allow the selection of proper manufacturing such that the manufacturing effort methods based on an even more rational (production time) e.g. for the braiding trade-off between structural process could be reduced by around 50% with only marginal mass penalty. Compari- properties and manufacturing effort. son of results from frames manufactures by and also Hybrid Material Structures Since a basic approach in lightweight ropes in aluminum base material relevant for crash properties structures is to identify and put proper materials to proper components and posi- been investigated in cooperation with tions within a structure, several activities Institutes from KIT and TU Dortmund in have been carried out in this area also in the SFB/TR10 on advanced manufacturing order to identify and reduce possible of processes for such materials. Since such mismatches of the different materials. This parts are mainly aimed for automotive not only relates to their interfaces, but may applications, investigations on crash become also relevant on components and absorption have been finalized end of this structural level. year. These investigations covered related For example, many thermal cycles in materials and components simulations and experimental investigations. Results carbon fiber reinforced materials and parts showed the benefits of such reinforce- may lead to micro-cracks in the polymer, especially so for cycling amplitudes in the ments, which allow to control the crash range of +100°C down to -150°C which is behavior. typical for many structures in space. Due to a softening effect of such micro-cracks, the C-fiber gets even more dominant for the overall properties of the composite. This then results into a further decrease of the coefficient of thermal expansion, which could change from say -0.2 E-6 / °K down to -1 E-6 / °K. Though still very small in absolute terms, this large relative change might become relevant for structural thermo-elastic deformations and related loss of geometric precision in orbit. Steel fiber reinforced aluminum parts have Simulated and tested behavior of steel
such that the manufacturing effort (production time) e.g. for the braiding process could be reduced by around 50% with only marginal mass penalty. Compari- son of results from frames manufactures by and also allow the selection of proper manufacturing methods based on an even more rational trade-off between structural properties and manufacturing effort. Hybrid Material Structures Since a basic approach in lightweight structures is to identify and put proper materials to proper components and posi- tions within a structure, several activities have been carried out in this area also in order to identify and reduce possible of mismatches of the different materials. This not only relates to their interfaces, but may become also relevant on components and structural level. For example, many thermal cycles in carbon fiber reinforced materials and parts may lead to micro-cracks in the polymer, especially so for cycling amplitudes in the range of +100°C down to -150°C which is typical for many structures in space. Due to a softening effect of such micro-cracks, the C-fiber gets even more dominant for the overall properties of the composite. This then results into a further decrease of the coefficient of thermal expansion, which could change from say -0.2 E-6 / °K down to -1 E-6 / °K. Though still very small in absolute terms, this large relative change might become relevant for structural thermo-elastic deformations and related loss of geometric precision in orbit. Steel fiber reinforced aluminum parts have Simulated and tested behavior of steel ropes in aluminum base material relevant for crash properties been investigated in cooperation with Institutes from KIT and TU Dortmund in the SFB/TR10 on advanced manufacturing processes for such materials. Since such parts are mainly aimed for automotive applications, investigations on crash absorption have been finalized end of this year. These investigations covered related materials and components simulations and experimental investigations. Results showed the benefits of such reinforce- ments, which allow to control the crash behavior.
02-Baier-Institute_of_Lightweight_Structures-2015.docx