Mechanics and Control
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ISSN 2083-6759
e-ISSN: 2300-7079
Issue Date
2010
Volume
Vol. 29
Number
No. 3
Description
Journal Volume
Mechanics and Control
Vol. 29 (2010)
Projects
Pages
Articles
Phase trajectory analysis in investigation of swash plate degradation processes in axial piston pump
(2010) Batko, Wojciech; Stojek, Jerzy
Test of assessing a suitability of the phase trajectory pattern for diagnostics of condition changes of axial piston pumps is undertaken in the presented paper. Accomplishment reasons of investigations together with their laboratory realizations are given. They concerned the experimental comparison of changes in the phase trajectory patterns of the hydraulic pump working with a constant output pressure, in which an element of swash plate was degraded. The performed tests confirmed the suitability of phase trajectories in the recognition of degradation changes in axial piston pumps. The paper signals the usefulness of considering the introduction of phase trajectory patterns of the monitored vibration signals into processes of the diagnostic inspection of the hydraulic pump structural elements.
Numerical method for determining allowable medium temperature during operation of steam gate valve
(2010) Duda, Piotr; Rząsa, Dawid
Construction elements of power blocks such as collectors, separators or steam valves work in hazardous environment. During start-up and shut-down operations they are exposed to sudden temperature and pressure changes, that cause high stresses at certain points. Additionally, the cyclic character of loading causes material fatigue, known as low-cyclic fatigue, which may lead to the formation of fracture. Manufacturers of steam boilers provide instructions for heating and cooling processes in order to operate safely. It is important to find the optimum parameters for heating and cooling operations, i.e. parameters that enable to conduct heating and cooling in the shortest time and keep the maximum stresses in the construction within allowable limits. Efforts are made to develop an appropriate method for determining optimum operating parameters during start-up and shut-down phase of the power units. In this paper two optimum parameters will be found. Based on these parameters heating and cooling processes will be carried out and compared with heating and cooling operations processed according to the German boiler regulations Technische Regeln fur Dampfkessel 301 (TRD).
Effect of selected working conditions of cutting picks on their wear during the mining of hard rocks
(2010) Kotwica, Krzysztof
The article presents the influence of work conditions of rotary-tangential picks on their wear while compact rocks mining. There was mainly presented the influence of applying high-pressure support and spraying the tangent-rotary tools with water jets on their quantitative and qualitative wear during conducted laboratory tests in comparison to tools operating in dry conditions. There was suggested and presented a solution of holders lubricated with water under pressure to provide proper conditions of tangent-rotary tools work in the clamp. The results of laboratory tests of rotary-tangential picks fixed in the folders were presented and compared with results of picks only supported or sprayed with high-pressure water jets.
The designing process and stand tests of a new solution of a mining head with disc tools of complex motion trajectory for compact rocks mining
(2010) Kotwica, Krzysztof; Stopka, Grzegorz; Kalukiewicz, Antoni; Gospodarczyk, Piotr
The article presents a new solution of a mining head with asymmetrical disc tools of a complex motion trajectory for hard rocks mining. The developed and manufactured head is to be an alternative for traditional milling heads used in roadheaders. The basis for the head development was elaborated based on laboratory tests performed in the AGH University of Science and Technology in Krakow. The technical design and the head were implemented in cooperation with the factory of REMAG S.A. in Katowice. The head, mounted on the KR 150 roadheader, underwent field tests. Their results allowed modernisation of the head and its adaptation to further industrial tests in mining plants.
Comparison of passive and active methods for sound radiation reduction from the clamped plate
(2010) Kozupa, Michał; Wiciak, Jerzy
The paper is an analytical and experimental study of smart structure, which consist of steel plate with bonded PZTs and porous elastomer layer. Active control of sound radiation from a clamped at the edge square plate is examined. Simulations and numerical computation of the experiment are performed in ANSYS environment. Calculations of plate vibration and sound radiation under stepped harmonic force are performed. The experimental set-up is placed in coupled reverberation chambers and the test plate is placed in the hole. A variety o test cases were studied for three different plates: steel plate + PZT, steel plate + elastomer layer, steel plate + PZT + elastomer layer. The aim of the paper is to illustrate the possibilities of using piezoelectric materials as an active control and elastomer layers as passive methods in one structure to improve the transmission loss.