Layered Material

), you can specify the properties of a multilayer laminate. It is used when defining the properties of the following features:

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in the Shell interface (requires the Composite Materials Module).

A node can be present in two locations in the Model Builder:

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The most common place is under . When you reference a layered material from a physics interface, you do it indirectly through either a Layered Material Link or a Layered Material Link (Subnode) under in the current component.

In this table you specify the properties of each layer.

Click the button (

) to add another table row. Use the (), (), and (

) buttons to organize the table as needed. To completely reset the table to its default state, you can use the button ().

Conceptually, the layers are ordered from bottom to top of the laminate. Enter the following data in the table:

Here you can assign a name to the layer for future reference. The default is a sequential numbering: Layer 1, Layer 2, and so on.

Select any available material. If the node is located under , the list contains only global materials. If the node is used as a subnode to a , also materials defined under in the component are available.

When you have a certain row in the table selected, you can access three shortcuts:

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Click the (

) button to add a new blank material under global materials. The material is referenced in current row of the column.

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Click the (

) button to add a new material under global materials from Material Libraries. The material is referenced in current row of the column.

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Click the (

) button to jump to the definition of the material selected on the current row.

When you add a new row to the table, the same material as on the previous row is selected. This means that if you have many, not adjacent, layers with the same material, it is more efficient to initially add all layers with that same material. Then you can go back and change the material for some layers. Alternatively, you can reorder the layers using the () and () buttons.

If the material in the layer is orthotropic or anisotropic, enter the angle in degrees (positive counterclockwise) from the first principal axis of the laminate to the first principal axis of the layer. Even for an isotropic material, the orientation can matter for result presentation, since it affects the interpretation of for example stress tensor components.

Enter the thickness of the layer (default unit: m). The thickness can be numeric value or a scalar parameter.

In the physics interfaces, the layered materials are handled through the concept of a virtual extra dimension. For a layered material defined on a boundary, you can think of that as an extra coordinate in the normal direction. Enter the number of elements that you want in the extra dimension for the layer.

In some physics features, not only the layers themselves but also the interfaces between them are important. In such a case, you can assign materials to the interfaces in this table. The number of interfaces is one more than the number of layers because the free top and bottom surfaces of the laminate are also considered as interfaces.

In most cases, you do not need to enter anything in this section.

This is the interface name, for future reference. As a default, the interface name is constructed from the names of the two adjacent layers. For the top and bottom interfaces, the labels “up” and “down” are used for the two exterior sides.

You can rename the interfaces. This is, however, seldom needed.

This column shows the location of the interface. The distance is counted from the bottom of the laminate. The column is for information only, and cannot be modified.

Select the material of the interface. You only need to assign materials to the interfaces that are explicitly referenced by physics features. The default is to take the material . The interface material properties are then computed from the adjacent layers’ material properties.

Figure 9-8 shows an example of the settings for a layered material. The layer names have been entered manually, whereas the interfaces have retained their default names.

You can save the laminate definition to a text file by clicking the (

) button. For the example above, the text file has the following contents:

To load a text file on this format, click the (

) button. For complex laminates, it may be easier to start by creating the text file representation in a text editor, than to enter the data in the GUI.

	When loading a file, the second column containing the material tag is ignored. The reason is that there is no way to ascertain that a material tag like ‘mat2’ would point to the same material in another context. You can even load a file where that column is absent.

You have two options for visualizing the laminate defined in the node. To see the thickness of each layer, click the (

) button. This will give a plot like the one shown in Figure 9-9.

To visualize the layer orientations, click the (

) button. In Figure 9-10, an example of such a plot is shown. The x-axis corresponds to the principal laminate direction, and the stripes indicate the principal direction of each layer.

In this section, you can fine-tune the display in the preview plots.

In the text field, you can enter a value for the spacing of the stripes showing the orientation of the principal orientation of the layer. The layer itself is always drawn as a square with the unity side length. If you deselect the corresponding check box, no orientation lines are drawn.

The value of the is used by both types of preview plots.

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In a layer stack preview plot, it controls the height of the stack in the z direction. For laminates with many layers, you may need to increase this value.

Clear the check box to remove the text labels showing layer names and materials.