...
All load from main and drogue parachute opening will go through the Payload bulkhead (whereas we expect all reaction load from piston separation to go through the Avionics bulkhead). While we are currently working to qualify an upper bound on deployment forces, we ran some simulations at 3000lbs (an over-estimate) in order to determine an approximate thickness. In these simulations, we applied the load evenly between the four bolt holes and fixed the lower surface of the upper lip as a fixed geometry. Part material was Aluminum 6061. We All runs were performed under the finest basic mesh but we did not control for mesh between runs or refine the mesh for individual runsbolt holes.
For our first run, we tried a Bulkhead with a upper and lower step thickness of 0.5" each. The results showed that this bulkhead would not yield under 3000lbs:
Then, we reduced the thickness to be 0.25" on each step.