guest ::
TY - THES AU - Wegener, Daniel Benjamin TI - Prüfverfahren für Schwingungsdämpfer im Fahrzeug PB - Rheinisch-Westfälische Technische Hochschule Aachen VL - Dissertation CY - Aachen M1 - RWTH-2020-11304 SP - 1 Online-Ressource (175 Seiten) : Illustrationen, Diagramme PY - 2020 N1 - Veröffentlicht auf dem Publikationsserver der RWTH Aachen University 2021 N1 - Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2020 AB - The vibration dampers of a motor vehicle are exposed to high stress during driving operation, which can lead to wear or even complete loss of damping force. In this thesis, test methods are developed which allow a valid, quantitative functional test of the damping in a workshop environment. Important features achieved by the new methods are the evaluation of the damper in an installed condition as well as the fulfilment of objective goals such as validity, accuracy and precision and a high level of expected acceptance by vehicle owners, test authorities and workshop operators. On the basis of theoretical considerations, the damping ratio was derived as a valid parameter for the evaluation of the vibration damper. This required the creation of a model that reduces the total vehicle vibration to a quarter vehicle model. On the basis of this model, the wheel and the body damping ratio can be determined. The admissibility of this model simplification was comprehensively checked. The definition of a vehicle-independent threshold value was derived from the interpretation of the damper conflict diagram. It was shown that, irrespective of the vehicle-specific tuning, a damping ratio of less than 0.1 in the evaluation dimension of driving safety and driving comfort is unreasonable. Using a methodical procedure for system identification, possible excitation types and measurement signals were identified from which a total of five methods for determining the damping ratio were derived. The high measurement effort for the analytical component method, in which all relevant component properties are individually created, leads to a very accurate measurement result that is suitable as a reference value for later evaluation of the workshop measurement method. This can also be illus-trated by the experimental full vehicle method, which requires a complex test bench infrastructure with which the excitation amplitude and frequency can be varied over a wide range. The transient body parameter identification method proved to be advantageous for the workshop area, as it can be implemented cost-effectively, among other things. The additional evaluation of the wheel movement increased the measuring accuracy, especially in the presence of a damper that was only defective on one side. With the transient wheel parameter identification method for the determination of the wheel damping ratio, only low vibration velocities occur with pulsed excitation, which limit the validity. A new evaluation of the widely used EUSAMA method requires an identification of the tire spring stiffness. In spite of the partly limited estima-tion of the tire spring stiffness, this method delivers significantly more precise results compared to the established method. LB - PUB:(DE-HGF)11 DO - DOI:10.18154/RWTH-2020-11304 UR - https://publications.rwth-aachen.de/record/807369 ER -