Aero-Engine Compressor Bladed Disk Vibration Measurement Using Blade Tip Timing and Laser Doppler Vibrometry

Ensuring the structural integrity and operational reliability of aero-engine compressors requires precise vibration measurement of rotating blades. Blade tip timing (BTT) is a widely used noncontact measurement technique, but its accuracy is inherently influenced by the blade’s twisted geometry and probe positioning. This study introduces a calibration framework that improves BTT precision by integrating finite element (FE) modeling to account for blade geometry and vibration characteristics. By extracting vibration mode shapes from the FE model and converting them into an equivalent measurement plane, this method enhances the reliability of BTT measurements. The calibration is validated using laser Doppler vibrometry (LDV), which serves as a high-precision reference in controlled laboratory conditions. Results show that this approach significantly reduces measurement discrepancies from 10% to a range of 2%–3%, strengthening BTT’s robustness in industrial applications where LDV is not deployable. In addition, the study establishes a crucial restriction on sensor positioning near the blade tip, identifying areas where BTT probes may fail to capture meaningful data depending on the mode shape. This work lays the foundation for standardized calibration methodologies in turbomachinery health monitoring, ultimately improving predictive maintenance strategies and diagnostics.