171x
003582
2024-02-13

Static Deformation

In the case of the 'Static Deformation' imperfection type, the imperfections are based on the deformations of a load case or a load combination.

In the 'Static Deformation' tab, select a load case or load combination as the source for the deformation, or create a new load case or load combination.
When selecting a new load case, you should make sure that it is defined without an action category, so that it is not considered in the load combinations.

Tip

Use the structure modification of a load case or load combination to change, for example, the stiffnesses, supports, and hinges of your structural system. Thus, it is possible to generate any deformations that are independent of the boundary conditions of the actual structure. Explanations of the structure modification options can be found in the RFEM Manual.

If you want to generate the imperfection from the deformation of an existing load combination, it is necessary to copy it beforehand and deactivate the consideration of the imperfections. Then, select the copied load combination as a basis for the imperfection.

Imperfection Magnitude

As in the case of the imperfection type Buckling mode, you should also select a reference point and a scaling direction. The deformation from the selected load case is scaled in such a way that the specified deformation value in the scaling direction is reached at the reference point. Thus, the load values in the specified load case or load combination have no meaning for the resulting imperfection.

Important

When creating the imperfection, all deformation directions are taken into account, in particular the warping of a cross-section if the load case or load combination has been calculated with 7 degrees of freedom.

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

Applying an imperfection in this way is well suited when calculating a large number of members. It is possible to generate individual imperfections, since the deformation can be specified as required by freely selecting loads and structural modifications. However, you have to estimate which approach gives the most unfavorable imperfections.

Parent Chapter