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BriefFiniteElementNet / BriefFiniteElement.Net

BriefFiniteElementDotNET (BFE.NET) is a library for linear-static Finite Element Method (FEM) analysis of solids and structures in .NET
https://www.bfe-framework.net
GNU Lesser General Public License v3.0
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Update on ConvertBendingStressToCauchyTensor #68

Closed rubsy92 closed 4 years ago

epsi1on commented 4 years ago

in this code

if (lambda > 0) { //top -> add bending stress buf += gst.BendingTensor.ConvertBendingStressToCauchyTensor(z); buf += gst.BendingTensor.ConvertBendingStressToCauchyTensor(thickness, lambda); } else { //bottom -> subtract bending stress buf -= gst.BendingTensor.ConvertBendingStressToCauchyTensor(z); buf -= gst.BendingTensor.ConvertBendingStressToCauchyTensor(thickness, lambda); }

if lambda is negative, then result is wrong, because negativeness of lambda is taken into account in ConvertBendingStressToCauchyTensor but you are considering it again...

epsi1on commented 4 years ago

Hello, I am not sure if am right on above comment. Also please note the FlatShellStressTensor is going to be deprecated...

epsi1on commented 4 years ago

Dear, I did minor changes, can you please do a review? Thanks

rubsy92 commented 4 years ago

Hi, I'm sorry for the delay - I've been on holidays.

Concerning the code: I think that your change on the ConvertBendingStressToCauchyTensor method is not correct... My validation example (hinged plate loaded in bending) yields 0 stress... When I keep the original code I get correct results. I made a new pull request which modifies the code back. The pull request also adds code for the GetLocalInternalStressAt for the q4 elements, as well as a method which allows for Sectionpoints (top/bottom/envelope).