This paper presents a nonlinear model of a clamped-clamped microbeam actuated by an electrostatic load with stretching and thermoelastic effects. The frequency of free vibration is calculated by discretization based on the Differential Quadrature (DQ) Method. The frequency is a complex value due to the thermoelastic effect that dissipates energy. By separating the real and imaginary parts of fr...

In this article, the issue of attitude control and active vibration suppression of a nonlinear flexible spacecraft is assessed through piezoelectric patches as actuator and sensors. Two controller loops are applied: the inner loop, to make the panel vibration damped through piezoelectric patches; and the outer loop, to perform spacecraft maneuver using the reaction wheel acting on the hub. An o...

Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing fau...

Timothy M. Crowder, PhD, is chief technology officer at Oriel Therapeutics, Inc., PO Box 14087, Research Triangle Park, NC 27709, tel. 919.313.1290 ext. 11, fax 919.313.1295, [email protected]. ctive dry-powder inhalers (DPIs) for pulmonary drug delivery have been under development for at least 10 years, but to date no such device has been approved by FDA. Like propellant-driven me...

A noisy autoparametric system exhibiting 1:2 resonance is studied as a random perturbation of a fourdimensional Hamiltonian system. The problem involves three time scales. Nonstandard stochastic averaging technique is rigorously developed, application of which results in a lower-dimensional description of the system. Probability density of the limiting process is obtained using FEM methods. The...

the vibration of cable-stayed bridges subjected to the passage of high-speed trains is studied in this article. the moving train includes a number of wagons, each of which is modeled as a four-axle system possessing 48 degrees of freedom. the car model is nonlinear and three-dimensional and includes nonlinear springs and dampers of primary and secondary suspensions, dry friction between differe...

The simulation results for electromagnetic energy harvesters (EMEHs) under broad band stationary Gaussian random excitations indicate the importance of both a high transformation factor and a high mechanical quality factor to achieve favourable mean power, mean square load voltage, and output spectral density. The optimum load is different for random vibrations and for sinusoidal vibration. Red...

This paper aims at investigating the nonlinear behavior of a system which is consisting of two free-free beams which are connected by a nonlinear joint. The nonlinear system is modelled as an in-extensional beam with Timoshenko beam theory. In addition, large amplitude vibration assumption is taken into account in order to obtain exact results. The nonlinear assumption in the system necessities...