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Frequently Asked Questions (FAQ)
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AnswerIn addition to geometry input errors, the cause is usually the different calculation principles of both modules.The design of an end plate joint with the RF-/JOINTS Steel - DSTV add-on module is carried out by comparing the saved ultimate load capacities with the design internal forces. The underlying load capacities are taken from the current DSTV guidelines.When using the RF-/JOINTS Steel - Rigid add-on module, the capacities of the connections are calculated according to DIN EN 1993-1-8 by means of the component method. Thus the results can be directly influenced by the used settings.By default, an elastic distribution of bolt forces is used as a basis. By selecting a plastic force distribution in the connection, you can activate additional load capacities. They are already included in the limit load capacities according to the DSTV-guideline.Therefore, to obtain comparable results between both add-on modules, a plastic distribution of forces must be applied for the calculation. In addition, it is important to ensure a correct modeling of the connection geometry.
AnswerIn the current standards, fasteners or connections are always designed in one plane only. The reason for this is that the designs for shear etc. can only be analyzed in the 2D plane. The hole design, for example, is not possible for a failure from the plane.Since internal forces in v y and v z can always occur in a three-dimensional calculation, it has been proven in practice to allow a small proportion of internal forces in secondary direction and not fully utilize the connection. However, if the ratio of shear force in secondary direction is too high, a detailed analysis with an FE simulation might be necessary.
The easiest way to find the internal forces at these nodes is to print the pictures of members into the printout report.
If this solution is not an option, you can also find the values in the result table 4.1 in the printout report. Since the extreme values are only activated by default, it is still necessary to activate nodal values in the selection.
It is usually not reasonable to include the internal forces of all member in the printout report. Therefore, you can only select the members that are relevant to you.
RF-JOINTS performs an idealized design of a steel connection according to the standard, which cannot be easily compared with an exact FE calculation.
Thus, the following conditions must be met:
- Consideration or exclusion of friction/compression/tension within the contact solid (tab 'Solid') as well as for the bolts modelled subsequently
- Consideration of internal forces and deformations within the subsequently modelled end plates or similar, which causes redistribution of bolt forces in the FE calculation (in contrast to the idealized design in RF‑JOINTS)
This can be corrected by rigid connection objects, for example (an end plate as a rigid surface).
- Uniform load introduction into the FE model, for example, by using rigid members or rigid surfaces as described in the article 'FEM Modeling Approaches of Rigid Connections'
In the RF‑/JOINTS add-on module, you can export result graphics as DXF files. The corresponding button is below the graphic in Window 4.1 (see Figure 01).
After you click the button, the Windows dialog box 'Save as' appears where you can enter the name and the file path of the DXF file.
RF-/JOINTS is divided into several joint groups. Each of these joint groups requires a separate licence key. If RF-/JOINTS detects a key, the joint group is marked with a green circle (see Figure).
In your case, you have probably selected a joint group that is not licenced. Therefore, please set the joint group that you have purchased. The message about the demo version should then disappear.
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