COMSOL 6.3 - Solid

The node adds the equations to model the Fickian diffusion in solids. The node allows for specifying the diffusion properties of each species.

The is selected by default. The list contains all applicable coordinate systems in the component. The coordinate system is used for interpreting directions of orthotropic and anisotropic material data presented in a local system. The coordinate system must have orthonormal coordinate axes, and be defined in the material frame. Many of the possible subnodes inherit the coordinate system settings.

Use this section to specify the diffusion coefficient for each species.

From the list select or a material available in the model to select a diffusion coefficient.

Enter the , Dc, for each of the species.

For , select , , or to enter one or more components. When anisotropic inputs are used, the axis orientations are given by the Coordinate System Selection.

To display this section, click the button (

) and select in the dialog. The mobility is used by the Shrinkage and Swelling multiphysics coupling to compute stress-driven fluxes.

Select the — , , or .

When is selected as the , the mobility of each of the species is linearly related to the concentration

When is selected as the , enter the cmax for each of the species. The default value is Inf mol/m3. The mobility of each of the species is defined as

For , select , , or to enter one or more components of the . When anisotropic inputs are used, the axis orientations are given by the Coordinate System Selection.

To display this section, click the button (

) and select in the dialog.

This setting is only available when the model includes deforming or rotating domains, for example when using a node or a Structural Mechanics interface. From the list, select or to specify the diffusion coefficient values in the reference (material frame) or in the deformed (spatial frame) configuration. They are related as follows,

Physics tab with selected: