Spelling suggestions: "subject:"alibration - 1ieasurement"" "subject:"alibration - remeasurement""
61 |
Tillståndsövervakning av hydraulpumpar med smarta vibrationssensorer / Condition monitoring of hydraulic pumps with smart vibration sensorsGabra, Ahmed January 2022 (has links)
Detta arbete har genomförts på uppdrag av SCA Munksund, för att undersöka möjligheten att tillståndsövervaka hydraulpumpar med hjälp av smarta sensorer som mäter vibrationer och temperatur. Hydraulpumpar är svåra att tillståndsövervaka, och möjligheten att prediktera ett haveri i ett tidigt skede är väldigt svårt. Haverier på hydraulpumpar sker oftast inte direkt efter att ett fel har uppstått, utan efter en längre period, med däremot sker haverier på hydraulpumpar oftast utan förvarning och är mycket kostsamma för processindustrin, där materialkostnaden utgör en liten del jämfört med kostnaden som följd av produktionsförlusten. En möjlighet för bättre och effektivare tillståndsövervakning är att använda vibrationssensorer som i ett tidigt skede indikerar när pumpen avviker från sitt normaltillstånd, och på så sätt planera in underhållsarbete vid exempelvis nästkommande underhållsstopp, utan att behöva stoppa produktionen. Just därför har det valts att undersöka olika sensorparametrar för att identifiera hydraulpumparnas normaltillstånd, och utifrån det bestämma lämpliga larmgränser. Vibrationsmätningarna har genomförts under ca en månad på två hydraulpumpar, en som är relativt ny och en som är äldre. Huvudfokuset har varit att övervaka vibration och temperatur under varierande pumpbelastning/effekt och även att övervaka kolvslitage och lagertillstånd. Med användning av smarta vibrationssensorer har larmgränser kunnat identifierats för båda pumparna. Däremot måste fler mätningar utföras för att säkerställaatt de larmgränser som presenteras i denna rapport är korrekta och kan användas i framtiden. SCA Munksund har nu tillgång till alla mätningar och dokumentation som har utförts för båda hydraulpumparna, och kan nu arbeta vidare för att på sikt tillhandhålla mer specifika larmgränser. / This work has been carried out on behalf of SCA Munksund, to investigate the possibility of condition monitoring hydraulic pumps using smart sensors that measure vibrations and temperature. Hydraulic pumps are difficult to condition monitor, and the ability to predict a failure at an early stage is very difficult. Breakdowns on hydraulic pumps usually do not happen immediately after a fault has occurred, but after a longer period, but on the other hand, breakdowns on hydraulic pumps usually happen without warning and are very costly for the process industry, where the cost of materials constitutes a small part compared to the cost resulting from the loss of production. One possibility for better and more efficient condition monitoring is to use vibration sensors that indicate at an early stage when the pump deviates from its normal state, and in this way plan maintenance work at, for example, the next maintenance stop, without having to stop the production. Precisely for this reason, it has been chosen to investigate various sensor parameters to identify the normal state of the hydraulic pumps and based on that to determine suitable thresholds. Vibration measurements have been carried out for about a month on two hydraulic pumps, one that is relatively new and one that is older. The main focus has been on monitoring vibration and temperature under varying pump load/effect and also to monitor piston wear and bearing condition. With the use of smart vibration sensors, thresholds have been identified for both pumps. However, more measurements must be performed to ensure that the thresholds presented in this report are correct and can be used in the future. SCA Munksund now has access to all measurements and documentation that have been carried out for both hydraulic pumps and can now work further to provide more specific thresholds.
|
62 |
Trafikinducerade vibrationer : En studie om busskuddars påverkan på vibrationsnivåer i mark och byggnader. / Traffic induced vibrations : A study on the effect of speed control cushions on vibration levels in surrounding land and buildings.Johansson Kling, Erika January 2019 (has links)
Trafikinducerade vibrationer: En studie om busskuddars påverkan på vibrationsnivåer i mark och byggnader. Erika Johansson Kling I Uppsala används busskuddar som en form av medveten ojämnhet i vägbanan för att sänka hastigheten och öka trafiksäkerheten på olycksdrabbade vägsträckor. Boende i bostäder belägna nära busskuddar har dock rapporterat att de ibland kan uppleva vibrationer kopplade till då tunga fordon passerar busskuddar som störande. Denna studie syftade till att kvantifiera vibrationsnivåer i mark och byggnader nära busskuddar samt utreda centrala faktorer som kan påverka vibrationsnivån och vibrationsutbredningen. Genom vibrationsmätningar i fält på fyra platser i Uppsala samlades data in och analyserades utifrån angivna frågeställningar. Resultatet bekräftade det som litteraturstudien belyste, att det är svårt att på ett generellt sätt beskriva vibrationsutbredningen och att den tydligt är platsspecifik. Vid samtliga undersöka platser kunde dock konstateras att vibrationsnivån i marken tenderar att vara en faktor mellan 2,5–32 högre då ett tungt fordon passerar en busskudde, jämfört med då det passerar en opåverkad referenspunkt längs med samma väg. Generellt avtog dessutom vibrationsnivån i marken med ökat avstånd från källan. Vilken vibrationsled som dominerade varierade dock både mellan platserna och för olika avstånd från källan. Vid en av de fyra mätplatserna förstärktes vibrationsnivån i byggnaden, jämfört med i marken utanför. Vid samma mätplats överskreds dessutom känseltröskeln inomhus, och en skyddsvibrationsnivå på 0,5 mm/s kan behöva tillämpas vid busskudden för att förhindra detta. Mätningarna visade att både vibrationer med låga och höga frekvenser kan uppstå i marken nära busskudden då tunga fordon passerar. Dock var det enbart vibrationer med låga frekvenser som spreds vidare i marken vid ett ökat avstånd från källan. Studien visade dessutom att det kan krävas ett skyddsavstånd mellan busskudde och byggnad på cirka 100 meter för att känseltröskeln inte ska riskera att överskridas inomhus. Trots att ett sådant avstånd är platsspecifikt, belyser det vilka krav det skulle kunna ställa på samhällsbyggnaden i ett växande Uppsala. Det faktum att busskuddar kan förhöja vibrationsnivån i marken vid passage av tunga fordon ter sig något märkligt, då busskuddarna ska vara utformade på ett sätt som tillåter tunga fordon att passera relativt obehindrat. Fler studier kring busskuddarnas utformning och/eller grundläggning är därför av stor relevans. Det är vidare relevant att exempelvis utreda hur fordonens hastighet över busskuddar påverkar vibrationsnivån i marken, då litteraturstudien belyser att det främst är då tunga fordon passerar ojämnheter med hög hastighet som betydande vibrationer kan uppstå. Busskuddar anses vara en av de mest effektiva hastighetssänkande åtgärderna, men studien visar att det kan ske på bekostnad av ökade vibrationsnivåer. En grundläggande helhetsbedömning bör därför göras av busskuddarnas lämplighet vid kommande stadsplanering. Nyckelord: markvibration, vibrationsmätning, busskudde, trafik, samhällsbyggnad. Institutionen för geovetenskaper, Uppsala Universitet, Villavägen 16, SE-752 36 Uppsala. ISSN 1401–5765. / Traffic induced vibrations: A study on the effect of speed control cushions on vibration levels in surrounding land and buildings. Erika Johansson Kling In Uppsala, speed control cushions are used as a form of conscious unevenness in the road surface to reduce speed and increase road safety on accident-affected road sections. However, housing in residences located near speed control cushions have reported that they can sometimes experience vibrations linked to when heavy vehicles pass speed control cushions as disturbing. This study aimed to quantify vibration levels in land and buildings near speed control cushions and to investigate key factors that can affect the vibration level and vibration propagation. Through vibration measurements at four places in Uppsala, data was collected and analyzed based on the stated research questions. The result confirmed what the literature study highlighted, that it is difficult to describe the propagation of vibrations in a general way and that it is clearly site-specific. However, it was found at all the measurement sites that the vibration level in the ground tends to be a factor between 2.5 and 32 higher when a heavy vehicle passes a speed control cushion, compared to when it passes an unaffected reference point along the same road. Generally, the vibration level in the ground also decreased with increased distance from the source. However, the level of vibration that dominated varied between the locations and for different distances from the source. At one measurement site, the vibration level in the building was amplified compared to in the ground outside. At the same measurement site, the sensing threshold was also exceeded indoors, and a protection vibration level of 0.5 mm/s may have to be applied nearby the speed control cushions to prevent this from happening. The measurements showed that both vibrations with low and high frequencies can occur in the ground near the speed control cushions when heavy vehicles pass. However, it was only vibrations with low frequencies that propagated further in the ground at an increased distance from the source. The study also showed that a safety distance between speed control cushions and buildings of approximately 100 meters may be required in order for the sensitivity threshold not to be exceeded indoors. Although such a distance is sitespecific, it highlights what requirements it could put on the urban planning in a growing Uppsala. The fact that speed control cushions can increase the level of vibration in the ground when heavy vehicles pass seems somewhat strange, since the speed control cushions are supposed to be designed in a way that allows heavy vehicles to pass relatively unobstructed. Additional studies on the design and/or foundation of the speed control cushions are therefore of great relevance. It is furthermore relevant to investigate, for example, how the speed of the vehicles when passing over speed control cushions affects the vibration level in the ground, since the literature study highlights that it is primarily when heavy vehicles pass an unevenness in the road surface at high speed that significant vibrations can occur. Speed control cushions are considered to be one of the most effective speed reducing measures, but the study shows that they may lead to increased vibration levels. An overall 3 evaluation should therefore be made regarding the suitability of speed control cushions in future urban planning. Keywords: ground vibration, vibration measurement, speed control cushion, traffic, urban planning. Department of Earth Sciences, Uppsala University, Villavägen 16, SE-752 36 Uppsala. ISSN 1401–5765.
