Friction in joints significantly contributes to the observed overall damping of mechanical structures. Especially if the material damping is low, the frictional effects in joints and clamping boundary conditions dominate the structural damping. The damping and the stiffness of the structure are nonlinear functions of the system states and consequently of the excitation signal and amplitude. If ...

We study the effects of temperature and sliding velocity on superlubricity in numerical simulations of the Frenkel-Kontorova model. We show that resonant excitations of the phonons in an incommensurate sliding body lead to an effective friction and to thermal equilibrium with energy distributed over the internal degrees of freedom. For finite temperature, the effective friction can be described...

We investigate the role weakly damped modes play in the selection of Faraday wave patterns forced with rationally-related frequency components mω and nω. We use symmetry considerations to argue for the special importance of the weakly damped modes oscillating with twice the frequency of the critical mode, and those oscillating primarily with the “difference frequency” |n − m|ω and the “sum freq...

in this paper, a novel compensator based on magnetically controlled reactor with fixed capacitor banks (fc-mcr) is introduced and then power system stability in presence of this compensator is studied using an intelligent control method. the problem of robust fc-mcr-based damping controller design is formulated as a multi-objective optimization problem. the multi-objective problem is concocted ...

Silicon-MEMS gyroscope is an important part of MEMS ( Micro Electrical Mechanical System). There are some disturb ignored in traditional gyroscope that must be evaluated newly because of its smaller size (reach the level of micron). In these disturb, the air pressure largely influences the performance of the MEMS gyroscope. Different air pressure causes different gas damping coefficient for the...

a r t i c l e i n f o a b s t r a c t A shunted piezoelectric is a device to suppress vibration consisting of a piezoelectric material and a shunt circuit connecting between two electrodes of the piezoelectric material. The sensitivity of damping performances is analyzed for passive shunted piezoelectrics: a resistive, a series resonant, and a parallel resonant shunted piezoelectric. The parame...

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We consider dissipative one-dimensional systems subject to a periodic force and study numerically how a time-varying friction affects the dynamics. As a model system, particularly suited for numerical analysis, we investigate the driven cubic oscillator in the presence of friction. We find that, if the damping coefficient increases in time up to a final constant value, then the basins of attrac...