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

Recent studies have made an attempt to couple computational structural dynamic tools with sophisticated computational fluid dynamic (CFD) solvers. The CFD approach is still at a nascent stage and discrepancies can be observed in both phase and amplitude of the predicted load. Due to the inefficiencies of the currently available aerodynamic models, load predictions will have to rely on experimentally measured aerodynamic loads. Therefore, a coupled approach involving both an analytical methodology for structural analysis and experimentally measured aerodynamic loads should be employed to predict individual component loads as well as the stress and strain field in critical locations. These results can then be utilized for damage tolerance and failure prediction of the individual components. The structural model should not only be able to capture the dynamic load experienced by components such as the pitch link, swashplate, hub or trailing edge flap but also detailed stress and strain field in each ply of the composite blade. Therefore, a validated three- dimensional analysis capability is required for structural dynamic analysis of rotor blades to make accurate load and stress predictions. For this purpose, Global Engineering and Research Technologies will improve and validate an existing in-house code.