AutoFEM Buckling Analysis

Using the AutoFEM Buckling Analysis module, mechanical engineers and construction experts who work in the AutoCAD medium are able to carry out calculations of the mechanical stability of the structure. The essence of the stability computation is as follows. Sometimes, mechanical structures which satisfy conditions of strength in the face of static loads may spasmodically collapse when significant forces are applied to this system. This physical phenomenon is usually called “the loss of stability”. Stability calculation is crucial, for instance, for high structures in which forces are directed along them. The Euler’s classical stability calculation implies the determination of the “Factor of Critical Load". This factor is computed for some "trial” and preset mechanical load and allows one to estimate the value of the maximum permissible load on the mechanical system, which, when exceeded, leads to the stability loss. This load is defined as the product of the trial load value and the calculated factor of critical load. Along with the critical load factor, as the result of the stability calculation, the user will obtain the expected form of stability loss, which shows possible deformations of the structure in the case of the loss of stability. If the calculated critical load factor is negative, this means that for the preset load conditions, there will be no stability loss.

In the parameters of the problem of stability one can determine the number of forms of equilibrium states to be determined and other parameters of calculation.

As a result of the buckling analysis, values of the coefficients of the critical loads at which there is loss of stability are obtained, as well as appropriate forms of instability.

The critical load factor means - the estimated value of the coefficient, the product of which on applied  load, gives the actual value of the critical load, causing the system to a new equilibrium. For example, the model is applied distributed force 1000 N. Ratio of the critical load of the calculation results was 109.18. This means that the first form of stable equilibrium for this model has a critical load of 109180 N.

The relative displacement (buckling mode) is a shape of the equilibrium steady state corresponding to a certain critical load. Forms of equilibrium states that are displayed in the window Postprocessor after the calculation represent the relative displacement. Analysing these forms you can draw conclusions about the nature of displacement in situations of instability. Knowing the expected equilibrium shape at a certain critical load, one can, for example, specify additional fastening or support in the field of design corresponding to the peak of this form of equilibrium, which would effectively change the mechanical properties of the product.

Buckling modes

Forms of equilibrium states corresponding to the fifth and eighth critical loads of construction.

Below you can find some examples of AutoFEM Buckling Analysis

Verification Examples of AutoFEM Buckling Analysis

Buckling analysis of a compressed straight beam

Buckling analysis of a square plate

Quick Start on AutoFEM Buckling Analysis


This lesson will help you to perform:

·the Buckling Analysis of the structure subjected to specified loads;

·calculation of the critical load at which the structure looses stability by the AutoFEM Analysis Lite.

You will learn to:
create the Buckling Analysis problem;
create the finite element mesh;
specify materials;
specify loads and constraints;
obtain calculation results in the form of color plots.

Download demo video of the AutoFEM Buckling Analysis Module