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  • 1.
    Abrahamsson, Marcus
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Magnusson, Christian
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Svensson, Henrik
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Evrat, Xavier
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Driving Module For Existing Flight Carts2002Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    We needed to design an electric-driven module to place underneath a serving-cart, to facilitate the work made by the cabin personal and thereby prevent work injuries.

  • 2.
    Almgren, Gustaf
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Fogelqvist, Christopher
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Tjädermark, Anders
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Nytt koncept för linspridning2001Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    Summary The degree project, New concept for spreading line, consists of further development of a baitcasting reel. The baitcasting reel that was used as a starting-point was Ambassadeur Classic 5000c, which is a former product. Abu Garcia is the company that initiated the project. The purpose consisted of designing a baitcasting reel, which could provide free casts. At today's baitcasting reel is the line forced to pass through the mechanism that spreads the line. This causes the line to follow the motion from the spreader-mechanism, during the cast. Because of this fact there will be a great deal of friction, which results in a shorter cast. If the spreader-mechanism would not be in contact with the fishing-line during the cast, it would provide a longer cast. It is important that the spreader-mechanism spreads the line at once when the user starts winding it up. If not, the line will create disorder on the spool, which may prevent the next cast. Integrated Product Development created by Professor Fredy Olsson, consists of a concept, a primary and a prototype design phase and has been used through the project. Twelve different principal suggestions due to the problem were produced in the concept design phase. These suggestions were further developed and evaluated. Two suggestions were brought into the primary design phase, which resulted in one finally product solution. There were two different solutions in the beginning of the primary design phase. One solution was based on an endless screw, which makes it possible to spread the line on the spool. Abu Garcia has investigated this matter according to the complex geometry of the endless screw. There for has no further development of this proposal been performed. During the primary concept phase parts were developed, components selected and also detail constructions of new parts were performed. The finally concept were produced with facilities like I-DEAS, which is a 3D-tool. The prototype design phase consist of manufacturing the parts and to make them fit together with the other parts and components. A test of the final product should also have been done, however a lack of time has prevented this.

  • 3.
    Andersson, Carry
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Kisswani, Lennart
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Dynamic Characteristics of a Tool Holder Shank in Lathe2000Other (Other academic)
    Abstract [en]

    Dynamic characteristics of a Tool Holder Shank were determined by using the Finite Element Method and Experimental Modal Analysis. Good agreement between FE-model and the experimental model was obtained for the Tool Holder Shank itself. With the Tool Holder Shank in Lathe the agreement was less good. Reasons for this are discussed. Suggestions for further work on including actuators to reduce vibrations are given.

  • 4. Bathelt, Jens
    et al.
    Jönsson, Anders
    How to Implement the Virtual Machine Concept Using xPC Target2003Conference paper (Refereed)
    Abstract [en]

    This paper presents an overview of the historical background of the virtual machine, containing a real control, a machine simulation and a 3D machine visualisation. This setup enables realistic system simulations, since the simulation input comes from a real control. The first known implementation of the virtual machine using xPC Target is described with an existing water jet cutting machine as an example. MathWorks products offer all necessary software for the presented setup, except the interface for the actual speed value from the simulated incremental encoder to the control. The unique xPC driver implementation, as a noninlined C-MEX S-Function, is presented at the end of this paper. The successful implementation of the virtual machine demonstrates the feasibility of the presented approach.

  • 5. Bathelt, Jens
    et al.
    Jönsson, Anders
    Bacs, Christian
    Kunz, Andreas
    Meier, Markus
    Conceptual Design Approach For Mechatronic Systems Controlled by a Programmable Logic Controller (PLC)2003Conference paper (Refereed)
    Abstract [en]

    Traditionally, the development of mechatronic systems starts with the mechanical design. Later electronic components and program logic for the product are added. This work proposes an improved interdisciplinary concurrent product development process with an enhanced function structure for the conceptual design phase. The new methodology is based on the German guideline VDI 2221 [1]. Transition conditions, time aspects and logic flow are added to the normal function structure. An example shows how to use the improved function structure. The enhanced function structure is used to derive the initial logic for the development of the PLC program controlling the machine later on. Since the extended function structure also covers the traditional information, it can still be used when building the assembly tree. By adding more information in the neutral function structure, the same information can be used for the mechanical design as well as for the electronic and logical design. The interdisciplinary communication and documentation among the engineers will be improved and errors in the concept will be detected earlier.

  • 6. Bathelt, Jens
    et al.
    Jönsson, Anders
    Bacs, Christian
    Meier, Markus
    Modularisierung SPS-gesteuerter mechatronischer Systeme2003Conference paper (Refereed)
    Abstract [en]

    Rein mechanische Lösungen werden zunehmend von mechatronischen Systemen abgelöst. Der X-by-wire Ansatz zeigt auch, dass der Anteil an mechanischen Teillösungen eines mechatronischen Systems immer weiter zurückgeht. Der vorliegende Beitrag skizziert einen Entwicklungsprozess für SPS-gesteuerte mechatronische Systeme, der dem immer wichtiger werdenden Steuerungsanteil Rechnung trägt. Dabei steht das parallele Arbeiten der Steuerungstechnik und der Konstruktion im Vordergrund, um die Entwicklungszeiten zu verkürzen und Fehler früher zu erkennen. Realisiert wird dies durch eine fachspezifische Modularisierung, deren erste Modulhierarchie als Ausgangslage der jeweiligen Disziplinen fungiert und somit einen parallelen Start ermöglicht. In dieser Arbeit werden Regeln vorgestellt, um die fachspezifischen Module von einer Funktionsstruktur abzuleiten. Abschliessend wird das Vorgehen anhand eines Industriebeispieles erläutert.

  • 7.
    Bengtsson, Oskar
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Bien, Bartosz
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Gonzalez, Carlos Cortes
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Hansson, Marcus
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Ringström, David
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Simonson, Victor
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    VB-400 calculation and development project2001Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    Abstract The purpose with this thesis has been to develop a new platform and to make calculations of the lifting device to wheelchair lift VB-400. The project has been performed in association with U-LIFT AB in Backaryd. The task formulation were: 1. Develop a suggestion to construction of a new platform made in aluminium for the wheelchair lift VB-400. The platform should be able to be used on the existing lifting-device. 2. Make stress calculations of the lifting device for the wheelchair lift VB-400. The project with developing the new platform in aluminium has been performed in alignment with Fredy Olsson?s method for integrated product development. The parts of the method that been used are principal-construction and primary-construction. The new platform turned out to have a weight loss of about 30% even though it has a much bigger area compared to the old platform. The aluminium-section which been used to build the floor gave the platform a new and innovative design. Despite the big reduction of weight the new platform can stand for at least the same amount of stress and torsion that the old one did. It also fulfils the norms of the factor of safety.

  • 8.
    Berglund, Pierre
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Pettersson, Johan
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Dynamic Characteristics of Exhaust System Hangers1999Other (Other academic)
    Abstract [en]

    Comfort in automobiles is greatly affected by vibrations and noise transmitted to the chassis from the engine. This is a study of the dynamic characteristics of exhaust system hangers, which is an important transfer path for vibrations. Theoretical and experimental modal analysis is used to suggest design parameters that increase the natural frequencies to above 450 Hz for two hanger types.

  • 9.
    Björkman, Simon
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Törnblom, Micael
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Metod och anordning för åstadkommande av stegrande presskraft i balpress2003Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [sv]

