Entwicklung und Test von Krafteinleitungen für keramische Sandwichstrukturen (Masterarbeit)

The goal of this thesis is to design, develop, and test reinforcements of the core around a mounting point within a ceramic matrix composite (CMC) sandwich structure. The CMC sandwich structure must provide physical and thermal stability for use on an optical bench on satellites. This mounting point is integrated into a CMC sandwich structure with a grid core and must be locally reinforced to distribute the resulting forces further into the structure. Due to the C/C-SiC in-situ manufacturing method for these sandwich structures, these local reinforcements must be integrated early in the manufacturing process. At first, small feasibility samples were manufactured with three potential different reinforcement concepts. These samples were non-destructively tested to qualitatively evaluate the joints between the reinforcement cell fillings and the grid core, as well as the fillings and sandwich skins. The findings from these tests were incorporated into further feasibility samples until a satisfactory joint was reached and a viable manufacturing process established. The most promising filling and joining method was then applied to a large sample called the “XXL interface sample”. Three samples were manufactured and tested with a quasi-static cyclic tensile test to ensure that the parts can withstand a force of 4,3 kN, as well as exhibit physical stability after repeated loading. The goal of these samples is to have no permanent deformation after loading. These goals were reached and experimentally proven. Using ANSYS FEM Software, the manufactured test sample is simulated with the same testing parameters as the cyclic tests. The displacements between the physical test and simulation are correlated to determine the feasibility of the simulation. In the future, different reinforcements can be simulated using this baseline FEM to further optimize the structure in terms of weight, strength, filling structure, manufacturability, cost, etc