Resolving Out-of-Plane Displacement in Ansys ACP — Lesson 3

Why does it lead to out-of-plane displacement, while applying tensile displacement on a composite shell built in Ansys ACP? 

If only one oriented selection set is defined, then the plies are piled up on the middle surface in one direction only (upwards or downwards). This creates an offset on the resulting shell, and applying a displacement on its edge will show coupling between tension and flexion.
This can be resolved by using the "middle offset" option inside the element sets definition, or by using two oriented selection sets to pile up the plies in both normal directions so as to obtain a laminate that is symmetric towards the middle surface plane.