COMSOL 6.2 - Hygroscopic Swelling

Use the subnode to add an internal thermal strain caused by changes in temperature.

Hygroscopic swelling can be added to Linear Elastic Material, Linear Elastic Material, Layered, Nonlinear Elastic Material, and Hyperelastic Material. For , swelling can be applied to arbitrary layers in a multilayered membrane when the Composite Materials Module is available.


	See also the discussion in Layered and Nonlayered Membranes.

Shell Properties

This section is present only when the node is used under Linear Elastic Material, Layered.

Select the layer or layers for which this swelling strain contribution is to be added.

Table 7-8: Layer Selections; Hygroscopic Swelling.
Selection	Use All Layers	Selection of Individual Layers
Boundary	Same as parent selection when the node is added.	When Use all layers is not selected.

If the differs between layers, you will need to add several nodes with different layer selections. If only the material data values differ, you can use a single node with . The data for each layer is then received from global nodes.

If the same layer is selected in two nodes being active on the same boundary, the second definition will override the previous.


	Hygroscopic strains are proportional to the concentration, while structural strains are computed from the gradient of the displacement field. It is good practice to match the discretization order of hygroscopic and structural strains. When adding a Hygroscopic Swelling subnode, and the concentration field is computed by another physics interface; use a discretization one order lower for the concentration field than what is used for the displacement field.

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All other settings for the node are described in the documentation for Hygroscopic Swelling in the Solid Mechanics interface.

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For a general description of layer and interface selections, see The Shell Properties and Interface Selection Sections.

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You can provide parameters for the expansion with a through-thickness variation by explicitly or implicitly using expressions containing the extra dimension coordinate as described in Using the Extra Dimension Coordinates.

Location in User Interface

Context Menus

Ribbon

Physics tab with , , , or node selected in the model tree: