Non-Intrusive Stress Measurement System (NSMS) Sensors with Standoff Capability

Blade tip sensors are increasingly being used to monitor the behavior, diagnose problems and at times aid in predicting the remaining life of bladed disks in gas turbine engines and steam turbines. These sensors are commonly used with a Non-Intrusive Stress Measurement (NSMS) system in the laboratory and in test cells to measure blade resonance (High Cycle Fatigue), detect cracks in blades and disks (Low Cycle Fatigue & High Cycle Fatigue), and detect damage from foreign object impacts. Blade tip sensors are beginning to take the place of strain gages, and also have the potential to move into a real-time monitoring role on-wing. BENEFITS: The use of NSMS as an on-board Prognostics and Health Monitoring system for engine rotor and blades on future aircraft is a topic that is much discussed today. Numerous tests (many with Hood Tech participation) have shown that health indices could be derived and automatically computed and tracked by a digital computer. These tests have also highlighted the fact that fine-tuning of the PHM algorithms is beyond the reach of modeling and that systems will have to be flight tested to complete the development stage of the PHM systems. PHM for rotating engine parts thus enters a new phase: a promising technique 5-10 years ago, it has been proven feasible. It now remains to be done.