Τεκμηρίωση SkyCiv

Ο οδηγός σας για το λογισμικό SkyCiv - μαθήματα, οδηγοί και τεχνικά άρθρα

1. Σπίτι
2. Αναλυτικά Shell FEA
3. Beam Shell FEA – Ξεκινώντας
4. Φροντιστήριο 2. Beam Shell FEA (Προχωρημένος)

# Φροντιστήριο 2. Beam Shell FEA (Προχωρημένος)

## Example Overview

In this advanced example you will continue to investigate the behavior of the previous beam, but now in terms of nonlinear static analysis.

The linear static and linear buckling analysis performed previously allows to quickly analyze and optimize the structure. Ωστόσο, sometimes it is necessary to see the ‘real pictureof the failure. See how plasticity is distributed in the elements, what the values and how the geometric imperfection affects on the buckling.

In order to see this final picture of failure the nonlinear static analysis must be considered. This analysis considers external loads by portions (or steps), where the material and geometric nonlinearity considered to determine the stress-deformed shape at each step.

## Βήμα 1. Mesh Refinement

In the Mesh panel define the mesh size for all edges and openings 35 χιλ, making the global model mesh more coarse than it was previously. Then go to the Refinement tab. Define row in the table and the mesh refinement zone starting from (Ρ1) 100 mm and ending (Ρ2) στο 850 mm from the beginning of the beam. The mesh size in this zone is 15 χιλ. Generate the mesh for the model and observe how the more dense mesh is created in the first web panel.

## Βήμα 2. Nonlinear Material Properties

In the Materials panel define plastic stress and strain properties of the materials. Beam parts are made of steel with yielding stress values of 230 MPa for the web and 245 MPa for other components.

Define a bi-linear diagram that includes two zones: linear and plastic. First set Modulus of Elasticity (μι) για χάλυβα. In the second row of the table create ‘plasticzone with the same value of plastic stress Repeat this procedure for the other beam components like the flanges and stiffeners with the plastic stress of 245 MPa.

## Βήμα 3. Web Imperfections

Define imperfections to web panels 2 και 3. Define two rows and select web panels. Define the direction of imperfection and magnitude (Ρ1) όπως και 2 mm for the one panel and -2 mm for another panel. Click the Preview button to see how it affects on the FE model geometry during the analysis.

Remove previously defined forces from the stiffeners. Then in the Displacement Stiffeners panel apply a displacement load along the y-axis of 40 χιλ.

## Βήμα 5. Nonlinear Analysis

In the Analysis panel select the Geometry and Material Nonlinear Static Analysis Type. Click the Analysis button.

## Βήμα 6. Displacement results

In the Result Step select the final step (1.0). Select the displacement component and include the deformed view with a scale of 1.

## Βήμα 7. Plasticity Results

Select Plate side view both and click Display to see the plastic strain contour plot. Εδώ, a value of zero means that the element has no plasticity. Define in the Limit Strain field 5% and click the Status button. Σαν άποτέλεσμα, you will see the safe and unsafe zones of the structure.