Thermo-mechanical Characterization and Analysis of the H-60 Lag Damper

The performance and characteristics of a full-scale H-60 hydraulic lag damper are investigated as a function of operating and environmental temperatures. Two full-scale hydraulic lag dampers were tested on an MTS servo-hydraulic testing machine in the Composites Research Laboratory of the Alfred Gessow Rotorcraft Center. The first was a damper with many flight hours, and the second was a new damper. Testing was performed under single frequency (lag mode frequency and rotor frequency) sinusoidal excitations at temperatures varying from -40 to +160°F. A hydro-mechanical analysis was then developed to predict the behavior of the hydraulic lag damper, and the analysis validated using experimentally measured data.