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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Yes, it is possible.
When modeling a spherically curved glass pane, make sure that the surface consists of only four boundary lines.
In RF-GLASS, the option "Activate layered mesh for solids" must be deactivated for double-curved or spherical glass panes.
You can find more information about curved surfaces in RF-GLASS in another FAQ (see link below).
Live load reduction is not considered automatically in RFEM. RFEM and RSTAB are general FEA and framework programs. The program does not understand what is a floor element vs wall element. Only a general plate element is defined. It is not possible for the program to determine the area of a floor for live load reduction.A user must manually consider the reduction by modifying the live load magnitude directly in the load application.
AnswerIn RFEM, the easiest way is to use the "Plane Surfaces" → "Annulus" feature. This allows you to model the reinforcement rings very quickly and easily. Then you can extrude the inner line into a surface, the chimney is already generated. Now, the existing annular surface is copied upwards and the corresponding stiffeners are modeled. You can use the "Rotate" command to distribute the stiffeners over the chimney perimeter.
In principle, it is also possible to perform detailed analysis in RF‑LAMINATE. In the case of a very high shear distortion, for example, it can be reasonable to use orthotropic solids for modeling. The video shows a simple modeling and result evaluation of a layer structure by using solids.
A criterion, as of when is the modeling using solids useful, is the shear correction factor. Further information and other criteria can be found in the following FAQ:
AnswerThe easiest way to consider this is to use the RF-/JOINTS Timber Steel to Timber module. For this purpose, the module decomposes the original connection, and creates a new structural system that considers the flexibility accordingly. This is taken into account separately for load-bearing capacity, suitability for use, and exceptional.
The reason for this warning might be overlapping surfaces, which can occur when for example one solid is modeled onto another, see figure 1.
In order to avoid overlapping surfaces, an opening is required here. After defining that opening, also check if the definition of the solids have to be corrected.
Yes, it makes because this affects the stiffness of the entire system.
When entering a level-floor downstand beam as a ‘Rib’, you will add the stiffness of the defined rectangular cross-section to the area of the line.
For the result beam, however, you have only to define the integration width. The entered rectangular cross-section does not influence the stiffness of the entire system but is only applied as a design cross-section in the add-on modules (e.g. RF-CONCRETE Members).
AnswerA thread cannot be created using a function in the program. In such a case, you have to create this geometrically via nodes and lines. In the program, there is an option to create the windings through trajectory surfaces. However, you have the option to reach your target relatively quickly when using Copy and Rotate.
You can connect a rib member to a line on two surfaces with different thicknesses.
To determine the stiffness or internal forces, the eccentricity of the rectangular cross-section is determined using the mean value of both connected surfaces in RFEM.
For designing in RF-CONCRETE Members, the add-on module determines its cross-section, which is displayed in the input dialog box ‘1.4 Ribs’ of the add-on module.
By clicking the ‘i’ button (see Figure 02), it is possible to open an info dialog box for the generated rib cross-section, where all cross-section properties applied for the design in the module, like the position of the shear center and centroid, etc., can be viewed.
If the ‘Effective Width’ is adjusted in the ‘1.4 Ribs’ dialog box (e.g. to 0.50 m) this has influences on the cross-section applied in RF-CONCRETE Members and its cross-section properties.
However, this does not influence the stiffness or the determination of internal forces in the 3D model in RFEM.
Orthotropic surfaces are non-linear and cannot be designed within the RF-STEEL Surfaces add-on module. It is possible to get a full stress analysis in RFEM for the orthotropic surfaces defined with the orthotropy type "constant thickness" and compared to limiting stresses manually. For all other orthotropy type, the program is not aware of the geometric properties for the surface at every FE mesh point which is needed to calculate stresses. An extensive and detailed FE model would need to be created. See FAQ 2468 for an example of this. Surface types need to be set to "standard" to be designed within the add-on module.
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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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