|
63 |
Avaliação da vibração e ruído ocupacionais no fresamento de pisos industriaisGonçalves, Felyppe Blum 23 March 2015 (has links)
A constante mudança nos meios de trabalho ocorre devido a evolução tecnológica e industrial. Entretanto, com o advento de tais inovações, dificilmente o trabalhador da indústria não é submetido aos mais variados riscos ocupacionais resultantes dos processos produtivos. Diante deste contexto, o presente estudo teve como objetivo principal avaliar os níveis de vibração e de ruído aos quais os trabalhadores de uma empresa do setor da construção civil, especializada na manutenção e reformas de pisos industriais, estavam expostos durante suas jornadas de trabalho em duas frentes de trabalho. As medições foram realizadas em locais e dias distintos nos municípios de Curitiba e de São José dos Pinhais, ambos no estado do Paraná. Para a avaliação da vibração ocupacional, utilizou-se um acelerômetro junto ao trabalhador e um sensor triaxial acoplado na empunhadura dos equipamentos objeto de estudo, que foram duas diferentes fresadoras de piso. Posteriormente os dados foram processados e comparados com o novo texto do Anexo no 08 da Norma Regulamentadora NR-15, apresentado para consulta pública pelo Ministério do Trabalho e Emprego entre os meses de janeiro e fevereiro de 2014. Já para a medição do ruído utilizou-se um dosímetro de ruído junto ao trabalhador, cujo resultado final possibilitou a comparação com o Anexo no 01 da mesma Norma Regulamentadora. Os resultados finais indicaram níveis de exposição excessivos, superiores aos limites de tolerância determinados pela Legislação, tanto para vibração quanto para o ruído, gerando insalubridade para os trabalhadores expostos, em todos os locais onde foram realizadas as medições. / The constant change in the means of work is done by technological and industrial developments. However, with the advent of such innovations, hardly the work of the industry is not subject to a variety of occupational hazards resulting from production processes. Given this context, the present study aimed to monitor the working hours of the employees of a company in the construction industry, specializing in industrial floor maintenance and renovations, as exposure of vibration and noise on two fronts work in the cities of Curitiba - PR and São José dos Pinhais – PR. The program took place in two locations and on different days. The workday adopted by the company is six hours daily. For the evaluation of vibration, we used accelerometer with the worker and coupled to the handle of the equipment object of study, a mill floor, triaxial sensor subsequently the data were processed and compared with the new text of Annex No. 08, NR 15, submitted for public consultation by the Ministry of Labour and Employment in the months of January and February 2014. As for noise measurement used a dosimeter with the worker, whose final results enabled comparison with the regulatory norm 15 - Annex No. 01. The final results indicate excessive exposure to the tolerance specified by the legislation, both vibration and sound pressure level, featuring unhealthy at all locations where measurements were performed.
|
64 |
Analýza dynamických parametrů laserových vibrometrů / Analysis of dynamic parameters of laser vibrometersPavloň, Martin January 2017 (has links)
This diploma thesis deals with the theoretical description of interference methods used to measure vibrations, examines main parasitic effects and analyses its contribution to achievable the resolution. In the practical part, it uses several measurements to verify the effects of the level of reflected beam, stand-off distance and speckle noise. It also proposes a practical experiment for measuring dynamic parameters and signal-noise ratio. Results show that, the noise is exponentially dependent on the level of the reflected beam. The visible maximum of the vibrometer proved to be critical in terms of time stability of the measured signal level in two of the three measurements. Results of the dynamic measurement show that, the measured deviations were not degraded or significantly disturbed by the noise signal. From the measurement of the speckle noise, it emerged that the lowest level of noise is achieved with smooth and highly reflective materials.
