Establishment of a novel predictive reliability assessment strategy for ship machinery

There is no doubt that recent years, maritime industry is moving forward to novel and sophisticated inspection and maintenance practices. Nowadays maintenance is encountered as an operational method, which can be employed both as a profit generating process and a cost reduction budget centre through an enhanced Operation and Maintenance (O&M) strategy. In the first place, a flexible framework to be applicable on complex system level of machinery can be introduced towards ship maintenance scheduling of systems, subsystems and components.;This holistic inspection and maintenance notion should be implemented by integrating different strategies, methodologies, technologies and tools, suitably selected by fulfilling the requirements of the selected ship systems. In this thesis, an innovative maintenance strategy for ship machinery is proposed, namely the Probabilistic Machinery Reliability Assessment (PMRA) strategy focusing towards the reliability and safety enhancement of main systems, subsystems and maintainable units and components.;In this respect, the combination of a data mining method (k-means), the manufacturer safety aspects, the dynamic state modelling (Markov Chains), the probabilistic predictive reliability assessment (Bayesian Belief Networks) and the qualitative decision making (Failure Modes and Effects Analysis) is employed encompassing the benefits of qualitative and quantitative reliability assessment. PMRA has been clearly demonstrated in two case studies applied on offshore platform oil and gas and selected ship machinery.;The results are used to identify the most unreliability systems, subsystems and components, while advising suitable practical inspection and maintenance activities. The proposed PMRA strategy is also tested in a flexible sensitivity analysis scheme.There is no doubt that recent years, maritime industry is moving forward to novel and sophisticated inspection and maintenance practices. Nowadays maintenance is encountered as an operational method, which can be employed both as a profit generating process and a cost reduction budget centre through an enhanced Operation and Maintenance (O&M) strategy. In the first place, a flexible framework to be applicable on complex system level of machinery can be introduced towards ship maintenance scheduling of systems, subsystems and components.;This holistic inspection and maintenance notion should be implemented by integrating different strategies, methodologies, technologies and tools, suitably selected by fulfilling the requirements of the selected ship systems. In this thesis, an innovative maintenance strategy for ship machinery is proposed, namely the Probabilistic Machinery Reliability Assessment (PMRA) strategy focusing towards the reliability and safety enhancement of main systems, subsystems and maintainable units and components.;In this respect, the combination of a data mining method (k-means), the manufacturer safety aspects, the dynamic state modelling (Markov Chains), the probabilistic predictive reliability assessment (Bayesian Belief Networks) and the qualitative decision making (Failure Modes and Effects Analysis) is employed encompassing the benefits of qualitative and quantitative reliability assessment. PMRA has been clearly demonstrated in two case studies applied on offshore platform oil and gas and selected ship machinery.;The results are used to identify the most unreliability systems, subsystems and components, while advising suitable practical inspection and maintenance activities. The proposed PMRA strategy is also tested in a flexible sensitivity analysis scheme

Monifysikaalisen energiavirtaus-simulaattorin kehitys ja hyödyntäminen irtolastialuksen energiatehokkuuden parantamiseen

