High-speed camera-based optical measurement methods for in-mesh tooth deflection analysis of thermoplastic spur gears

Abstract

The engineering characteristics of polymer gears, such as wear and fatigue resistance, are dictated by the underlying processes that take place during the gear meshing phase. These are in turn dependent on the running load, speed, temperature, lubrication regime and other parameters. So far, the structural response of a meshing gear could only be analysed using numerical approaches, typically involving the finite element method. In this study, an optical experimental analysis approach is proposed to evaluate the in-mesh gear tooth deflection based on high-speed camera recordings. For this purpose, two image processing methods were implemented, namely the well-known Digital image correlation method and a newly proposed Edge displacement detection method. Using an experimental setup with a camera resolution of 1024×1024px, an exposure time of 40 μs, a frame rate of 2·104fps and a 2000 lm focused light source, a measurement accuracy of ±5μm could be achieved. A good correlation between both methods and finite element analysis results was confirmed. Furthermore, the newly proposed Edge displacement detection method offers high potential for experimental analysis of long-term wear and strain accumulation processes.