    Det finns flera olika sätt att konkurrera med en balpress på marknaden. Ett av dessa är att minska cykeltiden för en komplett pressoperation. Härav formulerades en problemställning som lade grunden för examensarbetet. Problemställningen löd ”Metod och anordning för åstadkommande av stegrande presskraft i balpress, Nättraby Verktyg AB.” Sambandet mellan minskad cykeltid och stegrande presskraft gav lösningen med varierande hastighet på pressplattan. För att lösa problemet valdes en frekvensomriktare som omriktar matningsfrekvensen till elmotorn. Då ingen presskraft erfordras utnyttjas motorns fulla effekt till att förflytta pressplattan med en högre hastighet. När högre presskraft erfordras så minskar matningsfrekvensen och motorn antar en lägre vinkelhastighet men ett högre vridmoment. Resultatet är en balpress med en varierande hastighet och stegrande presskraft som pressar samman en bal med en tidsvinst på 20 minuter jämfört med den nuvarande balpressen NP80, som Nättraby Verktygs AB tillverkar idag. Tillvägagångssättet har varit att först utarbeta en detaljerad kravspecifikation som var till stor hjälp vid det fortsatta utvecklingen av produktförslag. Sedan har delar av metoden för Integrerad produktutveckling av Fredy Olsson används för att sortera de kriterier som uppställdes i kravspecifikationen. Vid framtagning och utvärdering av produktförslagen viktades kriterierna mot förslagen för att sedan få fram det förslag som bäst motsvarar de krav och önskemål som angivits. Förslaget benämns ”frekvensomvandlaren”.

  • 10.
    Bohlin, Jens
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Karlsson, Morgan
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Tuvesson, Richard
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Simulering av bordläggningslucka2002Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [sv]

    Kockums i Karlskrona har givit i uppdrag att ta fram lösningar till öppningsmekanismen för större bordläggningsluckor på marina ytfartyg. De önskar att luckans dimension ska vara max 10 * 3 m. I uppgiften ingår att ta fram en lösning på öppningsmekanism, simulera öppning och stängningsförloppet i Virtual Reality samt utvärdera konstruktionen enligt givna lastfall. Acceleration är ett exempel på laster som luckan kan tänkas utsättas för under öppet läge samt under öppning och stängning. Första delen av rapporten innehåller principkonstruktionen, här har det tagits fram ett antal lösningsförslag som visas med enkla skisser. Dessa utvärderas i olika omgångar mot de krav och önskemål som tagits fram i samarbete med Kockums. Förslagen som förs vidare till primärkonstruktionen har utvärderats i samarbete mellan Kockums och studenterna som deltagit i projektet. I primärkonstruktionen valdes sedan det förslaget som i rapporten kallas Förskjutaren. Alla komponenter som ingår i produkten har valts och dimensionerats för att passa in i den miljö och de lastfall som råder. De resultat som beräknats fram analytiskt har sedan verifierats med hjälp av beräkningsprogram i högskolans datorer. Konstruktionen är uppbyggd av tre armar som roterar ut en lucka på 10*3 meter. Luckan hålls parallell mot skrovet genom att den mittersta armen är förskjuten i sin infästning och därmed fungerar som parallellstag. Den roterande rörelsen utförs genom att tre hydraulcylindrar trycker på armarna. Samtidigt som armarna roterar hissas luckan uppåt med hjälp av två andra hydraulcylindrar som monteras på luckan. En viktig del har varit att simulera konstruktionen i Virtual reality och i ADAMS. De sekvenser som gjorts i VR har sedan använts för att kunna åskådliggöra hela öppningsförloppet på ett tydligt sätt.

  • 11.
    Brandt, Kristina
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Gylling, Siv
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Rening av avloppsvatten efter skärprocess2001Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    ABB I-R Waterjet Systems kombinerar robot- och rörelseteknik från ABB Flexible Automation med högtryckspumpteknologi från Ingersoll-Rand. Därigenom har man utvecklat innovativa vattenskärningssystem för en global marknad. Uppgiftens syfte är att till ABB I-R’s produktionsceller, som säljs under produktnamnet Cutting-Box, ta fram en reningsanläggning för använt processvatten vid vattenskärning. Vattnet skall i första hand renas till den grad att det får släppas ut i det kommunala avloppet, men den ultimata lösningen på problemet är att få fram ett slutet system där vattnet kan recirkuleras. Vid sökning av lämpliga reningssätt blev första steget att inrikta sökandet på befintliga principer och därtill hörande tillverkare av reningsanläggningar och deras produkter. Dessa olika produkter jämfördes sedan och den mest tillämpbara produkten valdes ut. Filtrering visade sig vara den metod som är enklast att tillämpa, kan användas stegvis, är billig och finns både som återanvändnings- och engångsfilter. Eftersom skärvattnet innehåller en förhållandevis stor mängd partiklar i olika storlekar är det nödvändigt att utföra filtreringen stegvis. Processvattenreningsanläggningen är därför uppbyggd av en grovfiltreringsmodul och en mikrofiltreringsmodul. I grovfiltreringsmodulen filtreras alla större partiklar bort. Dessa fångas upp i containervagn som sedan kan tömmas ut på lämpligt ställe. I mikrofiltreringsmodulen sker filtreringen i två steg. Första steget filtrerar bort synliga partiklar (partiklar större än 50m), andra steget säkrar en viss storlek på partiklarna i vattnet som sedan släpps vidare, antigen till recirkulering eller avlopp.

