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TY - THES AU - Zalfen, Moritz Johannes TI - Einfluss der Dehnrate auf die Zahnfußtragfähigkeit schnelllaufender Zahnradgetriebe; 1. Auflage VL - 2025,18 PB - Rheinisch-Westfälische Technische Hochschule Aachen VL - Dissertation CY - Aachen M1 - RWTH-2025-09491 SN - 978-3-98555-308-2 T2 - Ergebnisse aus der Produktionstechnik SP - 1 Online-Ressource : Illustrationen PY - 2025 N1 - Druckausgabe: 2025. - Auch veröffentlicht auf dem Publikationsserver der RWTH Aachen University N1 - Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2025 AB - The tooth root strength is a basic requirement for the safe operation of a gearbox, as a tooth root fracture usually leads to total failure. Current efforts to reduce the effects of global climate change require the optimization of power density in order to reduce the resources required for the production and operation of gearboxes. As a result, the operating speeds are being increased or the operating time extended. As a result, the required service life for the gear design often exceeds the limit load cycles of N_G = 10^9 to 10^10 load cycles. Previous design parameters are generally limited to a limit load cycle number of N_G = 10^7 load cycles and are extrapolated using statistical assumptions or safety factors. The extension of the material characteristics to the VHCF and UHCF range with a comparable test duration requires the development of test rigs with higher speeds or test frequencies. The influence of the speed or strain rate on the tooth root strength must be known and taken into account. The aim of the present work was to develop a validated method for calculating the local and temporal stress as well as the strain rate in the tooth root for high-speed drive trains. The originality of the method lies in the transfer of the tooth contact analysis into the time domain to calculate the strain rate in the tooth root, taking into account additional dynamic loads and the quantification of the influence of the strain rate on the tooth root strength of case-hardened gears. The economic and technical relevance lies in the construction of a high-speed test rig for the efficient investigation of the tooth root strength in the VHCF range and at high speeds. Based on the results, a concept of an analogy test for the realization of application-related strain rates was evaluated. The research objective was achieved by validating the calculated tooth root stress in the time domain with strain gauge measurements during operation. Based on the method, a simplified procedure for estimating the strain rate in the tooth root was developed and the strain rates on gears were categorized in the state of the art for the first time. Consequently, an influence of the strain rate can be expected in current and future gear applications. Based on this, a high-speed test rig was developed, constructed and put into operation, which enables the investigation of the tooth root strength at n_1 = 12000 1/min. Tests were carried out on tooth root strength in the VHCF range at n_1 = 3000 1/min and n_1 = 12000 1/min for different hardening depth conditions. The comparison of the tooth root strength shows that the strain rate has a significant influence on the strength and the critical damage type depending on the hardness. The feasibility assessment of an analogy test for testing realistic strain rates in the tooth root shows that today's universal testing machines cannot achieve the necessary test frequencies. Accordingly, the investigation is currently only possible in a running test. LB - PUB:(DE-HGF)11 ; PUB:(DE-HGF)3 DO - DOI:10.18154/RWTH-2025-09491 UR - https://publications.rwth-aachen.de/record/1021138 ER -