I have a construction with a rectangular cross section which is made by two halfs each one is a shell U shape. One side of the assembly is fixed and to the other side there is a force 1000N located to lower half of the box. During simulation due to the action of the force the lower half is bending and moving while the upper half is immovable and is not following the motion of the lower half. Also all the stress going to the lower half and the upper one is unstressed completely. Normaly due to the force both halfs must move together as a box and also have stresses both of them. I tried to apply a local bonding contact between the two shells but I receive the message that faces along thickness of sheetmetal is invalid selection so I don't know which faces to select in order to bond the two shells. Can somebody tell me how I will bond the two shells in order to perform together as a box and not separetally. I am attaching a zip file with the example for your help.