RF-STABILITY Add-on Module for RFEM

Stability Analysis: Buckling Shapes and Imperfections with RF-STABILITY & RF-IMP

Further Information


Receive regular information about news, useful tips, scheduled events, special offers, and vouchers at least once a month.

Stability Analysis According to Eigenvalue Calculation Method

The RF-STABILITY add-on module analyzes the stability of structures. The RFEM add-on module determines critical load factors and the corresponding stability modes.

  1. Features

    • Calculation of models consisting of member, shell and solid elements
    • Import of axial forces from a load case or combination
    • 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
    • Calculation of buckling modes of unstable models
    • Determination of stability mode greater than the user-defined load increment factor (Shift method)
    • Optional determination of the mode shapes of unstable models (to recognize the instability cause)
    • Visualization of stability mode
    • Basis for analysis using imperfect equivalent structures in RF-IMP
  2. Input window


    First of all, it is necessary to select a load case or combination whose axial forces are to be used in the stability analysis. It is possible to define another load case in order to consider initial prestress, for example.

    Then, you can select the linear or non-linear analysis to be performed. Depending on the case of application, you can select a direct calculation method such as the Method by Lanczos, or the ICG iteration method. Members not integrated in surfaces are usually displayed as member elements with two FE nodes. These elements prevent from the determination of the local buckling for an individual member. Therefore, there is the option to divide members automatically.

  3. Global Calculation Parameters


    Several methods are available for the Eigenvalue analysis:

    • Direct Methods
      The direct methods (Lanczos, roots of characteristic polynomial, subspace iteration method) are useful for models of small and medium size. These fast methods of equation solvers benefit from lots of the computer memory (RAM). 64-bit systems use more memory so that even bigger structural systems can be calculated quickly.
    • ICG Iteration Method (Incomplete Conjugate Gradient)
      This method requires only a little memory. Eigenvalues are determined one after the other. It can be used to calculate large structural systems with few stability modes.

    The RF-STABILITY add-on module can also perform the non-linear stability analysis. Also for non-linear structures, the results close to reality are provided. The critical load factor is determined by increasing the loads of the selected load case step by step until the instability is reached. Nonlinearities such as failing members, supports and foundations as well as material nonlinearities are considered when increasing the loads.

  4. Graphical evaluation of eigenvalues


    The critical load factors are the first results displayed. They facilitate the evaluation of stability risks. In the case of member models, the module displays the effective lengths and critical buckling loads of the members in the second result window.

    In the next result windows, you can check the normalized eigenvalues sorted by node, member, and surface. The eigenvalue graphics allows for the evaluation of the buckling behavior. The graphical display facilitates the provision of countermeasures.

Contact us


Do you have any questions about our products? Do you need advice for your current project? 
Contact us or find various suggested solutions and useful tips on our FAQ page.

+49 9673 9203 0


Customer Projects

Customer Projects designed by Dlubal Software products

Interesting customer projects designed with the structural analysis programs by Dlubal Software.

PRICE for RFEM (VAT excluded)


    1,030.00 USD

  • Next License

    463.50 USD

RFEM Main Program
RFEM 5.xx

Main Program

Structural engineering software for finite element analysis (FEA) of planar and spatial structural systems consisting of plates, walls, shells, members (beams), solids and contact elements

RFEM Steel and Aluminium Structures

Add-on Module

Design of steel members according to Eurocode 3

RFEM Other
RF-IMP 5.xx

Add-on Module

Generation of equivalent geometric imperfections and pre-deformed initial structures for nonlinear calculations

RFEM Concrete Structures

Add-on Module

Design of reinforced concrete members and surfaces (plates, walls, planar structures, shells)

RFEM Concrete Structures
EC2 for RFEM 5.xx

Module Extension for RFEM

Extension of the modules for reinforced concrete design by the Eurocode 2 design

RFEM Other
RF-MAT NL 5.xx

Add-on Module

Consideration of nonlinear material laws

RFEM Dynamic Analysis
RF-DYNAM Pro - Natural Vibrations  5.xx

Add-on Module

Dynamic analysis of natural frequencies and mode shapes of member, surface, and solid models

RFEM Concrete Structures
RF-CONCRETE Columns 5.xx

Add-on Module

Reinforced concrete design according to the model column method (method based on nominal curvature)

RFEM Dynamic Analysis
RF-DYNAM Pro - Equivalent Loads 5.xx

Add-on Module

Seismic and static load analysis using the multi-modal response spectrum analysis

RFEM Connections

Add-on Module

Design of rigid bolted frame joints according to Eurocode 3 or DIN 18800

RFEM Timber Structures
RF-TIMBER Pro 5.xx

Add-on Module

Timber design according to Eurocode 5, SIA 265 and/or DIN 1052

RFEM Concrete Structures

Add-on Module

Physical and geometrical nonlinear calculation of beam and plate structures consisting of reinforced concrete