In this paper we present a 3D nonlinear dynamic model which describes the transient mechanical analysis of an ohmic contact RF MEMS switch, using finite element analysis in combination with the finite difference method. The model includes real switch geometry, electrostatic actuation, the two-dimensional non-uniform squeeze-film damping effect, the adherence force, and a nonlinear spring to mod...

This paper describes a design approach to Lorentz motors that serve as active damping component applicable in dynamic vibration isolators used for integrated circuit(IC) equipments. To satisfy the demand of high force density in constrained space and high current accuracy of motor drive for active damping, an analytical layer model with proper simplifications is employed to get preliminary dime...

Numerous dynamic atomic force microscopy (AFM) methods have appeared in recent years, which make use of the excitation and detection of higher order eigenmodes of the microcantilever. The ability to control these modes and their responses to excitation is believed to be the key to unraveling the true potential of these methods. In this paper, we highlight a multimode Q control method that exhib...

1. Theory An earlier treatment of line broadening in vibrational bands due to chemical exchange [2] was based on a second order perturbation theory. It dflers already for the case of non-exchanging systems from the density matrix procedure given by [1,3], although in this case the finite results are identical. To clear the issue it may prove helpful to derive the relevant equations using a pure...

A biased electrode is used in the Madison Symmetric Torus ~MST! reversed-field pinch @Fusion Technol. 19, 131 ~1991!# to manipulate plasma flow in order to study flow damping and momentum transport. Finite radial conductivity allows a radial current, which provides the toroidal torque that spins up the plasma. The applied torque is balanced by a viscous force that opposes toroidal flow accelera...

In this paper, a fundamental solution for the Mindlin plate theory with damping is derived in the Laplace transform domain first time. The applications of this fundamental solution are demonstrated by the method of fundamental solution (MFS). All variables in the time domain can be obtained by the Durbin’s Laplace transform inversion method. Numerical examples demonstrate the accuracy of the me...

A method of estimating damping parameters for multidegree-of-freedom vibration systems is outlined, involving a balance of dissipated and supplied energies over a cycle of periodic vibration. The power is formulated as the inner product between velocity and force terms, and integrated over a cycle. Conservative terms (mass and stiffness) drop out of the formulation. The displacement response an...

In this paper, the advantage of an adaptive damping system is presented. A damper with variable stiffness is tuned based on estimates of the real-time frequency response, facilitating optimal vibration mitigation. The performance of the developed routines is investigated on an existing tied arch railway bridge. Based on previous field measurements, resonant behaviour of several hangers was foun...

The present work demonstrates the successful application of a simple active vibration control procedure based on structural dynamics. Based on mathematical and structural dynamics’ theories, the appropriate locations of sensor and actuator locations of the smart structure are predicted. Also, the optimum value of actuator force which controls the structural vibrations as quickly as it is possib...

The accelerating fields (e. g. centrifugal acceleration and constant acceleration) can change the physical performance of nano-sensors significantly. Herein, a new size-dependent model is developed to investigate the scale-dependent dynamic behavior of nanowire-fabricated sensor operated in an accelerating field. The scale-dependent equation of motion is developed by employing a consolidation o...