Add a Thickness Change node to incorporate an expression for how the thickness of a shell or membrane changes as a function of time. This feature is only used in time-dependent studies. The intended applications are when the thickness varies due to wear, corrosion, electrodeposition, or similar processes. In many cases, the expression for the rate of change will thus depend on variables computed elsewhere.

To incorporate a changing thickness, select Thickness rate, top surface and/or Thickness rate, bottom surface, as applicable. Then, enter expressions for the thickness change rates, ∂Δtop/∂t and ∂Δbot/∂t.

The current thickness will be computed as d0 + Δtop(t) + Δbot(t), where d0 is the original thickness given in the parent Thickness and Offset node.

The additional thickness is a field as function of the spatial coordinates, and it will be approximated by a set of shape functions. Select a Shape function type — From physics, Discontinuous Lagrange, or Gauss point data. When selecting From physics, the additional thickness field is approximated by the same shape functions that are used for the dependent variables of the physics.

Physics tab with Thickness and Offset node selected in the model tree: