The volumetric strain due to intercalation is given by a function dV(c) = ΔV/V0, where ΔV is the change in volume due to intercalation with respect to a reference volume V0. In case of small strains, the intercalation strain tensor reads

where I is the identity tensor and cref is the value of the concentration for which no volumetric strain due to intercalation occurs. For geometrically nonlinear studies, the intercalation strain is represented by the deformation gradient

The Intercalation Strain subnode is only available with the Battery Design Module, see www.comsol.com/products/specifications/).

Select how to define the Volumetric strain dV — From material or User defined.

When From material is selected, the material property Volumetric strain is used. The value of the selected Concentration is then passed to the material using the input in the Model Input section. Add the Reference volumetric strain dVref for which the strain tensor εic should evaluate to zero or the deformation gradient Fic should evaluate to one, respectively.

For User defined, enter an expression for the volumetric strain, dV(c), as a function of a concentration variable to satisfy

Physics tab with Linear Elastic Material, Nonlinear Elastic Material, or Hyperelastic Material node selected in the model tree: