MODAL ANALYSIS OF MICROCANTILEVER SENSORS WITH ENVIRONMENTAL DAMPING

The vibration response of microcantilevers to simple harmonic base motion is formulated in terms of base motion plus modal responses relative to the moving base frame. Environmental damping is evaluated. The analysis gives the frequency responses of the first four modes and shows that the phase angle of each mode relative to the moving base frame is constant but that the phase angle of the absolute motion varies along the length of cantilevers. This finding is verified with experimental data. Phase changes along cantilevers depend on frequency ratios and the magnitude of environmental damping. Experimental data are used to establish damping factors, and phase angles are measured experimentally and compared with theoretical predictions. (C) 2005 American Institute of Physics.open112537sciescopu

Transient mixed non-Newtonian thermo-elastohydrodynamics of vehicle differential hypoid gears with starved partial counter-flow inlet boundary

The paper presents solutions for transient mixed thermo-elastohydrodynamics of meshing differential hypoid gears of a vehicle under low speed urban driving and high speed cruising. Realistic gear meshing conditions, such as contact load including inertial effects are used, in line with engine power torque and wheel traction. This constitutes simultaneous solution of gear pair dynamics, non-Newtonian elastohydrodynamics as well as vehicle longitudinal inertial dynamics, an approach not hitherto reported in the literature. The important link between contact tribology and vehicle gearing dynamics is highlighted. It is also shown that gear teeth pairs are subjected to a starved inlet boundary condition, represented by realistic inlet flow analysis. These conditions lead to the formation of a thin lubricant film with non-Newtonian shear and with modest boundary interactions