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NextFEM AdminKeymaster
Hello,
CatenaryCableElement is already supported for model import and export. Actually, some distributed loads could not be applied to the element, but lumped to equivalent nodal loads. You can test it with version 2.3.EDIT: I forgot to mention: to set a truss as a cable, in Element Properties set CableNL to 1.
NextFEM AdminKeymasterAs told, the program does not have internal automatic meshing. Hence, I simply mean breaking the beam in 2 pieces. Please note that this is required only for single beam model, general structures always have internal (not bounded) nodes.
NextFEM AdminKeymasterThe important thing to do is to have a model with at least an internal node, otherwise the solver tries, as said, to compensate the residuals (especially for rotations) on end nodes.
NextFEM AdminKeymasterDear Alain,
the beam formulation for builtin solver does not account for automatic mesher or pdelta effects correction for a single beam element.
As a result, for pdelta and secondorder effects, you have to consider more than one element for a model. Fortunately, all the model having internal nodes (e.g. structures) does not suffer from this.
Considering the singlebeam model, the moment at middlespan for LC1 is the same for all loadcases, but translated of the initial/ending moment (e.g. 34.186 – 7.629 = 26.55). The unrealistic initial and ending moment is due to the fact that the iterative solver cannot compensate the residual in internal nodes.NextFEM AdminKeymasterDear Luciano,
your post is much appreciated! Thanks also for sharing your python script!NextFEM AdminKeymasterThanks, Luciano. In the next patch you’ll find alignShellXaxis API function.
NextFEM AdminKeymasterDear Luciano,
you obtain “bad” diagram because you don’t have aligned shell local axes. Every force/moment for shells is plotted against local axes for NextFEM Designer.
We currently read the mesh given by Gmsh (not via API, but from GUI only).To solve the problem, align the local axes with Assign / Local axes command.
ps.
we have free internal tria mesher. For regular slab as yours, a structured mesh (made by division) is more suitable. By using a mesh like the one you have, you’re implicitly introducing approximations in results, because finite elements involved (quad) are made to be more accurate when regular (e.g. square).NextFEM AdminKeymasterYou already have such option in Options / mask Solver / Mesh and output preferences box / Beam max output stations
NextFEM AdminKeymasterHello,
the beam output is shown at fixed beam stations (hence not necessarily including maximum), unless you activate “More output stations”.NextFEM AdminKeymasterpsi values can be specified from the Load combination generation mask (Assign / Generate combinations).
NextFEM AdminKeymasterHello,
the principal variable loading case is assumed automatically as the case with the highest combination multiplier amongst all the variable cases. In you model, it is QCatH. This is always conservative, as the greatest factor in combination leads to the higher factor for deflection calculation as per NTC2018 C4.4.7.With kdef=0.8 (SCL=2) you may have (values in m):
Secondaryvariable Neve: (psi0 + psi2 * kdef) * f = 0.0004886155
Permanent G1PP: (1 + kdef) * f = 0.00010358946
Permanent G2Cop: (1 + kdef) * f = 0.0017873568
Principalvariable QCatH: (1 + psi2 * kdef) * f = 0.00053534396
Secondaryvariable Vento_press: (psi0 + psi2 * kdef) * f = 0.000373014for a final sum of 0.00328791972.
It seems the model you sent behaves differently – we’re investigating the issue, please keep your program up to date – if this is the case, we’ll release a patch asap.NextFEM AdminKeymasterHello,
thanks for your interest in NextFEM Designer. Actually, the program can perform implicit dynamic analysis – there’s no specialization for what you ask.NextFEM AdminKeymasterIn the next patch your sample model will be supported (when quad with opposite edges are parallel) – otherwise, mesh area command should be used for complex boundaries.
NextFEM AdminKeymasterThe option is on the material level because otherwise you can assing inconsistent beam stiffnesses. If you need to act to a single DoF (eg. axial or shear only) you can act at a section level (see section properties, Properties tab) by changing A, Avz, Avy, Jy, Jz, and so on.
NextFEM AdminKeymasterHello,
it is only a matter of visualization – in the next patch you’ll see corrected diagrams. 
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