|
65 |
Prediction of engine component loads using previous measurementsMikaelsson Elmén, Pär January 2017 (has links)
Internal combustion engines are used in many applications. The same engine type may have different components mounted to it depending upon its use. These engine mounted components need to be designed against fatigue in order to withstand the engine vibrations. Measured engine vibrations are commonly used as input data for fatigue estimation. The focus in this thesis is set on heavy-duty diesel engines, typically used in trucks, buses and industrial applications. All of the appended papers use engine vibration measurements to evaluate the proposed methods. In Paper A, the engine block motion is described with a seven degree of freedom kinematic model. These degrees of freedom consist of six rigid body modes and one assumed twisting degree of freedom. With this description, measured engine block vibrations can be used to accurately predict the vibration in positions that have not been measured. Relating the measured vibrations of an engine mounted component with the projected motion of the engine block at that same position, makes it possible to identify local dynamic phenomena. In Paper B, the kinematic model of Paper A is extended with three assumed bending deformation mode shapes. For the current engine type, all of the assumed deformation modes are ranked within the 10-300 Hz frequency range. The deformation mode of highest importance is the engine block twist. Including bending deformation increases the accuracy of the engine block vibration description but it also increases the demands on instrumentation. In Paper C, the possibility to modify measured engine vibration signals, for addition or removal of engine mounted components, is investigated. For this purpose, engine vibration measurements were performed with and without a 29 kg brake air compressor mounted to the engine. For the task of removing the effect that this engine mounted component has on the engine block, the two cases of knowing, and not knowing the vibration of the component are both considered. The proposed methodology successfully predicts the changes in engine vibration due to system modification. The proposed method can also be used to estimate the time response of a component's centre of gravity. In this study the component's dynamic properties are derived from measurements but they could also be produced using finite element analysis. This can be useful early in the design process to find critically stressed areas due to base excitation. / <p>QC 20171222</p>
|
66 |
Usure ondulatoire en transport ferroviaire: mécanismes et réduction / Rail corrugation in railway transport: mechanism and mitigationCollette, Christophe 05 July 2007 (has links)
L'usure ondulatoire des rails associée aux vibrations de torsion des essieux de métro a été mise en évidence il y a près d'un demi siècle. L'utilisation d'absorbeurs dynamiques comme solution potentielle à ce problème a été suggérée pour la première fois dans le projet américain du TCRP "Rail Corrugation Mitigation in Transit" en 1998. Cette thèse, réalisée dans le cadre du projet européén "Wheel-rail CORRUGATION in Urban transport", a pour objectif de concevoir un absorbeur dynamique et d'étudier son influence sur la réduction de l'usure ondulatoire liée aux vibrations de torsion. Dans le cadre de ce travail, d'autres types d'usure ondulatoire ont également été traités par des absorbeurs dynamiques.<p><p>Les trois premiers chapitres de cette thèse sont dédiés à la description des différents types d'usure ondulatoire et à la présentation des méthodes de prédiction. La méthode de dimensionnement des absorbeurs dynamiques est présentée au chapitre 4, ainsi que quelques perspectives de leur efficacité à réduire l'usure ondulatoire. Dans le chapitre 5, un tronçon réel du RER parisien a été étudié. D'une part les prédictions obtenues par différentes méthodes ont été comparées aux mesures sur site. D'autre part, le bénéfice résultant de l'utilisation d'un absorbeur dynamique a été étudié numériquement. Dans le chapitre 6, le cas de l'usure ondulatoire liée aux vibrations de torsion a été étudié spécifiquement. Un absorbeur dynamique a été développé pour réduire ce type d'usure ondulatoire. Son efficacité a été évaluée théoriquement et numériquement, avec un modèle multi-corps flexible du véhicule et de la voie. Dans le chapitre 7, un absorbeur dynamique visant à réduire les vibrations de torsion d'un essieu de métro à échelle réduite a été construit au laboratoire. Son efficacité a été validée expérimentalement en reproduisant les conditions d'apparition des vibrations de torsion de l'essieu sur le banc d'essais du Laboratoire des Technologies Nouvelles de l'INRETS. La correspondance entre les prédictions d'usure à échelle réduite et à échelle réelle a été établie. Une demande de brevet a été déposée par le Laboratoire des Structures Actives pour ce système (N° 06120344.4). / Doctorat en sciences appliquées / info:eu-repo/semantics/nonPublished
|
Page generated in 0.1531 seconds