Vol.:(0123456789) 1 3 Advanced Composites and Hybrid Materials https://doi.org/10.1007/s42114-020-00200-1 ORIGINAL RESEARCH Structural analysis and wear behavior of diferent graphite‑based brushes for aircraft starter generator application Michael J. Holle 1  · Heath E. Misak 1  · Rizwan A. Malik 2  · Ibrahim M. Alarif 3,4  · Ramazan Asmatulu 1 Received: 14 July 2020 / Revised: 15 November 2020 / Accepted: 19 December 2020 © The Author(s), under exclusive licence to Springer Nature Switzerland AG part of Springer Nature 2021 Abstract This research project focuses on the interrelationship between the rigidity, wear rate, and heat generation of three carbon brushes within a 399-Amp starter generator. The suggested technique is intended to substitute the starter generator with both the starting and generating modes by running each carbon brush in the starter generator for a specifed timeframe and recording the temperature level and extent of wear created. The rationale for conducting the study can be attributed to the case of starter-generator heating through standard usage. Earlier speculation held that the overheating was caused by additional carbon dust that initiated arcing, or secondly, the amount of energy required to form carbon sand liberating an excessively high temperature, which caused a hardening of the brushes. The three brushes selected for this analysis possessed the required rigidity properties necessary for this material type. The research has analyzed the carbon brush surface to coordinate hollows and dents from the frictional coefcient. For this analysis, optical microscopes (AFM and SEM) were used. The fndings imply that as the brushes’ rigidity increased, the wear rate, in turn, reduced, while the whole internal temperature from the starter generator increased. The outcomes suggest that brush stifness is a determining factor in the starter generator’s additional temperature. The energy released in the form of heat as the carbon brushes gradually wear directly corresponds to the operating temperature increase. This implies that enhanced rigidity will extend the brush’s life, while increasing the functional heat to extents that the element cannot handle. Keywords Graphite brushes · Thermal wear · Heat · starter generator · Atomic force microscopy 1 Introduction Most aircraft feature a backup power unit that houses a starter generator. A backup power unit’s essential role is to deliver control to the other aircraft structures prior to the engines igniting. On the other hand, a starter-generator converts electrical energy into a mechanical form, which aids in starting the engine [1–3]. Additionally, the starter generator also turns mechanical energy into an electrical structure that powers the aircraft’s systems [4]. This means that once the engines become ignited, starter generators become the principal source of power for an airplane. However, for applications that do not require extensive power, an APU could be an electrical producer or motorized wind turbine. Brushes utilized in starter generators play a critical role in transferring DC from the stationary kit to the slide rings found in the generator. Interestingly, each time an electric generator is operated, the carbon brushes become exposed to wear, triggered by electrical wear and friction. The current passes through cause’s electrical wear through electrical interaction [5–7]. However, in most applications, the brushes’ life requires optimization since replacing them causes increased operating and maintenance costs, which are both of critical importance to the aviation sector [8–10]. Aircraft equipment manufacturers (OEMs) seek to produce low maintenance and cost-efective * Ibrahim M. Alarif i.alarif@mu.edu.sa * Ramazan Asmatulu ramazan.asmatulu@wichita.edu 1 Department of Mechanical Engineering, Wichita State University, 1845 Fairmount, Wichita, KS 67260, USA 2 Department of Metallurgy and Materials Engineering, University of Engineering and Technology, Taxila, Pakistan 3 Department of Mechanical and Industrial Engineering, College of Engineering, Majmaah University, Al-Majmaah 11952, Maajmah, Kingdom of Saudi Arabia 4 Engineering and Applied Science Research Center, Majmaah University, Al-Majmaah 11952, Riyadh, Saudi Arabia Content courtesy of Springer Nature, terms of use apply. Rights reserved.