Common Settings for Nonlocal Couplings

The following sections in the windows for the nonlocal coupling nodes are similar or the same for some of the nonlocal coupling nodes and are described in this section.

Enter a name for the operator in the field or use the default name. This is the name that is used to access the operator in the model, so use a name that describes it well. For example, genext1 is the default name for the first General Extrusion coupling operator, and you can use it to evaluate a temperature T in the destination using genext1(T), for example.

The source selection defines the source for the nonlocal coupling — the part of the geometry where the coupling operator evaluates the supplied expressions.

From the list, select , , (3D only), or . Select or , , , or from the list. If is selected, select geometric entities in the window. Select , for example, to add all applicable geometry to the list.

	The selection of Source Vertices and Destination Vertices define the linear mapping from the destination to the source.

Click the button to activate one of the vertex selections. You can toggle between turning ON

and OFF

selections.

Select a single source vertex for each of , , , and . Then select a single destination vertex for each of , , , and (vertex 4 is available for Linear Extrusion only).

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For Linear Extrusion: The number of source vertices must be at least one and not more than 1+min(srcsdim,dstsdim), where srcsdim and dstsdim are the dimensions of the source and destination geometries, respectively. The number of destination vertices entered should be the same as the number of source vertices. If not all destination vertex selections are used, the empty selections must be last.

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For Linear Projection, select srcedim+1 source vertices where srcedim is the dimension of the source selection. Depending on the dimension of the source selection, it can be that some of the last source vertex selections should be left empty. The number of destination vertices should be one less than the number of source vertices. If not all destination vertex selections are used, the empty selections must be last. Select srcedim destination vertices where srcedim is the dimension of the source selection. Depending on the dimension of the source selection, it can be that some of the last destination vertex selections should be left empty.

An evaluation point in the destination geometry is first orthogonally projected onto the linear space spanned by the destination vertices (unless they span the entire space). The projected point is then mapped to the source geometry by a linear mapping taking each destination vertex to the corresponding source vertex. Let L be the line through this point, which is parallel to a line through the first and last source vertices. If the source selection lies in the linear space spanned by the source vertices, the Linear Projection operator is evaluated by integrating along L. In general, the operator is evaluated by integrating along the line or curve in the source selection, which is mapped to L under orthogonal projection onto the linear space spanned by the source vertices.

Select or from the list to define the source selection. If is selected, select boundaries in the window. Select to add all boundaries to the list.

There can only be one destination boundary. Click the button to enable or disable the selection. Then choose the boundary in the window.

Select a to use in the source. In most cases the section default settings can be used. Optionally, select the check box and enter expressions in the , , and fields (in 3D) for the source map from the source to the intermediate mesh.

For the General Extrusion nonlocal coupling, the number of source map expressions is the same as the number of destination map expressions. With the default source map expressions, the intermediate mesh can be considered identical to the source.

The dimensionality idim of the intermediate space is determined by the number of nonempty source and destination map expressions, which must be the same, and must also satisfy srcedim ≤ idim ≤ srcsdim, where srcedim is the dimension of the source selection, and srcsdim is the dimension of the source geometry.

For the General Extrusion, Linear Extrusion, Boundary Similarity and Identity Mapping nonlocal couplings, select an option from the list to specify what should happen if an evaluation point in the destination is mapped to a point outside the source:

Enter a scalar positive value in the field. If the mapped point is within a distance of the extrapolation tolerance times the mesh element size, the point is considered to be in the source. Otherwise, the mapping fails.

Select the check box to evaluate the operator to NaN (Not-a-Number) if the mapping fails. Otherwise an error occurs.

For the Integration and Average couplings, select or from the list. In most cases use integration. Summation over nodes is useful, for example, for calculating reaction forces.

	You can only use the Summation over nodes option for expressions that have uniquely defined values in the nodal points.

If is selected, enter a value in the field (see integration order in the Glossary). Also, when working with multiple frames, select a from the list for the volume element to be used in the integration.

For axisymmetric geometries, the check box is selected by default to perform the integration in 3D (for a 2D axisymmetric model) or in 2D (for a 1D axisymmetric model).