Combined Analytical and Experimental Approaches to Rotor and Dynamic Component Stress Predictions

The objective of rotorwise™ is to provide better loads prediction for rotor components, leading to more accurate, more reliable fatigue life predictions and fleet management. rotorwise™ works as follows. In the modal domain, changes in the applied loads are related to changes in measured response (e.g., acceleration or strain). The solution is then iterated until a best fit match between analytically-predicted and measured strains is reached (by harmonic) at predefined control points. Predicted loads response at non-instrumented locations is improved as well, thus enhancing fatigue lifing methods for these components. This technology is being extended in support of PMA-261 and AIR-4.3.3.5 in support of further research and development for application to the CH-53K for use in the Integrated Hybrid Structural Management System (IHSMS). This technology supports the US Navy’s end goal of tracking rotorcraft life in near real-time, gathering complete component loads/usage history and thereby accurately predicting the life of each system, subsequently eliminating penalties imposed due to unknown usage histories and/or inaccurate/overly-conservative loads prediction. The strategy detailed herein supports this end goal by combining analytical modeling and experimental data to dramatically improve the accuracy of predictions for individual blade loads and stresses in dynamic components.