Effect of gear tooth root crack on the dynamic response of a planetary geared rotor system

This research presented a dynamic model of a planetary geared rotor system and investigated the influence of tooth root cracks on the system’s response. The rotor components were modeled using the finite element method, while the planetary gearbox members were modeled with the lumped parameter method. The model assumed a non-rotating planetary carrier and planet gears equally spaced. Different parameters were considered for cracks at the tooth root of the ring, sun, and first planet gears. The system’s response was analyzed by comparing the frequency domain acceleration response, the acceleration signal’s power spectrum, and the intrinsic mode functions obtained via empirical mode decomposition of the acceleration signal for the healthy and cracked system. Results indicated that crack size is the most significant parameter in altering the system’s response. The signal’s power spectrum enabled clear crack detection, size differentiation, and identification of the affected gear. The empirical mode decomposition of the acceleration signal proved to be particularly advantageous in distinguishing between crack sizes in higher frequency ranges, with the first intrinsic mode function showing significant differences depending on the crack size.