The structural model can be coupled with the battery swelling model to simulate battery cell deformation caused by electrochemical effects and deformation of the battery electrode layer. Battery swelling effects are only available for the linear or nonlinear structural models and when the battery swelling model is enabled as outlined in Inputs for the Newman’s P2D Model in the Fluent User's Guide.
To simulate battery swelling effects, the structural model works in conjunction with
the battery swelling model. The battery swelling model provides the electrode layer
strain scalar
and the electrode layer normal vector
to the structural model to solve for the swelling strain tensor
. momentum balance, and swelling stress tensor
. After the structural model computes the above terms, they are
provided to the battery swelling model to solve the relevant E-chem submodel equations.
The variables that are passed between the structural model and the battery swelling
model are referred to as coupling variables.
When using a dynamic mesh, the electrode layer normal vector
is transformed into the deformed frame battery layer normal vector
following the local rotation of the battery geometry and formulated
as:
 | (16–38) |
with 
being the identity matrix and 
being the deformation gradient. Note that when a dynamic mesh is not
used for the battery geometry, will be equal to .
The swelling strain tensor
is then reconstructed from the electrode layer strain scalar
and
as:
 | (16–39) |
The effective stress induced by battery swelling is then obtained from using the linear isotropic elasticity equation ( Equation 16–3). The following formulation is
recommended for the Young's modulus in Equation 16–3 to ensure the coupling of
variables is consistent with the battery swelling model:
 | (16–40) |
where 
is the Young's modulus and 
is the thickness of the battery sandwich layer component, the
subscripts 
. 
. and 
denote the battery anode, separator, and cathode, respectively (see
Battery Swelling Model. specifically Modeling Swelling in the E-Chem Standalone Mode), and 
denotes the effective Young's modulus used in the linear elasticity
formulation.
To solve for the total stress
on the battery geometry, the momentum equation is solved with the
swelling stress included and defined as:
 | (16–41) |
With the momentum equation solved, the total stress
on the battery geometry is defined as:
 | (16–42) |