Elastomeric Dampers derived from First-Principles-Based Analytical Simulation

Lead-lag motions of rotor blades in helicopters require damping to stabilize them. In practice, this has necessitated the use of external hydraulic dampers which suffer from high maintenance costs. High operational (lifecycle) cost has prompted rotorcraft industry to use elastomeric lead-lag dampers that result in "dry'' rotors. However, complex behavior of elastomers provides challenges for modeling such devices, as noted by rotorcraft airframers. Currently used analytical models oversimplify the complexity of operational environment and make radical assumptions about operating parameters that, at best, lead to excessively simplistic, and often unreal, device models. These first order linear device models require costly and time consuming experiments to construct them; moreover, they do not directly relate to either the material characteristics or the geometric configuration. In Phase-I SBIR, MTC team pursued a fundamentally radical approach wherein elastomeric dampers are derived from first-principle-based modeling rather than device model-based analyses. Our Phase-I program was tailored towards successfully demonstrating closed loop simulation, i.e. a finite element based modeling of elastomeric materials integrated into a multibody dynamics framework for rotorcraft analysis. During Phase-II, comprehensive and sophisticated material models will be implemented and streamlined into a single comprehensive analysis framework. These implementations will be fully validated against bench and flight test data of Bell M429 elastomeric dampers. These program objectives will be accomplished via collaborative tripartite partnership with Bell Helicopter and Georgia Tech.