i'm try to running a simulation on a rigid pvc panel with an internal honey comb structure. the panel is 8m by 0.4m by abt 20mm thick. i managed to get all the constraints and forces in but when i want to run the simultion an error pops up saying "thickness not defined in one or more shells". The the outside layers of this panel are 2mm thick and the honeycomb structure is oriented at 45 degrees to the length of the panel with 50mm spacing. Can anybody give me some advise on what i'm doing wrong? I've attached the sldprt file if anyone can take a look at it. It must be a simple issue but i'm very new to solidworks and not yet familiar with how everything works. anybody's help would be much appreciated.

-josef