Abstract:
A physics-based, fully nonlinear hydraulic damper model was developed within the framework of the Rotorcraft Comprehensive Analysis System (RCAS) in order to facilitate integrated damper and rotorcraft analysis and design. The hydraulic damper governing equations of motion were formulated using flow continuity equations for each hydraulic device within the damper. The developed damper model was evaluated for an integrated rotor-damper solution and was verified against test data from the NASA-Army UH-60A Airloads Program. For these evaluations, the accuracy of blade load predictions using the developed damper was compared against conventional linear and nonlinear (table lookup) damper models. From these comparisons, the developed damper model is shown to better capture the isolated damper dynamics. The assessment help address the previously identified issues and uncertainties and identify trends or dependencies.