  • 12. Broman, Göran
    Computational Engineering2003Book (Other academic)
    Abstract [en]

    This book is the main course literature in the course Computational Engineering, which comprises 22,5 ECTS (European Credit Transfer System), within the programme of Master of Science in Mechanical Engineering with emphasis on Structural Mechanics at Blekinge Institute of Technology. The book starts with rather simple numerical methods for ordinary differential equations and ends with advanced topics such as finite element procedures for systems of transient, non-linear and coupled partial differential equations. Several topics from physics and engineering are included to support the study of the numerical methods.

  • 13. Broman, Göran
    Implications of cavitation in individual grooves of spiral groove bearings2001In: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 215, no J5, p. 417-424Article in journal (Refereed)
    Abstract [en]

    The pressure distribution in a flat spiral groove thrust bearing obtained from a straightforward solution of the Reynolds equation includes subatmospheric pressure in part of the grooved area, This is masked in the common theory based on the assumption of an infinite number of grooves. Furthermore, the negative contribution to the load capacity from this area is usually small, which may explain why the presence of subatmospheric pressure has not been given much attention in connection with these bearings. Subatmospheric pressure is, however, necessary for liquid-lubricated flat spiral groove thrust bearings of conventional design to work at all at low numbers of grooves, which in turn requires a non-zero cavitation pressure. Cavitation within individual grooves implies non-linearity in, for example, the relation between load capacity and rotational speed of the bearing and limits the obtainable load capacity. This is more pronounced and important to consider at low numbers of grooves (wide grooves) than at high numbers of grooves (narrow grooves), and it is difficult to determine for what number of grooves that reliable prediction of bearing performance can be expected. It depends on the actual value of the cavitation pressure and other parameters that are usually unknown or difficult to account for. To avoid this disadvantage a modified design of liquid-lubricated flat spiral groove thrust bearings is suggested.

  • 14.
    Broman, Göran
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Miljöinslag i grundutbildningen vid Högskolan i Karlskrona/Ronneby1997Other (Other academic)
    Abstract [sv]

