نتایج جستجو برای: damping force

تعداد نتایج: 208520  

Journal: :Ultramicroscopy 2007
Shueei Muh Lin

In a common environment of atomic force microscopy (AFM), a damping force occurs between a tip and a sample. The influence of damping on the dynamic response of a cantilever must be significant. Moreover, accurate theory is very helpful for the interpretation of a sample's topography and properties. In this study, the effects of damping and nonlinear interatomic tip-sample forces on the dynamic...

2016
Austin Downey Liang Cao Simon Laflamme Douglas Taylor James Ricles

Implementation of high performance controllable damping devices can ameliorate cost-effectiveness of structural systems for mitigation of natural hazards. However, the applications of these damping systems are limited due to a lack of 1) mechanical robustness; 2) electrical reliability; and 3) large resisting force capability. To broaden the implementation of modern damping systems, a novel sem...

2017

Damping in Dynamic Force Microscopy: The Role of Functionalized Groups. As a relatively new scanning probe technique, Dynamic Force Microscopy [1] has proved to be a powerful tool, allowing for imaging the topography of a sample surface with true atomic resolution. Besides topographic imaging, the simultaneously recorded damping signal is related to non-conservative interaction between tip and ...

1998
S. Davy M. Spajer D. Courjon

The influence of the water layer on the shear force damping is investigated in the case of a perfectly flat mica surface. In ambient conditions it is shown that the damping curve exhibits three particular regimes depending on the tip-sample distance. Moreover, the damping varies significantly over the first hour, pointing out the complexity of the distance control by shear force detection. © 19...

2014
C H Nguyen D S Nguyen E Halvorsen

This paper validates lumped models of an asymmetric bistable MEMS electrostatic energy harvester against measurements. A conventional model of constant damping coe cient turns out to be ine↵ective in predicting or reproducing the device response. This shortcoming is demonstrated by the e↵ective damping coe cient obtained from fits to experimental results being far from constant under varying op...

Journal: :The Journal of the Acoustical Society of America 2010
Dorel Homentcovschi Ronald N Miles

A model of squeeze-film behavior is developed based on Stokes' equations for viscous, compressible isothermal flows. The flow domain is an axisymmetrical, unit cell approximation of a planar, periodic, perforated microstructure. The model is developed for cases when the lubrication approximation cannot be applied. The complex force generated by vibrations of the diaphragm driving the flow has t...

Journal: :Applied Mathematics and Computation 2015
Ninoslav Truhar Zoran Tomljanovic Kresimir Veselic

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...

2014
S. J. Schoonmaker

This paper presents investigations of two special cases of dynamic valve analysis. These special cases arose in the development of a new type of gas field reciprocating compressor. These special cases were for a moving frame of reference (since the discharge valves were integral with the piston) , and for independent mass damping {sealing/damping elements are modelled separately instead of as "...

Journal: :Journal of neurophysiology 2000
D C Lin W Z Rymer

A transient perturbation applied to a limb held in a given posture can induce oscillations. To restore the initial posture, the neuromuscular system must provide damping, which is the dissipation of the mechanical energy imparted by such a perturbation. Despite their importance, damping properties of the neuromuscular system have been poorly characterized. Accordingly, this paper describes the ...

2014
M. Lin L. Sheng Mei Lin

Based on the theoretical analysis and experimental study of pneumatic damping behaviour for the valves in the reciprocating compressor, this paper presents a simple mathematical model of pneumatic damping valves, in which the non-viscous damping force is introduced. The non-viscous damping coefficient is obtained by the experimental determination. The simulation results of this simple model for...

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