I am analysis a repair problem. Please refer attached picture. The initial plate (305mmx206mmx1.6mm) has supported some installations. To facilitate installations, the holes were blanked in the panel.
Now, the new design is void of those installations. Hence these holes need to be covered. To cover those, designer is simply fastening one more panel (same dimensions) of thickness 1.8mm to the existing panel. The material of the both panels is 2024-T3. The panel is subjected to a pressure of 2dp (Not a primary structure/skin panel). When I carry out panel bending analysis using Roark, the plate is failing. Here I am assuming the lower panel with holes (original plate) is ineffective in taking the loads.
I don't have the reference of original analysis. Now I need to clear the repair. I would like to ask your opinion regarding this. Do I need to suggest increase in thickness or material? I feel it is a geometric non linearity problem, Is there any way to clear the present scheme by hand calculations so that change in material/thickness is avoided. Your reply is appreciated. Thanks in advance.