Designing of a drone frame is presented in this paper. The main goal is to develop the optimal drone frame geometry. The optimization criterion represents mass minimization along with ensuring the required stiffness. Another intention is to use cheap materials and simple manufacturing technologies. The design process consists of three steps. The first step is engineering of a composite material, which is a three-layer sandwich panel. A series of three-point bending experiments are carried out for material samples. The optimality criterion takes into account both physical and economic features of the material. In the final scheme the outer layers are made of carbon and basalt fabrics, which are impregnated with resin, and a specific non-woven material is used as filler. The second step is the initial design. Dimensions are specified for design purposes. The third step is the optimization process. The finite element model of the frame is developed. The drone weight and the lift forces serve as applied loads. The optimization is implemented by removing material from unloaded areas of the structure. The Nelder–Mead (simplex) method with varying geometric parameters of the structure is used. As a result of the optimization process, the mass of the initial structure is reduced by 25.6 percent.

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Abstract. This paper presents the results of numerical investigations of the interaction with the Mars surface of four supersonic jets of ExoMars landing platform propulsion system. The cases of impingement of supersonic jets on a curved surface are considered depending on the values of propulsion system thrust. According to the results of numerical studies are obtained the values of normal stresses on the surface of Mars at altitudes of 1.0, 0.5 and 0.3 meter to the surface of the landing. To define the occurring shear stresses Mohr-Coulomb theory was used. The maximum values of shear stresses were defined for the following types of soil of Mars: drift material, crusty to cloddy material, blocky material, sand and Mojave Mars simulant. The conducted evaluations showed, regardless of the propulsion system configuration, that when the final stage of the controlled landing of the ExoMars landing platform, the erosion of the Mars regolith would be insignificant. The estimates are consistent with the available data from previous Mars missions.

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