Helicopter rotor aeroelastic analysis using a refined elastomeric damper model

A new nonlinear time domain model for rotorcraft elastomeric dampers is developed. Previous state-of-the-art damper modeling approaches are reviewed and discussed in terms of their advantages and disadvantages. A nonlinear elastomeric material model is developed, characterized and validated against time-domain material coupon experimental data. The material model is written in finite element form and coupled to rotor system equations of motion as an elastomeric damper component model. Combined rotor-damper modeling issues are discussed and results are presented. Results include studies of system steady state response, stability, and time domain damper loads. Time domain cases are of particular interest because previous modeling approaches were shown to be inaccurate for predicting damper peak loads for certain cases. The new damper model, along with a nonlinear kinematics model, is used to study rotors with interblade dampers. These rotors have dampers connected from blade to blade rather than blade to hub in the traditional configuration. Experimentally observed behavior of these rotors is predicted by the new modeling approach. Previous interblade damper modeling approaches do not predict such behavior.