Efficient Design of the Fuel Case of the Lv “Vega” Orbital Stage Using Topology Optimization

The development of new aircraft manufacturing technologies makes it possible to create improved designs. In the article, we have studied the design element of the fourth stage fuel compartment of the launch vehicle (LV) «Vega» — AVUM (Attitude Vernier Upper Module). This element is called a case. Its function is to connect four fuel tanks into a single fuel compartment. A new version of the design is proposed based on the analysis of load conditions of the previous research object. While designing the aircrafts there are opposite criteria which should be met. On the one hand, the design must be strong, rigid, stable and at the same time have the least weight. Additive technologies have fewer restrictions on the complexity of designed geometry than traditional ones. Modern methods of topological optimization make it possible to determine the direction of force flows in a structure. Based on this data, the optimal design is determined to take into account the requirements of working capacity and minimum weight. The combination of new technologies with topological optimization methods allows to design parts more efficiently. Currently, metal 3D printing technology is developing in the direction of reducing restrictions on produced parts dimensions. It is possible to manufacture fuel tanks up to 2400 mm in diameter using additive manufacturing technique. Therefore, the proposed design of the AVUM fuel compartment case does not change main tactical and technical characteristics of the stage. The ultimate load cases were taken according to requirements for the LV «Vega». The proposed design option is based on the previously developed solution of replacing the flat plate with a spherical bottom with holes for the tanks. The application of topological optimization is considered in this paper to create a design option with minimum mass. Topological optimization was carried out for all load cases and, based on the obtained results, a superposition of the retrieved solutions was performed. A rational design option was (modelled/generated) based on the analysis of the obtained results with consideration of the technological restrictions. The fulfilment of the strength conditions for the designed geometry was approved with verification static analysis. As a result of the topology optimization, the mass of the final design is 30% lower than for the original one.