Within the framework of the DESICOS (New Robust DESign Guideline for Imperfection Sensitive COmposite Launcher Structures) funded by the European Comission, the buckling bahviour of imperfection sensitive shell structures is investigated. Due to the high effect of imperfections on the load carrying capacity of shell structures subjected to axial compressive loads, imperfections have to be considered in the design phase. For this purpose, empirical relations, mostly derived with the 1960s such as the NASA SP8007 Guidleine, are applied. With the DESICOS project, it is aimed to develop new design guidelines for unstiffened and stiffened shell structures, leading to structures having beneficial properties in terms of lightweight design purposes.
The European project DAEDALOS includes the numerical and experimental investigation of the effects of transient load conditions - such as a landing impact or a flight through gusts - on various aircraft structures. In order to take those effects into account when pre-designing aircraft it is necessary to study the damping behavior of structures on the material and the component level as well as to establish appropriate decay curves of stress levels and deformations. This approach could be used to improve and partially replace present design criteria based on static loads by more realistic solutions. The assignment of the Institute of Structural Mechanics and Lightweight Design (SLA) is to measure the material damping of specimens made up of aluminium and carbon-fiber-reinforced plastic and to provide data for finite element analyses (FE). Furthermore, experimental modal analyses are carried out on thin-walled stiffened plates and on sandwich panels to investigate the relationship between modal properties and stability behavior of these components. This work is complemented by FE-analyses.
The subproject of the Institute of Structural Mechanics and Lightweight Design (SLA) deals with linked approaches and sensitivity analysis of aerothermoelastic problems in supersonic, especially with the development of an extensive method to optimize aerothermoelastic processes in thrusters. The further develpment of the structure solver ASTRA for anisotropic rotation shells with arbitrary meridian will help to calculate time dependent effects on the structure caused by instationary flows and transient heat flows. Further the methods to improve the thermoelastic calculation of nozzles out of fibre ceramics and nozzles with complex designed walls (for example with cooling channels) are under construction. The collaborative research center Transregio 40 (SFB TR 40) from the German Research Foundation examines the complex interaction problems of highly stressed components in space traveling and is on research in innovative solutions. The target of TR40 is to explore the scientific foundations for extensive improvements in efficiency and reliability of future primary drives in transportation systems for space traveling.