Strukturelle Optimierung der SpaceLiner Passagierkapsel unter Verwendung reduzierter Modelle

Kurzfassung

The Space Launcher Systems Analysis Group (SART) of the German Aerospace Center (DLR) is developing the SpaceLiner, a two-stage, rocket-powered hypersonic transport system for intercontinental passenger flights. The structural design of such a capsule requires accurate estimation of stability limits and structural mass already in early design phases. Conventional methods often provide only rough approximations, while detailed finite element (FEM) analyses, though highly accurate, are unsuitable for extensive parameter studies due to their computational cost. This thesis investigates whether reduced models can provide sufficiently accurate estimates of critical loads for stiffened conical shells under axial loading, enabling their use as design tools in early development phases. For this purpose, the in-house analysis tool Melody was methodologically and programmatically extended to account for conical geometries in addition to cylindrical ones. Validation was carried out through comparison with parametric, nonlinear FEM analyses. The results indicate that Melody can qualitatively predict stability phenomena such as local panel buckling and panel instability with high reliability. However, quantitative discrepancies remain, which currently limit its use as a stand-alone tool in the design process. Thus, the research hypothesis was supported in principle but could not be fully confirmed.