In addition to our technical support (e.g. via chat), you’ll find resources on our website that may help you with your design using Dlubal Software.
Frequently Asked Questions (FAQ)
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AnswerSimilarly to surfaces, there are various smoothing options for displaying the results of support reactions. For a nonlinear support, you should always select the actual distribution to display the results.
Most likely, the error is in the selection of the cross-section:
For steel design, a thin-walled flat bar cross-section should be selected instead of a rectangular solid cross-section, see Figure 01.
The reason for the high shear stress of a solid cross-section is caused by the existing stress points of the cross-section or by the corresponding thickness of this stress point.
In the case of a thin-walled flat bar cross-section, there are four stress points at the corner points of the cross-section with the corresponding thickness t = 10 mm, see Figure 02.
For a solid cross-section, however, there is another stress point in the center, where the maximum of height h or width b is assumed as the thickness t for this cross-section type. In this case, the width b is 200 mm, see Figure 03.
This results in a small torsional section modulus Wt and the correspondingly high shear stress.
The solution is, as described above, to select a flat bar in the main program.
There is very likely an inaccuracy in the modeling, which has to be checked as follows:
- Set the view in the member direction, then zoom in.
- Select all existing nodes that should lie on the same line: If the respective coordinates in the transverse direction do not correspond to the member axis, the corresponding field of the coordinate is empty and there is a deviation.
AnswerIn the case of significant deviations, the problem may be caused by the applied bending theory (Mindlin or Kirchhoff).For this, see FAQ Mindlin Kirchhof.
AnswerThis kind of result may occur if the limit internal forces of the cross-section cannot be determined. In most cases, the problem lies in a wrongly defined cross-section or in the selection of an unsupported cross-section. Please check if you have selected the cross-section allowed for the aluminum structure in the add-on module. These include the rolled cross-sections and parametric thin-walled cross-sections.The cross-section HK 120/40/5/5/5/5 shown in Figure 01 is not a valid cross-section as it has been selected from the area of solid cross-sections (concrete components).
In this case, it is necessary to change the cross-section to TO 120/40/5/5/5/5.In the case of the design in RF‑/ALUMINUM, please note that you have to select the material which also involves thicknesses used for the cross-sections. A material that is only allowed up to t=3 mm cannot be used for a cross-section with t=5 mm.
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Wind Simulation & Wind Load Generation
With the stand-alone program RWIND Simulation, wind flows around simple or complex structures can be simulated by means of a digital wind tunnel.
The generated wind loads acting on these objects can be imported to RFEM or RSTAB.
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