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Author:Järvi, Heikki
Title:Hydraulijärjestelmän komponenttien vaikutus sylinteridynamiikkaan matalilla taajuuksilla
The effect of hydraulic components on cylinder dynamics at low frequencies
Publication type:Master's thesis
Publication year:2014
Pages:(5) + 42      Language:   fin
Department/School:Koneenrakennustekniikan laitos
Main subject:Koneensuunnittelu   (K3001)
Supervisor:Pietola, Matti
Instructor:Kajaste, Jyrki
Electronic version URL: http://urn.fi/URN:NBN:fi:aalto-201412033097
OEVS:
Electronic archive copy is available via Aalto Thesis Database.
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Location:P1 Ark Aalto  4794   | Archive
Keywords:hydraulic cylinder
dynamic stiffness
resonator
vibration damping
hydraulisylinteri
dynaaminen jäykkyys
resonaattori
värähtelynvaimennus
Abstract (eng):Pressure vibration occurs in hydraulic systems introduced by either system components or external forces.
Different types of resonators, in addition to the system components themselves, can be used to alter the frequency response of the system.

Different methods were researched to affect on the dynamic stiffness of a hydraulic cylinder by passive resonators and alternative hydraulic fluids.
Also the effect of pipeline was studied.
The research focuses on hydraulic systems containing a hydraulic cylinder.
Frequency band is limited to sub 50 Hz due to prior researches focusing on higher frequencies.
Research material consists of a simulation model and a test apparatus.

The results of this research indicate that the dynamic stiffening of a hydraulic system by pipeline resonator is possible at a narrow frequency band.
Increasing the mechanical stiffness of the pipeline can also introduce a substantial rise in the dynamic stiffness of the hydraulic system.
Significant lowering of the stiffness is practically precluded by seal friction.
Abstract (fin):Hydraulijärjestelmissä esiintyy joko järjestelmän komponenttien tai ulkopuolisten kuormitusten aiheuttamaa painevärähtelyä.
Järjestelmän värähtelyvasteeseen voidaan vaikuttaa järjestelmän keskeisimpien komponenttien lisäksi erilaisilla putkistoresonaattoreilla.

Työssä tutkittiin erilaisia mahdollisuuksia muokata hydraulisylinterin dynaamista jäykkyyttä hydraulijärjestelmään kytkettävillä passiivisilla resonaattoreilla ja vaihtoehtoisilla hydraulinesteillä.
Myös putkiston ominaisuuksien vaikutusta selvitettiin.
Tutkimus rajattiin käsittelemään järjestelmää, jossa toimilaitteena on hydraulisylinteri.
Taajuusalue rajattiin alle 50 Hz taajuuksiin, koska aiemmat tutkimukset ovat keskittyneet korkeampiin taajuuksiin.
Tutkimusaineisto koostuu simulointimalleista ja koelaitteesta.

Tutkimustulosten perusteella hydraulijärjestelmän dynaaminen jäykistäminen putkistoresonaattorin avulla on mahdollista kapealla taajuusalueella.
Myös putkiston mekaanisella jäykkyydellä voidaan selvästi kasvattaa järjestelmän dynaamista jäykkyyttä.
Jäykkyyden merkittävä alentaminen sen sijaan ei käytännössä saada aikaan tiivistekitkan takia.
ED:2014-12-21
INSSI record number: 50182
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