- Automatic import of structural data and boundary conditions from RSTAB
- Optional consideration of favorable effects due to tension
- Import of axial forces from RSTAB load cases or user-defined specifications for member
- Member-wise output of effective lengths L about weak and strong axis with corresponding effective length factors β
- Results by member listing standardized buckling modes
- Results of critical load factors regarding buckling case for entire structure
- Graphics and animated visualization of buckling modes on the rendered model
- Identification of members free of compression forces
- Optional transfer of the effective lengths to other RSTAB design modules for equivalent member designs according to standards
- Optional export of buckling mode geometry to the RSIMP add-on module in order to create RSTAB imperfections
- Direct data export to MS Excel
RSBUCK | Features
Do you have any questions?
Length: 00:00:26 min
Length: 00:00:44 min
Length: 00:00:38 min
Length: 00:00:21 min
Knowledge Base
Length: 00:00:53 min
Length: 00:00:28 min
When analyzing structural elements susceptible to buckling by using the modules RF‑STABILITY (for RFEM) or RSBUCK (for RSTAB), it might be necessary to activate the internal division of members.
If a member is supported laterally to prevent buckling due to a compressive axial force, it must be ensured that the lateral support is actually able to prevent buckling. Therefore, the aim of this article is to determine the ideal spring stiffness of a lateral support using the Winter model.
This technical article analyzes the effects of the connection stiffness on the determination of internal forces, as well as the design of connections using the example of a two-story, double-spanned steel frame.
With the RF-STABILITY and RSBUCK add-on modules for RFEM and RSTAB, it is possible to perform eigenvalue analyses for member structures in order to determine the effective length factors. The effective length coefficients can then be used for the stability design.
- Automatic import of structural data and boundary conditions from RSTAB
- Optional consideration of favorable effects due to tension
- Import of axial forces from RSTAB load cases or user-defined specifications for member
- Member-wise output of effective lengths L about weak and strong axis with corresponding effective length factors β
- Results by member listing standardized buckling modes
- Results of critical load factors regarding buckling case for entire structure
- Graphics and animated visualization of buckling modes on the rendered model
- Identification of members free of compression forces
- Optional transfer of the effective lengths to other RSTAB design modules for equivalent member designs according to standards
- Optional export of buckling mode geometry to the RSIMP add-on module in order to create RSTAB imperfections
- Direct data export to MS Excel
RSBUCK determines the most unfavorable buckling modes of a structure. It is generally not possible in terms of the calculation method to exclude lower eigenvalues from the analysis and at the same time, to attempt to determine higher eigenvalues. With RSBUCK, you can determine up to the 10,000 lowest eigenvalues of a structural system.
By default, RSBUCK uses the average value of the axial forces occurring on the individual members to calculate the eigenvalues/critical load factors. Optionally, the module can also process the most unfavorable axial force of a member. The determination of buckling modes is performed by an eigenvalue analysis for the entire structure. For this, an iterative equation solver is used.
You only have to specify the following two values:
- the maximum number of iterations
- the break-off limit
Since an exact solution is approximated as close as desired, but never reached, RSBUCK terminates the calculation process after the specified number of iteration steps. In the case of a convergence problem, the break-off limit determines the moment when an approximate solution can be considered as an exact result. Divergence problems have no solution.
RSBUCK is distinguished by easy handling, clear data arrangement, and great user-friendliness. With only a few mouse clicks, you can define the number of buckling modes to be calculated, as well as the load case to be considered.
Structural data and boundary conditions set in the selected load case are imported automatically from RSTAB. Alternatively, you can edit the imported axial forces or enter new values manually. It is also possible to create further RSBUCK cases in order to perform several analyzes each with different boundary conditions.
For a better result display, it is possible to set the units individually in RSBUCK. If the RSTAB internal forces are not available when starting the RSBUCK module, the program calculates the required internal forces automatically before determining the buckling values.
The results of the buckling analysis are displayed in clearly arranged result tables and graphics. Since RSBUCK is fully integrated in RSTAB, you can adjust all results in detail in the printout report according to your individual requirements.
Furthermore, you can easily export all result tables to MS Excel or in a CSV file. A special transfer menu defines all specifications required for the export.
What is the critical load factor and how is it possible to determine it?
How does RF‑STABILITY or RSBUCK determine the buckling load? According to the manual calculation, the respective buckling loads should be about 10% higher.
