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Blisk fatigue blade failure4/6/2023 ![]() ![]() Within the proposed method, a BLISK is assessed for the most severe loading condition considering HCF load by a modified Goodman method, along with a Coffin-Manson based approach for LCF contribution. To forecast the turbine blade fatigue life, analytical (0-D) and numerical approaches for a selected test case are studied. Therefore, in addition to bending & torsion as well as thermal gradient and centrifugal forces, it is critical to consider creep effects in durability studies. Turbine blades are exposed to large thermo-mechanical cyclic strains emerging from an increased temperature driving gas combined with a fast start-up sequence as well as a large rotational speed – essential for acquiring high performance and structural mass efficiency for LREs. ![]() Validation of defined applied analytical and numerical techniques is established through the Liquid Upper stage deMonstrator ENgine (LUMEN)’s, developed at DLR Lamplodshausen for enhanced expertise in the complete cycle operation for various engine applications, as well as to empower validation studies of the operational conditions to which turbopump components, such as turbine blades, are subjected. Therefore, within our research we focus on the turbine blade investigation for reusable LRE applications including high cycle fatigue (HCF) and low cycle fatigue (LCF). To enable further expansion and cost-effectiveness of the reusability technology for future liquid rocket engines (LREs), research on critical engine components such as turbopumps is crucial. We identify sets of optimal suited patch geometries in accordance to the specified damage pattern.Abstract-Reusability of LREs in Europe is increasingly attracting the attention of scientific community and industry with leading projects such as THEMIS, CALLISTO (reusable demonstrators for vertical take-off and landing (VTVL)) and Ariane Next – all powered by the reusable cryogenic Oxygen/Methane (LOX/LCH4) engine “Prometheus”. The application of the new approach to a compressor blisk demonstrates the influence of vibration modes on fatigue strength. The engineer’s decision for a specific patch geometry can thus be made based on the optimisation results. Pareto-optimal solutions are calculated using a generalised pattern search algorithm. The fatigue strength and the length of the welding seam are defined as conflicting targets. On the basis of this automated process, a multi-objective optimisation is carried out. High cycle fatigue is assessed for welding seam positions specified by the patch model. ![]() A fully parameterised patch model is developed, which allows the accurate description of the patch geometry. In this work, we contribute to the structural design of patches for compressor blisks with improved high cycle fatigue behaviour. Patching is a high-tech approach towards reduced scrap rates and an extended life of high pressure compressor blisks.
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