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Abstract. Compound extruded unidirectionally reinforced profiles are heterogeneously reinforced metal matrix composites. Profiles made from this material show a different mechanical behaviour than classical composite components. Homogenized material properties are required for an efficient design process. Within this paper an approach is shown to provide homogenized data for stiffness and strength for compound-extruded components. The usability of the Tsai-Hill failure criterion is investigated, and shown for cases with negligible residual stresses. Load cases including thermal stresses cannot be investigated by the TsaiHill failure criterion. Within the failure investigation a procedure is shown to include residual and thermal stresses.

Metal matrix composites offer a very good performance in a wide temperature range, but are limited to few applications due to high production costs. A novel compound extrusion process developed within the collaborative research centre SFB/TR 10, supported by the German Research Foundation (DFG -Deutsche Forschungsgemein-schaft), provides an economical production method for reinforced aluminium profiles. Using different reinforcement fractions it is possible to increase the strength of these components locally and to reduce the macroscopic coefficient of thermal expansion (CTE) and thus to tailor mechanical as well as thermal properties. For application in frame struc-tures, an efficient approach for sizing these properties is necessary, especially in regions with a 3D stress state. There-fore an approach is shown based on data gained analytically and with numerical analyses, allowing a dimensioning of cross sections required. The applicability of this approach is shown using a finite element (FE) model of a bent rein-forced aluminium profile. To verify the failure of the profile an own developed failure criterion was applied which is based on a test program, including classical tensile tests in direction of extrusion and perpendicular to it. Furthermore the process of biaxial testing of extruded profiles with small dimensions is shown.

Engineering information is often uncertain, deviated, imperfect, erroneous, imprecise, etc. Fuzzy methods, based on possibility theory are well suited for describing epistemic uncertainty. Included in epistemic uncertainty are data sets where only few samples are available and are appropriately modeled with fuzzy methods. The resulting fuzzy parameters can then be used in structural analysis, allowing for nondeterministic consideration and, therefore, uncertainty assessment. In this study, different approaches to construct fuzzy membership functions are discussed and compared. Further, the influence of fuzzy modeling, or fuzzification, is evaluated within the framework of structural analysis and then in the safety factor assessment. The mechanical response was calculated using finite element analysis with uncertain material, evaluating stress and buckling load factor. Finally, the fuzzy safety factors were quantified for the different fuzzification methods, showing the importance of uncertainty consideration.

With the market introduction of the EC135 the bearingless main rotor (BMR) as a novel main rotor system was put into series production. Since then a chain of interconnected research programs led to the next generation of BMR. It now enhances the qualities of the H145 regarding the aspects of useful load, comfort of ride, purchase and maintenance cost as well as operational features. The design targets definition and their implementation by innovative solutions are summarized hereafter. The focus is put on the modular design of the main rotor system which is realized by an integrated flexbeam and control cuff assembly and a separate rotor blade joined together by a bolted connection using flat laminate lay-up instead of fiber loops. A detailed view is given on the development of the novel blade attachment from design considerations and manufacturing aspects over parametric subcomponent tests to full scale testing.