High Fidelity Helicopter Lag Damper Model for Comprehensive Rotor Analysis

The primary goal of this STTR program is to develop high fidelity LDLP software module that can predict stiffness and damping forces over the ranges of amplitude, frequency, and temperature appropriate for comprehensive modeling of helicopters. The LDLP module will focus on enabling accurate prediction of the onset of both air and ground resonance, as well as the fatigue loads that would arise due to the implementation of such lag dampers, and the impact of fatigue on the Remaining Useful Life (RUL) of rotor and rotor hub components. This project will develop a software module that provides the capability to predict lag damper behavior, especially the stiffness and damping forces that arise from lag dampers of varying configuration, material choices, fluid properties, and feedback control strategies in the case of semi-active or active lag damper technologies. The project team will construct an LDLP software module that will be configured to interface with any existing comprehensive rotorcraft analysis code, such as the University of Maryland Advanced rotorcraft Code (UMARC), Copter (Bells comprehensive rotor code), CAMRAD II (Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics), and GenHel (Sikorskys General Helicopter Flight Dynamic Simulation Model).