Andreas Eder

The measurement of acoustic emission data in experiments reveals informative details about the tribological contact. The required recording rate for conclusive datasets ranges up to several megahertz. Typically, this results in very large datasets for long-term measurements. This in return has the consequence, that acoustic emissions are mostly acquired at predefined cyclic time intervals, which leads to many blind spots. The following work shows methods for effective postprocessing and a feature based data acquisition method. Additionally, a two stage wear mechanism for bearings was found by the described method and could be substantiated by a numerical simulation.

The main objective of the present paper is the validation of new methods concerning experimental investigations of journal bearings under ordinary and extraordinary operational conditions. Derived results should facilitate the determination of damage mechanisms and a qualitative ranking for a prospective coating development. Prior investigated scenarios like start/stop and emergency running behavior were extended by starved and unlubricated experiments for an aircraft application. Focusing on thermal stability and reproducibility, two new subscale test strategies were developed derived from generalized operational conditions of journal bearings. For an improved ex-situ wear measurement of bearing shells, a new device was developed successfully. The results showed that the newly designed test methodologies are suitable to investigate unlubricated coatings leading to conclusive and repetitive results.