Comparison of On-Bearing and On-Casing Vibration for Blade Health Monitoring in Rotating Machine

Rotating blades are considered as the most common cause of failures in rotating machinery. In the present research study, the dynamics of the blades both in the healthy and crack conditions are studies on a small experimental rig using the on-bearing and on-casing vibration, which are measured using the accelerometer on bearing pedestals and on casing cover towards on blades. The measured vibration data are analyzed by computing the responses at different engine orders (EOs) related to the blade resonance frequencies and their higher harmonics to understand the blade(s) dynamics behavior. The observations suggest that the on-bearing and on-casing vibration measurements can be extended to the non-intrusive method for the blade health monitoring (BHM). Comparative study between the on-bearing and on-casing vibrations on the simple experimental rig further allow to understand which method is more effective for blade damage detection.