Purpose: The aim of this paper is to identify the root cause of the temporary decrease of the damping force during the early stage of the compression phase of the stroking cycle, the so called damping lag, to describe measures of the phenomenon and to present methods for optimizing the design towards minimizing this (negative) effect. Design/methodology/approach: Theoretical background is prese...

DAMPING Rakesh K. Goel SUMMARY This study investigated the effects of neglecting off-diagonal terms of the transformed damping matrix on the seismic response of non-proportionally damped asymmetric-plan systems with the specific aim of identifying the range of system parameters for which this simplification can be used without introducing significant errors in the response. For this purpose, a ...

An L1 norm minimization scheme is applied to the determination of the impulse response vector h of flaws detected in practical examples of ultrasonic nondestructive evaluation in CANDU nuclear reactors. For each problem, parametric programming is applied to find the optimum value of the damping parameter that will yield the best estimate of h according to a quantified performance factor. This p...

The on-line or adaptive identification of parameters in abstract linear and nonlinear infinite-dimensional dynamical systems is considered. An estimator in the form of an infinitedimensional linear evolution system having the state and parameter estimates as its states is defined. Convergence of the state estimator is established via a Lyapunov estimate. The finite-dimensional notion of a plant...

Geophysical down-hole surveys can be used to measure the small strain dynamic properties of soils by the effects these properties have on wave propagation. The relevant effects include amplitude decay (corrected for beam divergence) and velocity dispersion. In this paper, down-hole data collected during the GeoInstitute's Denver 2000 field day are presented and analyzed as a Kelvin-Voigt solid....

We consider a mechanical system excited by an external force. Model of such a system is described by the system of ordinary differential equations: Mẍ(t) + D(v)ẋ(t) + Kx(t) = f̂(t), where matrices M,K (mass and stiffness) are positive definite and the vector f̂ corresponds to an external force. The damping matrix D(v) is a positive semidefinite matrix which depends on damping positions and parame...

Non-linear vibration of the CRT shadow mask with impact damping wires is analyzed in consideration of the mask tension distribution and the effect of wire impact damping. A reduced order FEM model of the shadow mask is obtained from dynamic condensation of the mass and stiffness matrices, and damping wire is modelled using the lumped parameter method to effectively describe its contact interact...

Dispersion relations of longitudinal and transverse waves in two-dimensional (2D) screened-Coulomb crystals were investigated. The waves were excited in 2D crystals made from complex plasmas, i.e., dusty plasmas, by applying radiation pressure of laser light. The dependencies of the dispersion relation on the shielding parameter, the damping rate, and the wave propagation direction were experim...

Affinity propagation clustering (AP) has two limitations: it is hard to know what value of parameter ‘preference’ can yield an optimal clustering solution, and oscillations cannot be eliminated automatically if occur. The adaptive AP method is proposed to overcome these limitations, including adaptive scanning of preferences to search space of the number of clusters for finding the optimal clus...

Abstract Rectification of tilting ratchets is investigated, going beyond the well-studied over-damped regime. The negative friction Langevin dynamics technique is employed to evaluate rectification coefficient such as that for the d.c. voltage of a SQUID rocking ratchet. Numerical results for rectification coefficient in a wide range of temperatures show that variation in the value of damping p...