The Hygroscopic Swelling multiphysics coupling node (
) is for moisture concentration coupling between the Solid Mechanics interface and either the Transport of Diluted Species or Transport of Diluted Species in Porous Media interfaces.
where βh is the coefficient of hygroscopic swelling,
cmo is the moisture concentration, and
cmo,ref is the strain-free reference concentration.
The Label is the multiphysics coupling feature name. The default
Label (for the first multiphysics coupling feature in the model) is
Hygroscopic Swelling 1.
The Name is used primarily as a scope prefix for variables defined by the coupling node. Refer to such variables in expressions using the pattern
<name>.<variable_name>. In order to distinguish between variables belonging to different coupling nodes or physics interfaces, the
name string must be unique. Only letters, numbers, and underscores (_) are permitted in the
Name field. The first character must be a letter.
The default Name (for the first multiphysics coupling feature in the model) is
hs1.
You can select None from either list to uncouple the coupling node from a physics interface. If the physics interface is removed from the
Model Builder (for example,
Solid Mechanics is deleted), then the list defaults to
None as there is nothing to couple to.
Enter a Strain reference concentration cmo,ref . This is the concentration at which there are no strains due to hygroscopic swelling.
Enter the Molar mass of the fluid,
Mm. The default value is 0.018 kg/mol, which is the molar mass of water.
The default Coefficient of hygroscopic swelling βh uses values
From material. For
User defined select
Isotropic (the default),
Diagonal, or
Symmetric from the list to enter one or more components for a general coefficient of hygroscopic swelling tensor
βh.The default value for the
User defined case is
1.5e-4 m
3/kg. When an anisotropic coefficient of hygroscopic swelling is used, the axis orientations are given by the coordinate system selection in the structural mechanics material node to which it contributes.
The Include moisture as added mass check box is selected by default. When selected, the mass of the fluid is included in a dynamic analysis, and when using mass proportional loads. It will also contribute when computing mass properties.