Linear Elastic Material

The node adds the equations for a linear elastic shell and an interface for defining the elastic material properties.

By adding the following subnodes to the node you can incorporate many other effects:

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Thermal Expansion (for Materials)

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Hygroscopic Swelling

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Initial Stress and Strain

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External Stress

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Damping

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Safety

A Shell Local System subnode is always added. In this node you specify the coordinate system in which material orientations and results are interpreted. You can add several nodes in order to control the local directions on different boundaries.

Linear Elastic Material

Select a linear elastic — , , or and enter the settings as described for the Linear Elastic Material for the Solid Mechanics interface. Note that:

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For no values for Ez, νyz, or νxz need to be entered due to the shell assumptions.

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For a 6-by-6 symmetric matrix is displayed. Due to the shell assumptions, you only need to enter values for D11, D12, D22, D14, D24, D55, D66, and D56.

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The material orientation is always interpreted in a local coordinate system aligned with the shell boundary as described in Local Coordinate Systems.

Out-of-Plane Strain

To display this section, click the button (

) and select in the dialog box.

If the check box is selected, extra degrees of freedom will be added for computing the out-of-plane strain components. This formulation is similar to what is used for plane stress in the Solid Mechanics and Membrane interfaces, and it is computationally somewhat more expensive than the standard formulation. In the default formulation, the out-of-plane strain in the shell is explicitly computed from the stress. This may cause circular references of variables if you for example want the constitutive law to be strain dependent. If you encounter such problems, use the alternative formulation.

Geometric Nonlinearity

In this section there is always one check box. Either or is shown.

If a study step is geometrically nonlinear, the default behavior is to use a large strain formulation in all domains. There are however some cases when you would still want to use a small strain formulation for a certain domain. In those cases, select the check box. When selected, a small strain formulation is always used, independently of the setting in the study step.

The default value is that the check box is cleared, except when opening a model created in a version prior to 4.3. In this case the state is chosen so that the properties of the model are conserved.


	The Include geometric nonlinearity check box is displayed only if the model was created in a version prior to 4.3, and geometric nonlinearity was originally used for the selected domains. It is then selected and forces the Include geometric nonlinearity check box in the study step to be selected. If the check box is cleared, it is permanently removed and the study step assumes control over the selection of geometric nonlinearity.

Location in User Interface

Context Menus

Ribbon

Physics tab with selected: