51 resultados para Mechanical vibration
Resumo:
Segmentointi on perinteisesti ollut erityisesti kuluttajamarkkinoinnin tykalu, mutta siirtym tuotteista palveluihin on lisnnyt segmentointitarvetta mys teollisilla markkinoilla. Tmn tutkimuksen tavoite on lyt selkesti toisistaan erottuvia asiakasryhmi suomalaisen liikkeenjohdon konsultointiyritys Synocus Groupin tarjoaman case-materiaalin pohjalta. K-means-klusteroinnin avulla lydetn kolme potentiaalista markkinasegmentti perustuen siihen, mitk tarjoamaelementit 105 valikoitua suomalaisen kone- ja metallituoteteollisuuden asiakasta ovat maininneet trkeimmiksi. Ensimminen klusteri on hintatietoiset asiakkaat, jotka laskevat yksikkkohtaisia hintoja. Toinen klusteri koostuu huolto-orientoituneista asiakkaista, jotka laskevat tuntikustannuksia ja maksimoivat konekannan kytttunteja. Tlle kohderyhmlle kannattaisi ehk markkinoida teknisi palveluja ja huoltosopimuksia. Kolmas klusteri on tuottavuussuuntautuneet asiakkaat, jotka ovat kiinnostuneita suorituskyvyn kehittmisest ja laskevat tonnikohtaisia kustannuksia. He tavoittelevat alempia kokonaiskustannuksia lisntyneen suorituskyvyn, pidemmn kyttin ja alempien huoltokustannusten kautta.
Resumo:
Kunnossapidon kuluista suurimman osan aiheuttavat koneiden ennakoimattomat rikkoutumiset ja niiden tuomat tuotannonpysytykset. Kunnossapidon suunnitelmallisuutta ja vikojen ennustettavuutta pyritn parantamaan erilaisin kunnonvalvonnallisin keinoin. Havaitsemalla alkava vikaantuminen ajoissa ja seuraamalla sen kehittymist luodaan mahdollisuus korjaustoimenpiteiden ja -ajankohdan hallittuun suunnitteluun ja tt kautta kustannussstihin. Tss tyss on tutkittu kompressoriyksikiden (kaasuturbiini ja keskipakokompressori) ja niiden apulaitteiden kunnossapidon menetelmi, niiden hydynnettvyytt sek mahdollisuuksia kehitt mekaanista kunnonhallintaa. Tyss pdyttiin johtoptkseen, ett kytettvien menetelmien hydynnettvyydess on kehitettv. Kunnonvalvonnan ohjeistuksia tarkennettiin vastaamaan tmn pivn tavoitteita. Todettiin mys, ett vrhtelynvalvontaan perustuva kunnonvalvontajrjestelm soveltuu hyvin kompressoriyksikiden kunnonvalvonnan jrjestelmksi. Vrhtelynvalvontaan perustuva kunnonvalvontajrjestelm luo mahdollisuuden turvallisen kyttajan ennustamiseen. Kunnonvalvonnan kehittmisen ja kyttvarmuuden parantamisen kannalta jatkotutkimuksen tekeminen kompressoriyksikiden mekaanistenlaitteiden turvallisen kyttajan ennustamiseksi on perusteltua.
Resumo:
Appearance of the vibration is the very important problem in long tool turning and milling. Current solutions of minimizing vibrations provided by different tool suppliers are very expensive. This Masters Thesis is presenting the new type of vibration free machining tools produced by Konepaja ASTEX Gear Oy that have cheaper production costs compare to competitors products. Vibration problems in machining and their todays solutions are analyzed in this work. The new vibration damping invention is presented and described. Moreover, the production, laboratory experimental modal analysis and practical testing of the new vibration free prototypes are observed and analyzed on the pages of this Thesis. Based on the testing results the new invention is acknowledged to be successful and approved for further studies and developments.
Resumo:
Itsearviointiraportissa kuvataan Lappeenrannan teknillisen yliopiston konetekniikan kandidaatin ja diplomi-insinrin tutkinto-ohjelmat opetussuunnitelman 2011-2012 mukaisesti. Itsearviointiraportti on tuotettu saksalaisen ASIIN-akkreditointiorganisaation raportointimallin mukaisesti.
Resumo:
Multibody simulation model of the roller test rig is presented in this work. The roller test rig consists of a paper machines tube roll supported with a hard bearing type balancing machine. The simulation model includes non-idealities that are measured from the physical structure. These non-idealities are the shell thickness variation of the roll and roundness errors of the shafts of the roll. These kinds of non-idealities are harmful since they can cause subharmonic resonances of the rotor system. In this case, the natural vibration mode of the rotor is excited when the rotation speed is a fraction of the natural frequency of the system. With the simulation model, the half critical resonance is studied in detail and a sensitivity analysis is performed by simulating several analyses with slightly different input parameters. The model is verified by comparing the simulation results with those obtained by measuring the real structure. Comparison shows that good accuracy is achieved, since equivalent responses are achieved within the error limit of the input parameters.
Resumo:
Rajoitetoimet, erityisesti sitominen, nuorisopsykiatrisessa hoitotyss Tutkimuksen tavoitteena oli kuvata ja syvent tietoa rajoitetoimien, erityisesti sitomisen, kytst nuorisopsykiatrisessa vastentahtoisessa osastohoidossa. Tutkimuksen tavoitteena oli kuvata hoitajien, lkreiden ja potilaiden asenteita eri rajoittamiskeinoja kohtaan nuorisopsykiatrisessa osastohoidossa, kert tietoa yhden vuoden aikana tapahtuneiden sitomisten mrst ja luonteesta sek kuvata potilaiden kokemuksia sitomisesta nuorisopsykiatrisen osastohoidon aikana. Tutkimus tuottaa arvokasta tietoa korkeatasoisten sitomiskytntjen kehittmiseen nuorisopsykiatrisessa osastohoidossa, sek sitomisten mr vhentmll ett sitomistapoja kehittmll. Tavoitteena on parantaa sidottujen potilaiden kliinist hoitoa. Tutkimusaineisto kerttiin suomalaisilla, pkaupunkiseudulle sijoittuvilla, nuorisopsykiatrisilla osastoilla neljss vaiheessa lokakuun 2009 ja huhtikuun 2012 vlisen aikana. Helsingin ja Uudenmaan sairaanhoitopiirin (HUS) nuorisopsykiatrian erikoisalan seitsemn suljetun osaston hoitohenkilkunta sek lkrit suhtautuivat mynteisesti rajoittamistoimenpiteisiin. Nuorisopsykiatriset potilaat suhtautuivat rajoittamistoimenpiteisiin kriittisemmin kuin henkilkunta. Nuoret suhtautuivat mynteisimmin tarvittaessa annettavaan lkitykseen, ajoittaiseen tarkkailuun ja kulun rajoittamiseen. Vhiten hyvksytty menetelm oli verkkosnky. Nuoret arvioivat sitomisen kolmen vhiten hyvksytyn menetelmn joukkoon. Sitomisen esiintyvyys ja pitkien sitomisten mr olivat korkeita tutkimukseen valituissa yksikiss. Useimmat sidotut nuoret tiesivt syyn sitomiseensa, suhtautuivat siihen ambivalentisti nhden siin sek hyty ett haittaa, piten sit kuitenkin rangaistuksena. Huolimatta tst, suurin osa haastatelluista nuorista koki, ett joissain tilanteissa sitomista tarvitaan nuorisopsykiatrisessa osastohoidossa. Nuorilla oli monia ehdotuksia, kuinka parantaa sitomista kytnnn osastohoidossa. Tm vitskirja tuottaa uutta tietoa eri rajoittamistoimenpiteiden ja sitomisen toteuttamisesta nuorisopsykiatrisessa osastohoidossa. Kytnnn hoitotyn parantamiseksi nuorisopsykiatrisilla osastoilla tarvitaan laaja-alaista ja syvlle luotaavaa koulutusta, jotta rajoittamis-toimenpiteiden mr voidaan vhent. Mys kriisitilanteiden hallintaan tarvitaan uusia keinoja. Tietoa, kuvausta toimenpiteist ja tilanteiden ksittely jlkikteen tulee tarjota ala-ikiselle potilaalle hnen kehitystasonsa huomioiden. Sitomisten mr tulee vhent ja niiden kestoa lyhent. Nuorten tulee olla aktiivisesti mukana kehittmss aggression hallintamenetelmi suomalaisessa nuorisopsykiatrisessa osastohoidossa.
Resumo:
Papper kan anses vara ett av de mest anvnda materialen i det dagliga livet. Tidskrifter, tidningar, bcker och diverse frpackningar r ngra exempel p pappersbaserade produkter. Papperets egenskaper mste anpassas till anvndningsndamlet. En tidskrift krver t.ex. hg ljushet, opacitet och en slt yta hos papperet, medan dessa egenskaper r mindre viktiga fr en dagstidning. Allt tryckpapper behver vissa mekaniska egenskaper fr att tla vidarebearbetning ssom kalandrering, tryckning och vikning. Man kan bestryka papper fr att frbttra dess optiska egenskaper och tryckbarhetsegenskaper. Vid bestrykning appliceras en dispersion av mineralpigment och polymerbindemedel som ett tunt lager p papperets yta. Bestrykningsskiktet kan ses som ett komplext, porst kompositmaterial som ven bidrar till papperets mekaniska egenskaper och dess processerbarhet i diverse konverteringsoperationer. Kravet p framstllning av frmnligt papper med tillrckliga styrkeegenskaper stller allt hgre krav p optimeringen av pappersbestrykningsskiktets egenskaper och produktionskostnader. Mlet med detta arbete var att frst sambandet mellan pigmentbestrykningsskiktets mikrostruktur och dess makroskopiska, mekaniska egenskaper. Resultaten visar att adhesionen i grnsytan mellan pigment och bindemedel r kritisk fr bestrykningsskiktets frmga att bra mekanisk belastning. Polra vtskor r vanliga i tryckfrger och kan, eftersom de pverkar syra/bas-interaktionerna mellan pigment och latexbindemedel, frsvaga denna adhesion. Resultaten tyder p att ytstyrkan hos bestruket papper kan hjas genom anvndning av bifunktionella dispergeringsmedel fr mineralpigment. Detta medfr inbesparingar i pappersproduktionen eftersom mngden bindemedel, den dyraste komponenten i bestrykningsskiktet, kan minskas.
Resumo:
Large amplitude bus bar aeolian vibration may lead to post insulator damage. Different damping applications are used to decrease the risk of large amplitude aeolian vibration. In this paper the post insulator load caused by the bus bar aeolian vibration and the effect of damping methods are evaluated. The effects of three types of bus bar connectors and three types of primary structures are studied. Two actual damping devices, damping cable and their combinations are studied. The post insulator loads are studied with strain gage based custom made force sensors installed on the both ends of the post insulator and with the displacement sensor installed on the midpoint of the bus bar. The post insulator loads are calculated from the strain values and the damping properties are determined from the displacement history. The bus bar is deflected with a hanging weight. The weight is released and the bus bar is left to free damped vibration. Both actual bus bar vibration dampers RIBE and SBI were very effective against the aeolian vibration. Combining vibration damper with damping cable will increase the damping ratio but it may be unnecessary considering the extra effort. Bus bar connector type or primary structure have no effect on the vertical load. The bending moment at the post insulator with double sided bus bar connector is significantly higher than at the post insulator with single sided bus bar connector. No reliable conclusions about bus bar connector type effect can be done, but the roller bearing type or central bearing type connector may reduce the bending moment. The RHS steel frame as primary structure may increase the bending moment peak values since it is the least rigid primary structure type and it may start to vibrate as a response to the awakening force of the vibrating bus bar.
Resumo:
A high final brightness is desired in most paper and board products. This requires bleaching processes that are able to produce high-brightness pulps. Mechanical pulps are widely bleached for high brightness using alkaline hydrogen peroxide with traditional sodium hydroxide and sodium silicate as additives. With high doses however, peroxide bleaching causes high organic loads in the mill effluent and anionic trash carry-over to papermaking. To alleviate the problems that arise from the use of sodium-based additives in peroxide bleaching, interest in the use of alternative magnesium-based chemicals has increased. In this study, a new, technical high-purity magnesium hydroxide-based bleaching additive was evaluated on laboratory-scale, pilot-scale and mill-scale experiments and trials for its ability to produce a high brightness in peroxide bleaching without the known problems of sodium-based chemicals. The key findings of this study include: a high brightening potential of peroxide bleaching using the Mg(OH)2-based additive, significant reductions (40-70%) in all categories of environmental load, and cationic demand lowered by 60-70% in bleached pulp with no loss in strength properties or in sheet bulk. When used in TMP refiner bleaching, the Mg(OH)2-based additive resulted in savings in specific energy consumption and provided a good bleaching response.
Resumo:
The interferometer for low resolution portable Fourier Transform middle infrared spectrometer was developed and studied experimentally. The final aim was a concept for a commercial prototype. Because of the portability, the interferometer should be compact sized and insensitive to the external temperature variations and mechanical vibrations. To minimise the size and manufacturing costs, Michelson interferometer based on plane mirrors and porch swing bearing was selected and no dynamic alignment system was applied. The driving motor was a linear voice coil actuator to avoid mechanical contact of the moving parts. The driving capability for low mirror driving velocities required by the photoacoustic detectors was studied. In total, four versions of such an interferometer were built and experimentally studied. The thermal stability during the external temperature variations and the alignment stability over the mirror travel were measured using the modulation depth of the wide diameter laser beam. Method for estimating the mirror tilt angle from the modulation depth was developed to take account the effect from the non-uniform intensity distribution of the laser beam. The spectrometer stability was finally studied also using the infrared radiation. The latest interferometer was assembled for the middle infrared spectrometer with spectral range from 750 cm1 to 4500 cm1. The interferometer size was (197 95 79) mm3 with the beam diameter of 25 mm. The alignment stability as the change of the tilt angle over the mirror travel of 3 mm was 5 rad, which decreases the modulation depth only about 0.7 percent in infrared at 3000 cm1. During the temperature raise, the modulation depth at 3000 cm1 changed about 1 . . . 2 percentage units per Celsius over short term and even less than 0.2 percentage units per Celsius over the total temperature raise of 30 C. The unapodised spectral resolution was 4 cm1 limited by the aperture size. The best achieved signal to noise ratio was about 38 000:1 with commercially available DLaTGS detector. Although the vibration sensitivity requires still improving, the interferometer performed, as a whole, very well and could be further developed to conform all the requirements of the portable and stable spectrometer.
Resumo:
Trfibrernas naturliga egenskaper begrnsar deras anvndning i mnga tillmpningar. Trfibrernas egenskaper kan modifieras genom att binda nya komponenter med nskade egenskaper till fiberns yta. DI Stina Grnqvist bevisade i sin avhandling att nya funktionella grupper kan bindas till ligninhaltiga trfibrer genom att aktivera ytligninet med lackasenzym. Resultaten kan utnyttjas till att frbttra de traditionella trfibrernas och fiberprodukternas egenskaper samt att hitta nya tillmpningar fr trfibrerna. Om trfibrerna t.ex. modifieras s att de blir vattenavsttande kan de modifierade trfibrerna anvndas istllet fr plast i frpackningar berttar Stina Grnqvist. Syftet med denna avhandling var att underska effekterna av lackasenzym p TMP (termomekanisk massa) och dess fraktioner. I Finland tillverkas TMP av gran och massan innehller rikligt med lignin. Nr ytligninet p trfibrernas yta modifieras med hjlp av oxiderande enzymer, ssom lackas, bildas reaktiva radikaler i ligninen p fibrernas ytor. De bildade radikalerna kan utnyttjas till att binda komponenter med nya egenskaper till fiberytan. Fr att kunna utnyttja den fulla potentialen av den lackasbaserade modifieringsmetoden behvs mera information om s vl de faktorer som pverkar bildningen av radikaler som om mekanismerna hur de nya komponenterna binds till fibrerna ___________________________________ Puukuitujen luontaiset ominaisuudet rajoittavat niiden hydyntmist joissakin sovelluksissa. Ominaisuuksia voidaan kuitenkin muuttaa liittmll kuidun pintaan uusia yhdisteit. DI Stina Grnqvist osoitti vitstyssn, ett uusia kuitujen ominaisuuksia muuttavia funktionaalisia yhdisteit voidaan sitoa ligniinipitoisiin puukuituihin aktivoimalla kuitujen pinnan ligniini lakkaasi-entsyymill. Tutkimuksen tuloksia voidaan hydynt ligniinipitoisten puukuitujen ominaisuuksien parantamiseen ja jopa tysin uusien ominaisuuksien kehittmiseen. Jos kuituja muutetaan vett hylkivksi sitomalla kuituihin vett hylkivi yhdisteit entsyymien avulla, voidaan puukuituja kytt korvaamaan muovia pakkauksissa, kertoo Stina Grnqvist. Vitstyn kohteena oli TMP-massan eli kuumahiertmll valmistetun mekaanisen puumassojen ja niiden fraktioiden muokkaaminen lakkaasi-entsyymill (TMP, Thermomechanical pulp). Suomalainen TMP-massa valmistetaan kuusesta ja siin on runsaasti muokkaamatonta ligniini. Kun puukuidun pinnan ligniini muokataan hapettavilla entsyymeill, muodostuu kuidun pintaan reaktiivisia radikaaleja. Syntyneiden radikaalien avulla kuituihin voidaan liitt yhdisteit, jotka antavat kuidulle uusia ominaisuuksia. Menetelmn tarjoamien mahdollisuuksien hydyntmiseksi tarvitaan tietoa kuidun radikalisointiin ja yhdisteiden liittmiseen vaikuttavista tekijist.
Resumo:
A comparison between two competing models of an all mechanical power transmission system is studied by using Dymola software as the simulation tool. This tool is compared with Matlab/ Simulink software by using functionality, user-friendliness and price as comparison criteria. In this research we assume that the torque is balanceable and transmission ratios are calculated. Using kinematic connection sketches of the two transmission models, simulation models are built into the Dymola simulation environment. Models of transmission systems are modified according to simulation results to achieve a continuous variable transmission ratio. Simulation results are compared between the two transmission systems. The main features of Dymola and MATLAB/ Simulink are compared. Advantages and disadvantages of the two softwares are analyzed and compared.
Resumo:
Tss tyss on tutkittu modulaarisen aktiivimagneettilaakeroidun koelaitteen mekaanista suunnittelua ja analysointia. Suurnopeusroottorin suunnittelun teoria on esitelty. Lisksi monia analyyttisi mallinnusmenetelmi mekaanisten kuormitusten mallintamiseksi on esitelty. Koska kyseess on suurnopeusshkkone, roottoridynamiikka ja sen soveltuvuus suunnittelussa on esitelty. Magneettilaakerien rakenteeseen ja toimintaan on tutustuttu osana tt tyt. Kirjallisuuskatsaus nykyisist koelaitteista esimerkiksi komponenttien ominaisuuksien tunnistamiseen ja roottoridynamiikan tutkimuksiin on esitelty. Tyn rajauksena on konseptisuunnittelu muunneltavalle magneettilaakeroidulle (AMB) koelaitteelle ja suunnitteluprosessin dokumentointi. Muunneltavuuteen pdyttiin, koska se mahdollistaa erilaisten komponenttiasetteluiden testaamisen erilaisille magneettilaakerikokoonpanoille ja roottoreille. Ppaino tss tyss on suurnopeus induktiokoneen roottorin suunnittelussa ja mallintamisessa. Modulaaristen toimilaitteiden kuten magneettilaakerien ja induktioshkmoottorin rakenne on esitelty ja modulaarisen rakenteen kytettvyyden hydyist koelaitekytss on dokumentoitu. Analyyttisi ja elementtimenetelmn perustuvia tutkimusmenetelmi on kytetty tutkittaessa suunniteltua suurnopeusroottoria. Suunnittelun ja analysoinnin tulokset on esitelty ja verrattu keskenn eri mallinnusmenetelmien vlill. Lisksi johtoptkset shkmagneettisten osien liittmisen monimutkaisuudesta ja vaatimuksista roottoriin ja toimilaitteisiin sek mekaanisten ett shkmagneettisten ominaisuuksien optimoimiseksi on dokumentoitu.
