The Load Confluence Algorithm Applied to a Combined Rotor/Fuselage Loads Model with Extended Application to Structural Fatigue Life Tracking

This paper presents research addressing the technological gap in the predictive capabilities of modern computational fluid-structures interaction (FSI) in the context of the US Navy's requirement for accurate loads prediction for both critical rotorhead and fuselage components in the context of a real aircraft’s fatigue life tracking program, with the ultimate objective of loads accuracy and performance robust enough to support near real-time lifing assessments across the full flight regime. This research, funded via US Navy STTR N17A-T009, touches on a broad range of innovative research areas, starting with application of the Load Confluence Algorithm (LCA) to a coupled main rotor-fuselage/tail rotor model for the UH-60A. This paper will document research to date, extending beyond traditional approaches such as the main rotor analyzed in isolation or a fuselage model affected only by the inflow generated via an actuator disk model of the main rotor. This includes the development of use of modal super- elements (MSEs) to model more complex rotorcraft components, such as the fuselage for use in main rotor loads simulations, as well as the stationary and rotating swashplates, and the rotating scissors. This paper will also document advances made in geometry modeling and mesh generation, computational mechanics of fluids and structures, modeling of coupled multi-physics phenomena, and high-performance computing, with improved representation of complex geometry and multi-physics phenomena. Lastly, these enhanced whole aircraft loads prediction methods will be examined within the context of future application to a structural fatigue life tracking program, in terms of accuracy, usability, and application performance.