How is the buckling load determined in RSBUCK if the most unfavorable value is transferred from RSTAB for a non-constant axial force distribution?
Why is it not possible to use result combinations in RF‑STABILITY? It is possible in RSBUCK.
Is it possible to import effective lengths from RF‑STABILITY or RSBUCK in RF‑/TIMBER Pro?
Why are the stiffness modifications not taken into account when determining critical load factors in the RF‑STABILITY add-on module?
Recommended Products for You
RFEM 6 | Main Program RFEM 6
Main Program
The new generation of 3D FEA software is used for the structural analysis of members, surfaces, and solids.
Price of First License
4,170.00 USD
RFEM 6 | Additional Analysis
Add-On
The Structure Stability add-on performs stability analysis of structures. It determines critical load factors and the corresponding stability modes.
Price of First License
1,300.00 USD
RFEM 6 | Additional Analysis
Add-On
The Construction Stages Analysis (CSA) add-on allows for considering the construction process of structures (member, surface, and solid structures) in RFEM.
Price of First License
1,570.00 USD
RFEM 6 | Additional Analysis
Add-On
The Torsional Warping (7 DOF) add-on allows you to consider cross-section warping as an additional degree of freedom when calculating members.
Price of First License
1,480.00 USD
RFEM 6 | Design
Add-On
The Stress-Strain Analysis add-on performs general stress analysis by calculating the existing stresses and comparing them with the limit stresses.
Price of First License
1,210.00 USD
RFEM 6 | Design
Add-On
The Concrete Design add-on allows for various design checks according to international standards. You can design members, surfaces, and columns, as well as perform punching and deformation analyses.
Price of First License
2,550.00 USD
RFEM 6 | Design
Add-On
The Steel Design add-on performs the ultimate and serviceability limit state design checks of steel members according to various standards.
Price of First License
2,550.00 USD
RFEM 6 | Design
Add-On
The Timber Design add-on performs the ultimate, serviceability, and fire resistance limit state design checks of timber members according to various standards.
Price of First License
1,930.00 USD
RFEM 6 | Design
Add-On
The Masonry Design add-on for RFEM allows you to design masonry using the finite element method. It was developed as part of the research project titled DDMaS – Digitizing the Design of Masonry Structures. The material model represents the nonlinear behavior of the brick-mortar combination in the form of macro-modeling.
Price of First License
1,660.00 USD
RFEM 6 | Design
Add-On
The Aluminum Design add-on performs the ultimate and serviceability limit state design checks of aluminum members according to various standards.
Price of First License
1,750.00 USD
RFEM 6 | Joints
.png?mw=600&hash=49b6a289915d28aa461360f7308b092631b1446e)
Add-On
The Steel Joints add-on for RFEM allows you to analyze steel connections using an FE model. The FE model is generated automatically in the background and can be controlled via the simple and familiar input of components.
Price of First License
2,110.00 USD
RSTAB 9 | Main Program RSTAB 9
Main Program
The modern 3D structural analysis and design program is suitable for the structural and dynamic analysis of beam structures as well as the design of concrete, steel, timber, and other materials.
Price of First License
2,910.00 USD
RSTAB 9 | Additional Analysis
Add-On
The Structure Stability add-on performs the stability analysis of structures. It determines critical load factors and the corresponding stability modes.
Price of First License
1,300.00 USD
RSTAB 9 | Additional Analysis
Add-On
The Torsional Warping (7 DOF) add-on allows for considering cross-section warping as an additional degree of freedom when calculating members.
Price of First License
1,480.00 USD
RSTAB 9 | Design
Add-On
The Stress-Strain Analysis add-on performs a general stress analysis by calculating the existing stresses and comparing them to the limit stresses.
Price of First License
1,120.00 USD
RSTAB 9 | Design
Add-On
Concrete Design add-on allows for various design checks of members and columns according to international standards.
Price of First License
2,550.00 USD
RSTAB 9 | Design
Add-On
The Steel Design add-on performs the ultimate and serviceability limit state design checks of steel members according to various standards.
Price of First License
2,550.00 USD
RSTAB 9 | Design
Add-On
The Timber Design add-on performs the ultimate, serviceability, and fire resistance limit state design checks of timber members according to various standards.
Price of First License
1,930.00 USD
RSTAB 9 | Design
Add-On
The Aluminum Design add-on performs the ultimate and serviceability limit state design checks of aluminum members according to various standards.
Price of First License
1,750.00 USD