Resumo:
The dissertation proposes two control strategies, which include the trajectory planning and vibration suppression, for a kinematic redundant serial-parallel robot machine, with the aim of attaining the satisfactory machining performance. For a given prescribed trajectory of the robot's end-effector in the Cartesian space, a set of trajectories in the robot's joint space are generated based on the best stiffness performance of the robot along the prescribed trajectory. To construct the required system-wide analytical stiffness model for the serial-parallel robot machine, a variant of the virtual joint method (VJM) is proposed in the dissertation. The modified method is an evolution of Gosselin's lumped model that can account for the deformations of a flexible link in more directions. The effectiveness of this VJM variant is validated by comparing the computed stiffness results of a flexible link with the those of a matrix structural analysis (MSA) method. The comparison shows that the numerical results from both methods on an individual flexible beam are almost identical, which, in some sense, provides mutual validation. The most prominent advantage of the presented VJM variant compared with the MSA method is that it can be applied in a flexible structure system with complicated kinematics formed in terms of flexible serial links and joints. Moreover, by combining the VJM variant and the virtual work principle, a systemwide analytical stiffness model can be easily obtained for mechanisms with both serial kinematics and parallel kinematics. In the dissertation, a system-wide stiffness model of a kinematic redundant serial-parallel robot machine is constructed based on integration of the VJM variant and the virtual work principle. Numerical results of its stiffness performance are reported. For a kinematic redundant robot, to generate a set of feasible joints' trajectories for a prescribed trajectory of its end-effector, its system-wide stiffness performance is taken as the constraint in the joints trajectory planning in the dissertation. For a prescribed location of the end-effector, the robot permits an infinite number of inverse solutions, which consequently yields infinite kinds of stiffness performance. Therefore, a differential evolution (DE) algorithm in which the positions of redundant joints in the kinematics are taken as input variables was employed to search for the best stiffness performance of the robot. Numerical results of the generated joint trajectories are given for a kinematic redundant serial-parallel robot machine, IWR (Intersector Welding/Cutting Robot), when a particular trajectory of its end-effector has been prescribed. The numerical results show that the joint trajectories generated based on the stiffness optimization are feasible for realization in the control system since they are acceptably smooth. The results imply that the stiffness performance of the robot machine deviates smoothly with respect to the kinematic configuration in the adjacent domain of its best stiffness performance. To suppress the vibration of the robot machine due to varying cutting force during the machining process, this dissertation proposed a feedforward control strategy, which is constructed based on the derived inverse dynamics model of target system. The effectiveness of applying such a feedforward control in the vibration suppression has been validated in a parallel manipulator in the software environment. The experimental study of such a feedforward control has also been included in the dissertation. The difficulties of modelling the actual system due to the unknown components in its dynamics is noticed. As a solution, a back propagation (BP) neural network is proposed for identification of the unknown components of the dynamics model of the target system. To train such a BP neural network, a modified Levenberg-Marquardt algorithm that can utilize an experimental input-output data set of the entire dynamic system is introduced in the dissertation. Validation of the BP neural network and the modified Levenberg- Marquardt algorithm is done, respectively, by a sinusoidal output approximation, a second order system parameters estimation, and a friction model estimation of a parallel manipulator, which represent three different application aspects of this method.
