Nonlinear dynamics and stability analysis of dry friction damper for supercritical transmission shaft

Supercritical transmission shafts—those which have one or more critical speeds below their operation speeds—are becoming more popular in new armored vehicle and rotorcraft designs. To suppress the excessive transcritical vibration, dry friction damper is a prevailing choice. In this paper, we focus on the nonlinear dynamics, stability and bifurcation mechanism of the dry friction damper for supercritical transmission shaft. The harmonic balance method with alternating frequency-/time-domain technique (HB-AFT) and the numerical path continuation is employed to solve the nonlinear governing equations of the shaft/damper system where the rub-impact and dry friction phenomena are involved. The stability and bifurcation points of the solution branch are further determined with the help of Floquet theory. Besides, the effects of three damper parameters, that is, the clearance, the critical slip force and the circumferential friction coefficient, are investigated. Finally, prototypes of the dry friction damper are designed, manufactured and tested on a high-speed rotor dynamics test rig. The theoretical findings are in general agreement with the experimental results.