Structural analysis and optimization of the innovative space launch vehicle Bulldog Puppy

The purpose of this thesis is to investigate the structural behavior of an innovative pyramidal shape space launch vehicle designed for joining the “Heinlein prize for the advances in space commercialization” that gives an award for practical accomplishments in the field of commercial space activities. The space industry is seeking for innovative commercial activities and one of these is the asteroid mining that could be a valuable source of metals for construction in the space environment or for transporting them back to the Earth. Many private companies are trying to develop their own space launch vehicles in order to find new solutions for decreasing the unitary cost per mass of payload launched. The Bulldog patent was designed with this aim and a preliminary feasibility study created the cad model of the Bulldog for bringing 13500 kg of payload and a scaled version named Bulldog Puppy for bringing 1000kg of payload in low Earth orbit. This thesis is focused on the results validation and prosecution of the previous work about the Bulldog Puppy launch vehicle. The analysis was made using the widely spread method of FEA. It started from the meshing of the Cad model coming from the reference study using a more accurate software for the preprocessing. The first investigation made was a whole structure free-free modal analysis that showed a bad dynamic behavior with many local resonances and coupled modes due to the incorrect connection design. From these results an iterative set of structural improvements were performed stage by stage considering the mass and costs optimization and a brand-new design for the payload fairing opening was purposed. The following step was the execution of a 2G and 4G acceleration stress analysis on the modified model that denoted a performance improvement in comparison with the reference structure but showed some local connections that need to be refined. Future analysis can be performed for sizing the fuel tanks, covering skins and engines for making the model more complete and evaluating the production of a prototype model. The results of this investigations can be used as reference for future development of the Bulldog Puppy project.