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Hello

Does anyone have a test/validation case for ShellMITC4 element, e.g. pinching cylinder problem? Since I did not analytical results with that test.

Cheers
G

OK, i found it. It's in T2Vector.h

I saw somewhere in the code this computation is used: double normTS = pow( TStressDev && TStressDev, 0.5); However, when I look into the definition of Vector in matrix/Vector.h, I did not see the operator && defined. Could anyone help to explain the source of this operation? Best Giang

You're right. I made a mistake. For this example I can get convergence only with tol > 1e-08 (test RelativeNormUnbalance 1.0e-8 10 1 2). For the other example, I can get convergence with lower tolerance, but it's with higher thickness. This is still skeptical that that code segment destroyed the ele...

Hi I would like to report that starting from r5141, this commit below destroyed the convergence of ShellMITC4 element: void ShellMITC4::formResidAndTangent( int tang_flag ) { ... //start Yuli Huang (yulihuang@gmail.com) & Xinzheng Lu (luxz@tsinghua.edu.cn) updateBasis( ); // I'm not quite sure w...

You're correct, the ShellDKGQ also works robustly for other tests as well. Nevertheless, in the literature, MITC4 is claimed to be more superior in terms of accuracy. I can help get debug it, if you point me to some material containing explicit algorithm, equations, ...
Best regards

Hello I ran a patch test to check the accuracy of the ShellMITC4 element. The reference of the patch test is according to the example 1 of the paper: Dvorkin & Bathe, A continuum mechanics based four node shell element for general nonlinear analysis. The paper shows that if the element works, th...

I have the same questions as above. I want to use it for soil to replace Drucker-Prager. Does anyone in this forum have experience with this kind of material ?

Hi OpenSees developers, I think there is a bug in function DruckerPragerPlaneStrain::getInitialTangent The current code is: const Matrix& DruckerPragerPlaneStrain::getInitialTangent() { tangent(0,0) = mCep(0,0); tangent(0,1) = mCep(0,1); tangent(0,2) = mCep(0,3); tangent(1,0) = mCep(1,0); tangen...