Learning Forum

[munkhunur]

Hello dear,nI am wondering that why a displacement it does not include DOF of rotation options? It means the displacement assumes that all rotations are free automatically or all rotations are ZERO. which one Is that right?nI am looking forward hearing you dear expertsnBest regards nUnur n

[peteroznewman]

A Displacement Boundary Condition only covers the Translational DOF.nSolid elements don't have rotational DOF at the nodes.nShell and Beam elements do have rotational DOF at the nodes. When a Displacement BC is applied to those nodes, the rotational DOF are considered to be Free.nIf you want zero rotation at the nodes then you can use a Fixed Support, which sets all translations and all rotations to be zero.nIn Workbench, there is a Boundary Condition called Fixed Rotations where you can set all or specific rotational DOF to be zero.n

[munkhunur]

Dear Peteroznewman,nThank you always for your kind support. One more question, please? I have done a numerical analysis of the following experimental study, but I found the beam flanges' different deformation behaviors during the numerical analysis than the experimental results. Here, A, B, and C points are constrained. For example, A point C is assumed by fixed support while some directional DOFs are considered in the points A and B relatively given coordinate system. I have tried it by diverse variants of DOF to find accurate results in each point. It demands a lot of patience to finish the calculation time. nFigure-1. General apparatus nFigure-2. Front side buckling behaviors nFigure-3. Back side buckling behaviors nFirstly, I assumed that the rotation Y is constant (0), and other DOF are free in the beam tip. In the point B, Z component and Rotation X are constant because I thought these two vertical columns fully constrained those movements. Unfortunately, the analysis shows me a different shape of deformation behavior than the experimental results. In the analysis shell elements are considered. nFigure-4. Back and front side buckling behaviors. nSecondly, the rotation X is constant (0), and other DOF are free in the beam tip. In the point B, Z component and Rotation X are constant. Again the analysis shows me a different shape of deformation behavior than the experimental results. Here, the deformation behaviors of the first and second variants were similar. nThirdly, the rotation X and Y are constant (0), and other DOF are free in the beam tip. In the point B, Z component and Rotation X are constant. The analysis were terminated and again shows me a different shape of deformation behavior than the experimental results. nHow to know that which DOF of the point A and B acceptable in the numerical analysis? Could you check it out for me please? Please kindly see the attached file.nArrayUnurn