Thus, a beam is created of length 75. The thickness again is varying from 0.03 to 0.013. Same BC and load condtions are applied here. No influence of flanges here, just a straight beam divided into parts with different thickness. B31 elements are used.
A linear static analysis is followed. While displacements are close, I noticed something stange regarding Von Mises stresses. The location of S.Mises at both models is different. In cylindrical shell max Mises is at boundary while in beam model is above boundary. Any idea why is this happening? I was expecting also S.Mises for beam to be at boundary
The jump of beam thickness could cause this location of max Mises.
Victor J. Аdlucky cylindrical shell also has varying thickness( same as beam) but there is no such jump?
You think is better to compare the displacements and not stresses?
In my opinion, these two so different models give quite close results for max stresses.
Victor J. Аdlucky so the calibration of the shell model is quite correct as I understand, right?
In the shell model, these can be local stress surges ("edge effect"). If the mesh is refined at this point, these stresses will increase. Flexural stresses are added to the membrane stresses. With such a small thickness, they should be significant.
(Why are the maximum stresses in one model at the top of the picture, in the other at the bottom? Models reversed?)
Vitalii Myntiuk Both models have one end fixed. In beam model max mises appears above fixed end( I didn't expect that) and in the shell model with flanges made of solids max mises at bottom.
Spyros Arvanitis If there is no greater distortion of the section in the shell, then the result is contradictory. More information is needed.
The beam model should perform well with this elongation.
Victor J. Аdlucky Of course. Both beam and shell(with flanges) model are uploaded.
Spyros Arvanitis As was expected, there is the highest jump of wall thickness (0.0045) at the node with max Mises in beam model. Note that external radius of the beam cross-section remains constant (2) while the wall thickness decreases. Therefore, integration points become closer to external boundary of cross-section, and max axial stress increases even though the bending moment decreases linearly along the beam.
Victor J. Аdlucky I see. However, the two models give very similar results
Spyros Arvanitis Yes, both models give very similar results. In my opinion, the reason why shell model does not produce max Mises at the intermediate node (as in beam model) is that part of integration points for shell elements lie on the outer shell surface where max Mises is gained (in contrast to beam elements with pipe section).
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