Structural Optimization of Metal Bulkheads of Pressurized Modules for Space Applications

This thesis presents the work carried out to build a CAE model and execute an optimization analysis to define the ideal structural frame of two pressurized doors in aluminum alloy. The two doors are expected to be used, the first as an optimized docking hatch for manned modules for terrestrial or lunar orbiting stations, and the second as an EVA door for Moon or Mars future ground bases. The analysis was carried out using sizing or dimensional optimization models and, also as a second option, trying to identify a workable topological optimization. Both option aiming to reduce the mass of the hatches as much as possible. To implement this optimization, the Altair HyperWorks software suite was used. In particular, the hatches were modeled using HyperMesh, initially starting from simple plate modeling and evolving step by step to a beamed hatch structure, each step moving forward approximating the physical implementation reality. All the optimizations were then executed in OptiStruct. Finally, HyperView was used to graphically present the simulation results and to interpret the achievements. The simulations found that substantial structural optimization can be pursued (within the manufacturing limits), offering a clear indication that the weight of the hatch could be optimized. Further studies will naturally be required in terms of evaluating additional constraints needed to ensure the survivability of the hatch component, e.g. considering the acoustic pressure load at launch, and by adding extra mechanical components to the model (locking, portholes, etc.). This work was carried out at the Thales Alenia Space - Italy company, Turin premises under the supervision of Engineers Paolo Spinolo, Andrea Giglio and Marco Mazzetti and, for Politecnico of turin DIMEAS, Professor Alfonso Pagani. The outcomes are now being used by Thales Alenia as a basis to improve the structural design of the two hatches.