Mechanics
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ISSN 1734-8927
e-ISSN: 2300-7060
Issue Date
2007
Volume
Vol. 26
Number
No. 4
Description
Journal Volume
Mechanics
Vol. 26 (2007)
Projects
Pages
Articles
Analysis of the dependence between a temperature and working parameters of the MR damper
(Wydawnictwa AGH, 2007) Bajkowski, Jerzy; Bajkowski, Marcin; Grzesikiewicz, Wiesław; Sofonea, Mircea; Shillor, Meir; Zalewski, Robert
In this paper detailed description of temperature influence on MR damper working parameters has been described. Prototype of such a device and its mathematical description taking into considerations a thermal balance, have been proposed. Basing on experimental results, a connection between temperature and operating parameters of tested MR damper has been revealed.
New possibilities of the active damping of vibrations
(Wydawnictwa AGH, 2007) Bajkowski, Jerzy; Tadzik, Piotr; Zalewski, Robert
In presented paper a new proposition of granular structure, composed on the basis of granular materials placed in hermetic space with underpressure, as a damping material for vibrated steel beam has been described. Three different types of laboratory tests have been described: fundamental strength properties of granular testing specimen, bending of granular beam and damping of the steel beam vibrations using special granular structures. Obtained results revealed that the behavior of such a structure could be easily controlled by underpressure parameter. Also damping characteristics of vibrated steel beam could be controlled by changing internal underpressure value.
Criteria of estimation of active vibration isolation system in hand-held percussive tools
(Wydawnictwa AGH, 2007) Basista, Zygmunt; Książek, Marek A
The first step for the assessment and choice of comfort parameters of an active vibration isolation system of hand-held percussive power tools is the construction of appropriate dynamical model of the operator-tool-base system. The interaction between the hand and handle is composed of the passive, dynamical reaction of the hand caused by the vibration signal and a slowly varying feed force by which the operator controls the tool operation. In the paper a complex model of human-operator was proposed. Visual and tactile feedback signals coming to human nervous system were assumed as basic components of control of percussive tool by operator. It was shown that vibration comfort and work efficiency of the percussive tool are contradictory notions. Some feedback signals responsible for the control of the tool operation are attenuated by the vibration isolation system and finally when vibration comfort increases the control of the tool and the work efficiency decrease. In the paper a criterion of assessment of work comfort with percussive tool was assumed. Simulation of the proposed model of operator-tool-base system was done applying MATLAB/Simulink. The influence of parameter values of the proposed active vibration isolation system on the assumed comfort criterion was analyzed. The obtained results were graphically presented.
Sound insulation analysis of plates with piezoceramic elements
(Wydawnictwa AGH, 2007) Kozupa, Michał; Batko, Wojciech; Pietrzko, Stanisław
This paper represents general idea research to the possibilities of increasing sound insulation of plates by active control it's vibration through piezoceramic elements placed on the plane. In the preliminary research a rectangular plate 455x560 mm made of steal was analyzed. Sound insulation measurement was executed on a specialized enclosure in reverberation chamber. A PZT piezoceramic was proposed to control vibration of the plate.
Dissipation of waves energy in cables by optimal damper force
(Wydawnictwa AGH, 2007) Łatas, Waldemar; Snamina, Jacek
In this paper the problem of optimal damping force necessary to suppress the wave traveling along the cable is considered. The energy dissipated by the damper force is assumed as the objective function of the considered problem. Optimal concentrated force and optimal distributed force of damper are determined. Equations were solved using the methods of Laplace transform and numerical integration. Results are illustrated by numerical examples.