Preliminary structural design of a metallic interstage for launch vehicle hot-staging

This work conducts a preliminary structural design of a metallic interstage for a future European mini launch vehicle employing hot-staging separation. The interstage consists of two main components. The first component is a vented cylindrical shell comprising three stainless steel pillars, while the remaining circumference is formed by curved aluminum alloy vented panels to ensure the exhaust gas evacuation. The second component is a truncated cone deflector that redirects the exhaust flow, contributes to the separation force, and is internally stiffened by stringers and frames. Both components are designed to guarantee structural stability and strength under the operational loads. The study does not consider thermal effects. The methodology combines analytical formulations with finite element analyses using ABAQUS. The investigation leads to a design that satisfies the structural requirements, with the deflector reinforced by Tstringers and Omega-frames to improve buckling resistance. The numerical results differ about 7.3% from the analytical simplified models.