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2024-02-13

Scaled buckling figure

By selecting the 'Buckling Mode' imperfection type, you can calculate an imperfection mode based on an imperfection created with the -analyses/structures-stability structure stability

Buckling Mode

Select a load case or load combination as the source of the mode shape. For this load case or load combination, the ' option must calculate the critical load | Structure Stability' add-on. The number of the mode shape is also specified in this dialog box.

If you want to generate the imperfection from the buckling mode of a load combination, you have to copy it beforehand and deactivate the consideration of imperfections. Then, select the copied load combination as a basis for the imperfection.

Important

If the selected mode shape changes after adjusting the model, the created imperfection shape of the imperfection case is also adjusted.

Imperfection Magnitude

Then, select a reference point and a scaling direction for scaling the buckling mode. The selected buckling mode is first normalized, then all components are scaled so that the specified deformation value in the selected direction is reached at the reference point.

Specify the deformation value for the scaling directly or using a formula. Using formulas, you can define dependency on a member length.

Calculation of imperfection case

After calculating the imperfection case, the scaled deformations of the structure considered as an imperfection are obtained as a result of the 'Static Analysis'. This type of imperfection is not taken into account by equivalent loads, but by a displacement of the FE elements in the calculation.

If the imperfection case is assigned to a load case or a load combination to be calculated, the calculation of the imperfection case is carried out automatically.

Use

Tip

This method of applying an imperfection is well suited for a few members that may have complicated boundary conditions. This variant is particularly useful when you cannot directly estimate the approach of the most unfavorable imperfection.

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