Dlubal RFEM 5 & RSTAB 8 – Standards for Classification and Combinations

Dlubal RFEM 5 & RSTAB 8 - Standards for Classification and Combinations

Dlubal RFEM 5 & RSTAB 8 – Standards for Classification and Combinations

By Robert Vogl, Dlubal Software

In RFEM and RSTAB, it is possible to combine load cases with the correct partial safety factors automatically.

The current standards are preset in the list by default. If you need an “old” standard, use the [Filter] button to show the previous versions.

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Dlubal RFEM 5 & RSTAB 8 – Critical Load Factor of Tapered Steel Frame 3: FE Model and RF-STABILITY

Dlubal RFEM 5 & RSTAB 8 - Critical Load Factor of Tapered Steel Frame 3: FE Model and RF-STABILITY

Dlubal RFEM 5 & RSTAB 8 – Critical Load Factor of Tapered Steel Frame 3: FE Model and RF-STABILITY

By Frank Sonntag, Dlubal Software

The following post verifies the determined mode shapes or critical load factors of the previous beam structures using an FE model in RFEM (surface elements) and RF-STABILITY.

You can quickly create such model in RFEM due to effective modeling tools (“Generate Surfaces from Members” here) and the well-arranged graphical user interface.

In RF-STABILITY, critical load factors and the corresponding stability modes can be determined. For this, you can use linear eigenvalue solver or nonlinear stability analysis.

In our example, the linear eigenvalue solver (Lanczos method) determines the critical load factor of 2.26, which corresponds to the previous models of the structure.

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Dlubal RFEM 5 & RSTAB 8 – Verification Example: Equivalent Loads

Dlubal RFEM 5 & RSTAB 8 - Verification Example: Equivalent Loads

Dlubal RFEM 5 & RSTAB 8 – Verification Example: Equivalent Loads

By Gerlind Schubert, Dlubal Software

On the Dlubal website there is a new verification example about equivalent loads available (Example 105).

In this example the natural frequencies, the effective modal masses, and the equivalent loads of a cantilver beam with five mass points are analytically calculated. The equivalent loads that are determined with RF-/DYNAM Pro – Equivalent Loads are compared with this analytical solution.

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Dlubal RFEM 5 & RSTAB 8 – Quick Info About Elements

Dlubal RFEM 5 & RSTAB 8 - Quick Info About Elements

Dlubal RFEM 5 & RSTAB 8 – Quick Info About Elements

By Gerhard Rehm, Dlubal Software

You may already know the “Center of Gravity and Info” function, which can be accessed by using the shortcut menu of any element. If you want to display this information on several elements consecutively, you have to close the dialog box and open the shortcut menu of the next element over and over again.

For this, it is easier to use the “Info About Object” function which is available in the toolbar (see the picture). Once you start the function, the corresponding dialog box displays the information of any element as the cursor runs over it. It does not matter whether it is a member, a surface, or a solid; the program detects the element type automatically and displays the respective information.

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Dlubal RFEM 5 – Form-Finding Stage in RF-FORM-FINDING

Dlubal RFEM 5 - Form-Finding Stage in RF-FORM-FINDING

Dlubal RFEM 5 – Form-Finding Stage in RF-FORM-FINDING

By Andreas Niemeier, Dlubal Software

During the form-finding process, the elasticity of a substructure is also taken into account when searching for the equilibrium state. You can also consider large deflections of supporting trusses or pure bending deformation of the edge beams when determining the membrane shape.

If no additional deflection of membrane supports appears, the respective edges can be defined with a support including the nonlinearity of “Form-finding stage only”. Thus, these supports are effective in the form-finding process only. In this step, all relevant points and lines are supported in the selected direction. These settings do not apply to any further calculations using the new membrane shape.

