Structure Stability for RFEM 6 / RSTAB 9

Product Description

  • Add-on Module of Category "Other"

Add-on for Stability Analysis According to Eigenvalue Method and Incremental Method


Receive information including news, useful tips, scheduled events, special offers, and vouchers on a regular basis.

A Perfect Combination

"The RFEM add-on module RF-STABILITY is a perfect combination with RWIND Simulation. Using RF-STABILITY, I can perform a buckling analysis to get accurate effective lengths. Using RWIND Simulation, I can get accurate wind loads. For unusually shaped structures, it would be a wild guess if calculating wind loads from the standard code... either not conservative or too conservative. My client is happy with the results and impressed!"

Do you need to carry out a stability analysis? With the '''Structure Stability''' add-on, you can do it with minimum effort. The program determines critical load factors and the corresponding stability modes.



  • Calculation of models consisting of member, shell, and solid elements
  • Non-linear stability analysis
  • Optional consideration of axial forces from initial prestress
  • Four equation solvers for effective calculation of various structural models
  • Optional consideration of stiffness modifications in RFEM/RSTAB
  • Determination of stability mode greater than the user-defined load increment factor (Shift method)
  • Optional determination of the mode shapes of unstable models (to identify the cause of instability)
  • Visualization of stability mode
  • Basis for determining imperfection


If there is a load case or load combination in the program, the stability calculation is activated. You can define another load case in order to consider initial prestress, for example.

For this, you need to specify whether to perform a linear or nonlinear analysis. Depending on the case of application, you can select a direct calculation method, such as the Lanczos method or the ICG iteration method. Members not integrated in surfaces are usually displayed as member elements with two FE nodes. With such elements, the program cannot determine the local buckling of single members. That's why you have the option to divide members automatically.



You can select several methods that are available for the eigenvalue analysis:

  • Direct Methods
    • The direct methods (Lanczos [RFEM], roots of characteristic polynomial [RFEM], subspace iteration method [RFEM/RSTAB], and shifted inverse iteration [RSTAB]) are suitable for small to medium-sized models. You should only use these fast solver methods if your computer has a larger amount of memory (RAM).
  • ICG Iteration Method (Incomplete Conjugate Gradient [RFEM])
    • In contrast, this method only requires a small amount of memory. Eigenvalues are determined one after the other. It can be used to calculate large structural systems with few eigenvalues.

Use the Structure Stability add-on to perform a nonlinear stability analysis using the incremental method. This analysis delivers close-to-reality results also for nonlinear structures. The critical load factor is determined by gradually increasing the loads of the underlying load case until the instability is reached. The load increment takes into account nonlinearities such as failing members, supports and foundations, and material nonlinearities. After increasing the load, you can optionally perform a linear stability analysis on the last stable state in order to determine the stability mode.



As the first results, the program presents you the critical load factors. You can then perform an evaluation of stability risks. For member models, the resulting effective lengths and critical loads of the members are displayed to you in tables.

Use the next result window to check the normalized eigenvalues sorted by node, member, and surface. The eigenvalue graphic allows you to evaluate the buckling behavior. This makes it easier for you to take countermeasures.


1,450.00 EUR

The prices apply to the use of the software in all countries.

3D Model of the Vocational School in RFEM (© Eggers Tragwerksplanung GmbH)

Special Solutions

First, the two-part Optimization & Costs / CO2 Emission Estimation add-on finds suitable parameters for parameterized models and blocks via the artificial intelligence (AI) technique of particle swarm optimization (PSO) for compliance with common optimization criteria. Second, this add-on estimates the model costs or CO2 emissions by specifying unit costs or emissions per material definition for the structural model.

Price of First License
1,650.00 EUR
Pushover Analysis

Dynamic Analysis

Earthquakes may have a significant impact on the deformation behavior of buildings. A pushover analysis allows you to analyze the deformation behavior of buildings and compare them with seismic actions. Using the Pushover add-on, you can analyze the seismic actions on a particular building and thus assess whether the building can withstand the earthquake.

Price of First License
1,450.00 EUR
Cross-Laminated Timber (CLT) Building


The Multilayer Surfaces add-on allows you to define multilayer surface structures. The calculation can be carried out with or without the shear coupling.

Price of First License
1,250.00 EUR

Time History Analysis for RSTAB 9

Dynamic Analysis

Price of First License
1,450.00 EUR