Hygroscopic Swelling
The Hygroscopic Swelling multiphysics coupling node () is used 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.
Hygroscopic swelling is an effect of internal strain caused by changes in moisture content. This volumetric strain can be written as
where βh is the coefficient of hygroscopic swelling, Mm is the molar mass, cmo is the moisture concentration, and cmo,ref is the strain-free reference concentration.
This feature requires a license of either the MEMS Module or the Structural Mechanics Module. The multiphysics feature will appear automatically if both the Transport of Diluted Species and the Solid Mechanics interfaces are added to the same component. For the most current information about licensing, please see www.comsol.com/products/specifications/.
Further Reading
More information about how to use hygroscopic swelling can be found in the Hygroscopic Swelling section in the Structural Mechanics Module User’s Guide.
More information about multiphysics coupling nodes can be found in the section The Multiphysics Branch in the COMSOL Multiphysics Reference Manual.