A technique for noninterference measurement of turbine engine rotor blade stresses is being developed as an alternative to conventional straingage measurement systems. The noninterference blade stress measurement technique uses optical sensors mounted on the periphery of the rotor stage to measure blade passing events to determine blade-tip deflections. Blade vibratory stresses are inferred by using blade-tip deflection to stress conversion algorithms. This paper summarizes the results of tests to evaluate the performance of line-focus blade-tip sensors and demonstrates the recently developed stress conversion algorithms. The tests were conducted in an evacuated spin rig using a turbine engine first-stage fan having all blades instrumented with piezoelectric crystals to excite the blades in controlled vibration patterns and strain gages to measure the response. Four blade-tip sensors were circumferentially aligned along the path of the rotating blades. Each sensor received light from an argon laser and projected a narrow plane of light normal to the blade path. The sensor signals were evaluated for sensitivity, resolution, and rise time. Dynamic strain data from the noninterference measurements were compared to the strain-gage results for three modal families.
Demonstration testing of a noninterference technique for measuring turbine engine rotor blade stresses
Vorfuehrtest einer Nichtinterferenz-Methode zur Messung von Spannungen in Turbinenschaufeln
AIAA-Papers ; Jul ; 1-7
1988
7 Seiten, 12 Bilder, 14 Quellen
Conference paper
English