Louis Girardin

More details: I have a complex cylinder-shaped structure with two inner surfaces creating two chambers inside the cylinder. There is a void between these inner surfaces. The outer wall of this structure moves with a specified displacement. What I want to achieve is for the two inner surfaces to move in response to the pressure difference between the two chambers. These inner surfaces should move symmetrically, meaning when one surface moves, the other one should move in the same direction and by a similar amount. This symmetry is maintained because the distance between the two surfaces remains roughly constant.

I initially applied a specific displacement along one axis, but due to the curved surface, I encountered issues with negative volume for larger displacements. To address this, you are considering using the "Normal Y * DisplacementExpression" to align each node along the normal direction, which would help maintain the structural integrity of the model

So far I have applied a specific displacement following only one axis as the nodes are globally oriented in the y direction, however as it is a curved surface, I run into negative volume for the largest displacements.