FEM: Stress linearization is wrong (Requires retooling the code)
#20 522 ouverte le 30 mars 2025
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Description
Is there an existing issue for this?
- I have searched the existing issues
Problem description
Stress linearization (Asme VIII Div.2 5-A.4.1.2 or EN-13445) is a calculation on a tensor (all components in local coordinates referring to SCL: hoop, normal and tangential and not global because there's the need to take into account the right components and exclude some of them) and not on a vector (the code instead calculates formulas on an array (YAxis Data of the DataAlongLine that becomes sValues in the formulas)). An equivalent stress cannot be used as input, nor any other quantity taken individually beacuse the purpose is to calculate the tensor of membrane and bending and after that calculate the equivalent stresses of membrane, bending and membrane+bending in order to perfom the verifications. So the inputs must be all the six stress components and x,y,z of the points of line (also to perform the coordinate transformation). The outputs von Mises and Tresca of membrane, bending and membrane+bending and peak. If i'm not misunderstanding the code I suggest freezing the tool until it is rewritten in order to prevent people from using it. I suggest also to doublecheck the code and validate post-processing calculation tools (from several people) before insert it in stable versions of FreeCAD because FEM (and CFD) features are often not like those in CAD where "what i see is what i get". Thank you all.
Full version info
All versions since FEM stress linearization exists.
Subproject(s) affected?
FEM
Anything else?
No response
Code of Conduct
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