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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There is one way of how you can implement your project to achieve a result. Our existing structure is deformed without a false ceiling as follows.
We use the existing structure and the drag & drop function as well as copying the elements while holding down the CTRL key for quick modeling. It is important to ensure that the existing pinned connections are displayed correctly. In this example, only one workflow is to be displayed so that the connections between columns and slabs are modeled rigidly. The bottom columns are modeled as nodal supports by using the Column in Z ... function.
The false ceiling should not transfer any loads to the existing continuous columns.
To compare both models, you can evaluate the results by using two substructures modeled in a file.
Materials are required to define surfaces, cross-sections, and solids. The material properties affect the stiffnesses of these objects.
There are 13 material models available if you have a license for the RF‑MAT NL add-on module.
In the case of the abundance of material models, it is necessary to make sure that you assign the corresponding material model to the members and their surfaces/solids.
In the example shown here, surfaces have been generated from a member for a detailed analysis. There is still an unused cross-section defined (marked in blue) and the material is entered for the member cross-section as well as for the surfaces. When editing an existing material to Isotropic Nonlinear Elastic 2D/3D , the 2D/3D material model is also defined for the created member cross-section, which leads to the error message.
When working with members and surfaces / solids, it is recommended to create more than one material.
AnswerIf you use the "Within cuboid - general" integration option, the reason may be incorrectly defined parameters for the application area. The application lengths must be entered as an amount. This is especially important in the negative direction: If you enter the application length as a negative value, this value is subtracted from the positive direction.Example: You want to define an integration area of 1 m for the result beam. For the "Within cuboid - quadratic" option, simply enter an application length of 1 m. In the case of the "Within cuboid - general" option, you have to enter a length of 0.5 m as the amount in both the positive and the negative direction. These lengths are added together and you get a total application area of 1 m.
You can activate the display of the local axis system of members either by right-clicking a member in the member shortcut menu or in Project Navigator - Display.
Member internal forces are displayed with regard to the member axes or the principal axes (FAQ 003291).
You can also find the definition of member internal forces in the online manual.
AnswerGenerally, the resultants in the horizontal direction are obtained if the respective component is not released and is based on a non-double symmetric ground plan.
The positive and the negative direction refers to the axis system of the line release. The forces, such as vz, are related to the object on the original line.
In the following, the definition will be briefly explained by using the example of a release between a wall and a ceiling. If the wall is the released object, the definition of a failure for the lifting load would be as follows:
- Between the floor slab and the wall, the "Fixed if negative vz" nonlinearity should be selected.
- Between the wall and the ceiling above, the "Fixed if positive vz" nonlinearity should be selected.
If the failure is defined incorrectly, you can check it using the determined deformation diagram.
There are three options you can choose from.
Undeformed system: The deformation is related to the initial structure.
Displaced parallel surface: This option is recommended for an elastic support of the surface. The deformation uz,local is related to a virtual reference surface displaced parallely to the undeformed structual system. The displacement vector of the reference surface is as long as the minimal nodal deformation within the surface.
Displaced user-defined reference plane: If the supports of a surface deform very differently, an inclined reference plane for the designed deformation uz,local can be defined. This plane must be defined by three points of the undeformed system. The program determines the deformation of the three definition points, places the reference plane through these displaced points, and then calculates the local deformation uz,local.
After generating a surface from a pipe member, this is no longer connected to the original nodal support. A line support is recommended for the newly created lines at the pipe start, see Figure 01.
Also, the nodal load is no longer connected to the original member. In this case, a crossing of rigid members is recommended for the load introduction, see Figure 02. Thus, the load is transferred to the boundary lines of the surface.
For the first point, the modulus of elasticity of the material is assumed in the material model, so that there is quasi an initial state for the solver to ensure the numerical stability.
If there is no material selected, the first point is not calculated as expected when creating the material model using the Diagram definition type, and cannot be adjusted reasonably.
To avoid this, you have to select the material in advance. Then, you can create the material model as usual, and also adjust the points. The first point can now be adjusted with regard to the stress.
In the case of surfaces with variable thickness, the plane consists of three nodes. The result is a wedge, not a cone, as desired. Therefore, it is recommended to divide the quarter-circular ring into separate uniform surface segments:
- Divide the inner arc line using n intermediate nodes.
- Divide the outer arc line using n intermediate nodes.
- Add individual lines, delete the original surface, and redefine the individual surface segments.
- Add individual lines, divide the original surface using integrated lines.
- Define variable thickness as desired for each individual segment.
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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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