In SpaceClaim, I offset the edges of the 2D planar surface to get curves on the centerline of each flexure. Then I used the Pull tool to pull the curves along the Z axis to create the surfaces. In Mechanical, each surface is assigned a material and a thickness. The 3D surfaces are meshed with Shell elements in a 3D analysis. Shell elements have equations that compute bending of the shell.
The Force Reaction is for the Remote Displacement at the top. The force is the Y component only so represents the vertical force. You could multiply the force by 2 to include the other half of the cell that was not in the model.