Due to more stringent legislation regarding ship emissions and higher fuel prices, ships owners and naval architects have lately been focusing more on energy efficiency. Traditionally, ship design process has been concentrating on optimizing the ship in one design point, where the ship is the most efficient in. However, ships are not always operating near design points, and thus, the optimization to a single design point does not lead to holistic optimization of ship energy efficiency. Therefore, ship designers require a tool that takes into account varying operation conditions and ship parameters. This thesis introduces a simulation tool for handysize bulk carrier for utilization in concept design phase. The tool is based on multi-domain energy flow method. This tool covers all the main machinery components such as main engine, diesel generators, exhaust gas and oil fired-boilers and cooling circuits. The dynamic results acquired from the tool include fuel and energy consumption for main- and auxiliary engines, steam energy produced from the exhaust gas and oil-fired boilers, sea water pump mass flow and evaporator energy consumption. Simulation tool was applied to two different case studies. First, a steam system was modified by lowering steam pressure produced by the exhaust gas boiler. Secondly, cooling circuit components were optimized for obtaining lower total fuel consumption. In the first case, the energy recovered from the exhaust gas was higher and thus oil fired boiler was less utilized, as was expected. This also leads to lower fuel consumption and maintenance costs. In the second case, the results were also as expected. The variable speed drive sea water pump decreases the total fuel consumption and maintenance costs of auxiliary engines due to less electrical energy utilized. The validation of results was excluded from the thesis, and thus, the results are just guide values rather than absolute truth. Therefore, the simulation tool is suitable for quick analysis to be utilized in concept phase and is usable by any designer, without an extensive background of ship machinery.Tiukentuvat säädökset laivojen päästöjen osalta ja polttoainehintojen noususta on ohjannut varustamot ja laivasuunnittelijat keskittymään lisää energiatehokkuuteen. Perinteisesti, laivan suunnitteluprosessi on fokusoitunut optimoimaan laivan yhteen suunnittelupisteeseen, jossa laiva on hyötysuhteeltaan parhaimmillaan. Laivat eivät aina kuitenkaan operoi lähellä suunnittelupistettä, ja täten laivan optimointi suunnittelupisteen ympärille ei ole kokonaisvaltaisesti tehokkainta. Näin on tarve kehittää laivan suunnittelijoille työkalu, joka ottaa huomioon vaihtelevat operointi olosuhteet ja laivan parametrit. Tässä työssä esitellään handy-kokoluokan irtotavara-aluksen simulointityökalu, jota käytetään konseptivaiheessa. Työkalu käyttää monifysikaalista energiavirtaus menetelmää. Työkalu käsittää kaikki pääkomponentit kuten pääkoneen, diesel-generaattorit, lämmöntalteenoton- ja öljypoltinkattilat sekä jäähdytyspiirin. Työkalulla saadaan dynaamisia tuloksia kuten polttoaine- ja energiankulutuksia pää- sekä apumoottoreille, höyryenergian tuotto lämmöntalteenotto- ja öljypoltinkattilasta, merivesipumpun massavirta sekä makeanvedenkehittimen energian kulutus. Simulointityökalua sovellettiin kahdessa eri tapaustutkimuksessa. Ensimmäisessä tapauksessa höyrysysteemi modifioitiin alentamalla lämmöntalteenottokattilan tuottamaa höyrynpainetta. Toisessa tapauksessa jäähdytyspiirin komponentit optimoitiin pienemmälle polttoaineenkulutukselle. Ensimmäisen tapauksen tulos oli odotettavissa eli lämmöntalteenottokattilan tuottama höyryenergia kasvoi ja vastaavasti öljypoltinkattilaa käytettiin vähemmän. Tämä johti pienempään polttoaineen kulutukseen ja pienempiin huoltokustannuksiin. Myös toisessa tapauksessa tulos oli odotettavissa. Taajuusmuuttajaan kytketty merivesipumppu alentaa kokonaispolttoainekustannuksia ja apumoottoreiden huoltokustannuksia pienemmän sähkönkulutuksen takia. Tulosten varmentaminen rajattiin työn ulkopuolelle, joten ne ovat vain suuntaa-antavia. Tästä syystä simulointityökalu on sopiva nopeaan analyysiin, jota käytettäisiin konseptivaiheessa ja olisi kenen tahansa suunnittelijan käytettävissä, riippumatta kyseisen suunnittelijan taustasta laivan koneistoissa

Index to 1981 NASA Tech Briefs, volume 6, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1981 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Aaltoenergiavoimalaitoksen sähkötehontuottoyksikön testilaitteen suunnittelu

Wave energy means producing electricity from ocean waves. After decades of reseach, and a multitude of prototype devices installed, this renewable energy source is still globally untapped, despite its high energy production potential. One of the design challenges in wave energy converters is the marine environment. Installing and testing devices in their actual domain is difficult and expensive. To mitigate this, the devices must be tested on dry land before deployment. Simulations and small scale experiments are vital in this process, but can only go so far. Especially, the product development of a hydraulic power take-off unit without a full scale test device is almost impossible. This work presents the test bench of a wave energy converter called WaveRoller, and proposes a new control algorithm for the test bench. The test bench is used in the power take-off unit product development and the commercialization of the wave energy converter. In its task, it has been a vital help. 350 kW marine version of the wave energy converter and its power take-off module developed using the test bench is under construction, and will be commissioned in Peniche, Portugal during 2017. The findings of this thesis will be used to further refine the test bench, and the improved test bench will be used to develop new models of power take-off units.Aaltoenergialla tarkoitetaan sähkön tuottamista meren aaltoliikkeestä. Vuosikymmenten tutkimuksen ja monien testilaitteiden jälkeen tämä uusiutuvan energian muoto on maailmanlaajuisesti vielä hyödyntämättä, huolimatta korkeasta potentiaalisesta energiantuotantokapasiteetista. Eräs merkittävä aaltoenergian suunnitteluhaaste on meriympäristö. Laitteiden asennus ja testaus oikeassa toimintaympäristössään on vaikeaa ja kallista. Tämän vuoksi laitteita tulee testata mahdollisimman pitkälle kuivalla maalla. Simulaatioilla ja pienen mittakaavan testeillä voidaan päästä pitkälle, mutta etenkin hydraulisen sähkötehontuotantoyksikön tuotekehitys on lähes mahdotonta ilman täyden mittakaavan koelaitetta. Tämä työ esittelee WaveRoller-nimisen aaltoenergiavoimalaitoksen sähköntuotantoyksikön täysikokoisen koelaitteen testipenkin, ja kehittää sitä varten uuden säätöalgoritmin. Testipenkin tarkoitus on auttaa aaltoenergiavoimalaitoksen tuotekehityksessä. Testipenkin tulee mallintaa mahdollisimman tarkasti voimia, joita aallot aiheuttavat laitteeseen, ja tässä tehtävästä se suoriutuu hyvin. 350 kW:n mereen asennettava versio sähkötehontuottoyksiköstä on rakenteilla, ja se tullaan asentamaan 2017 Portugalin Penicheen. Tämän työn löydöksiä tullaan hyödyntämään uusien laitemallien suunnittelussa