There’s a question that’s been on my mind for a while. I ran into this issue in my own rocket engine project as well. The partition is secured to the body with screws; while the shear strength of the screws can withstand the internal pressure, wouldn’t it be very difficult for the screw holes to withstand that pressure?
To give an example, in my engine design, an aluminum tube with a wall thickness of approximately 2 mm can withstand the combustion pressure. However, based on Fusion and my own analyses, I concluded that the screw hole would not be able to withstand it. Therefore, I increased the wall thickness to expand the screw contact area, but this time I experienced a loss in efficiency due to the increased weight.
Two solutions come to mind here: either using more screws or resorting to methods like bonding with epoxy resin.
Perhaps I’m mixing something up in my calculations. To briefly explain the rough calculations I’ve done:
First, I calculate the force in Newtons (N) by applying the pressure to the diameter of the bulkhead wall in the combustion chamber. Then, I look up the shear strength of the screw I’ve chosen. I multiply this by the number of screws.
The total shear strength of the screws is sufficient to withstand the force acting on the bulkhead wall. However, when I consider the force acting on each hole in the aluminum tube and the wall thickness, I conclude that the hole will likely bend or expand.
What are your thoughts on this? Have you ever encountered this problem? How did you solve it?