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Dlubal RFEM 5 – Application Possibilities of Average Regions

Dlubal RFEM 5 - Application Possibilities of Average Regions

Dlubal RFEM 5 – Application Possibilities of Average Regions

By Alexander Meierhofer, Dlubal Software

In RFEM, it is possible to define areas where the internal forces in surfaces are not displayed with the real distribution from FE calculation but as mean values. You can use various settings for averaging the internal forces. There are three possible application areas of the “Average Region” function:

Application area 1: Spreading internal forces in surfaces over their effectiveness, for example the internal forces in surfaces should be distributed to a one-metre plate strip.

Application area 2: Spreading internal forces in surfaces longitudinally over their effectiveness, for example smoothing a supporting moment using a support.

Application area 3: Setting internal forces in surfaces over the region to zero; in this way, it is possible to hide singularity points or moments exceeding design moment within a support, for example.

Default average region settings apply only to the finite elements which are located completely within the defined region.

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Dlubal RFEM 5 & RSTAB 8 – Displaying Spring Members

Dlubal RFEM 5 & RSTAB 8 - Displaying Spring Members

Dlubal RFEM 5 & RSTAB 8 – Displaying Spring Members

By Sandy Matula, Dlubal Software

You can display spring members in the Display navigator. A spring member is displayed as a helix by default. Clear the “Spring Members” check box to display them as normal lines.

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Dlubal RFEM 5 & RSTAB 8 – Effective Lengths for Lateral-Torsional Buckling in RF-/TIMBER Pro

Dlubal RFEM 5 & RSTAB 8 - Effective Lengths for Lateral-Torsional Buckling in RF-/TIMBER Pro

Dlubal RFEM 5 & RSTAB 8 – Effective Lengths for Lateral-Torsional Buckling in RF-/TIMBER Pro

By Bastian Kuhn, Dlubal Software

In RF-/TIMBER Pro, it is also possible to define effective length for lateral-torsional buckling. The effective length for lateral-torsional buckling is then calculated according to EN 1995-1-1, Table 6.1. This option is useful especially for nonuniform load introduction.

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Dlubal RFEM 5 & RSTAB 8 – Approach 2* According to EN 1997-1 in RF-/FOUNDATION Pro

Dlubal RFEM 5 & RSTAB 8 - Approach 2* According to EN 1997-1 in RF-/FOUNDATION Pro

Dlubal RFEM 5 & RSTAB 8 – Approach 2* According to EN 1997-1 in RF-/FOUNDATION Pro

By Paul Kieloch, Dlubal Software

Due to RF-/FOUNDATION Pro, it is possible to perform the geotechnical design of single foundation according to EN 1997-1 in RFEM 5 or RSTAB 8. Depending on the National Annex preset in the add-module, you can determine bearing resistance using Approach 2 or 3 in compliance with EN 1997-1 up to the Version x.04.0108.

As of the program versions x.05.0018, there is an additional Approach 2* for the determination of bearing resistance.

The essential difference between Approach 2 and Approach 2* is that the determination of bearing resistance according to Approach 2* applies characteristic values of loading. This has a favorable influence on the eccentricity and load inclination used in the bearing resistance equation.

You can select the approach for the bearing resistance determination under Parameters of National Annex (see the picture). The availability of the individual approaches depends on the National Annex selected in Window 1.1.

The program automatically determines the characteristic loads as initial values for each load combination entered in Window 1.4 under Structural (STR) and Geotechnical (GEO) to determine the bearing resistance using Approach 2*.

In summary, you can use Approach 2* especially for significantly eccentric loading situations to achieve efficient foundation dimensions if the ground failure design is relevant for the foundation dimensions.

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Dlubal RFEM 5 & RSTAB 8 – Adjusting Buckling Curve of Cross-Section in RF-/STEEL EC3

Dlubal RFEM 5 & RSTAB 8 - Adjusting Buckling Curve of Cross-Section in RF-/STEEL EC3

Dlubal RFEM 5 & RSTAB 8 – Adjusting Buckling Curve of Cross-Section in RF-/STEEL EC3

By Wieland Götzler, Dlubal Software

You can adjust the buckling curve of a cross-section in RF-/STEEL EC3, if necessary. This can be done in the “1.3 Cross-Sections” window.

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