EXPERIMENTAL INVESTIGATION OF AS-MANUFACTURED MODELING FOR INTEGRALLY BLADED ROTOR FREQUENCIES AND MODE SHAPES

Abstract

This work experimentally measures an academic rotor's mistuned system and blade-alone vibration behavior while validating an as-manufactured finite element modeling process. The model is created using blade geometry deviations captured with a structured light measurement system and a target-surface mesh morphing process. Geometry measurement uncertainty is established through repeated scans, and an uncertainty metric is used to ensure accuracy. Experimental vibration data for the academic rotor are acquired using a traveling-wave excitation system and a scanning laser vibrometer. A dense measurement grid provides a detailed characterization of blade mode shapes up to 10~kHz. Isolated blade-alone vibration data is collected to validate the mistuned system identification of the traveling wave data and for comparison with the as-manufactured model. The results show excellent correlation between the analytical model predictions and experimentally obtained measurements for modes in the wide frequency range, while also discovering significant blade mode shape variations at closely spaced mode families. The models' validity in this sensitive nonlinear region gives additional confidence in their use for mistuning analysis and experimental planning in turbomachinery applications.