    Högskolan i Karlskrona/Ronneby grundades 1989, och är därmed en av Sveriges yngsta högskolor. Grundutbildning bedrivs inom ämnesområdena teknik, datavetenskap, arbetsvetenskap, ekonomi, språk och kultur. Antalet anställda är ca 220 och antalet studenter ca 2500. Utvecklingstakten är hög och fortfarande kännetecknas ledning och personal av pionjäranda och öppenhet för initiativ, vilket varit till glädje också för detta projekt. Tillämpad informationsteknologi ges hög prioritet och finns som ett naturligt inslag i hela högskolans verksamhet. En målsättning är att också integrera miljöaspekter. Genom anslag från Högskolans Grundutbildningsråd till detta projekt påbörjades 1994 miljöintegrering inom 120p-programmet i maskinteknik med inriktning mot utvecklingsteknik, vid Institutionen för Maskinteknik (IMA), och 180p-programmet i fysisk planering, vid Institutionen för Fysisk Planering och Byggteknik (IFB). Biblioteket deltog också från början för att ge stöd åt projektledning och lärare vid deras integreringsarb ete, samt för att miljöintegrera sin egen verksamhet som stöd för personal och studenter även fortsättningsvis. Ett delmål med projektet var att ge deltagande lärare och övrig personal sådana kunskaper om bärkraftig utveckling - och nödvändigheten därav - att de skulle känna engagemang och själva se möjligheterna till miljöinslag i sina respektive ämnen och övriga yrkesuppgifter. Stor vikt lades därför på personalutbildning, som genomfördes i form av en seminarieserie samt genom handledda fortsatta självstudier och deltagande i externa kurser, konferenser och studiebesök. Resultatet blev gott. Nästan alla lärare vid IMA och IFB fick ett ökat engagemang och deltog aktivt i miljöintegreringsarbetet. Engagemanget har också borgat för fortsatt lärande och automatiska kursförbättringar efter projektets slut, vilket var tanken. Synliga resultat är en vidareutvecklad miljögrundkurs, Miljögrunder 5p, obligatorisk i programmet maskinteknik med inriktning mot utvecklingsteknik och tillgänglig även för andra studenter s om fristående kurs, samt nya kursplaner i de ämnen miljöintegrering bedömts mest relevant i de båda programmen. Även i examination, projektrapporter och examensarbeten syns naturligtvis resultat av miljöintegreringen. Totalt har ca hälften av kurserna inom respektive utbildningsprogram direkt berörts av projektet. Genom följdeffekter har i någon mån även övriga delar av programmen påverkats. Studenterna framför vid kurs-utvärderingar och andra diskussioner att de upplever miljöintegreringen som mycket positiv för deras utbildning och ser den som en värdefull merit då de söker jobb. Miljöinslag har kunnat införas utan att de reguljära ämnena tagit skada - alltså i motsägelse till diskussionen om att värdefulla befintliga kunskaper måste trängas undan när någon "nymodighet" ska föras in i en utbildning. Miljöintegreringen har snarare gjort att studenternas motivation för de reguljära ämnena ökat. Denna tulipanaros har kunnat åstadkommas huvudsakligen genom att: - använda grundläggande kunskaper som reguljärt ingår i utbildningsprogrammen, t ex viss naturvetenskap, för att bygga upp en systemsyn genom vilken miljö- och resursproblemens orsaker och lösningar på principiell nivå blir tydliga. - använda denna systemsyn som ett ramverk i vilket detaljkunskaper som reguljärt ingår i utbildningsprogrammen kan inordnas och ges en övergripande mening, varigenom också sambanden mellan olika ämnen blir tydligare. - exemplifiera de reguljära ämneskunskaperna på ett delvis nytt sätt och visa på alternativa tillämpningar för att stimulera studenternas kreativitet beträffande hur deras yrkeskunskaper konkret kan användas för att lösa miljö- och resursproblemen. Den bärande idén med miljöintegreringen har just varit att med ovanstående som förutsättning, så är det främst genom att bli duktiga i klassiska ämnen för ingenjörer och fysiska planerare som ingenjörer och fysiska planerare kan göra den största insatsen för en bärkraftig utveckling. Att göra om dem till "miljöexperter" i traditionell mening vore inte fruktbart. Det Naturliga Stegets definition av bärkraftighet och modell för planering av bärkraftig utveckling, som visat sig så framgångsrik inom näringslivet, har visat sig lämplig även inom den högre utbildningen. Den har utgjort grunden för den systemsyn som använts i detta projekt enligt ovan. Projektet har troligen även bidragit som inspirationskälla, åtminstone som en av flera faktorer, till verksamheter utanför dess ram. Exakt hur mycket är naturligtvis svårt att bedöma. Ökade kunskaper och det allmänt ökade intresset för miljöfrågor har i varje fall lett till allt ifrån konkreta saker som införskaffande av institutionscykel för kortare ärenden och vindkraftverk och solpaneler som komplement till energiundervisningen, till deltagande i internationella miljöutbildningsprojekt, doktorandverksamhet i miljöanpassad produktutveckling, inrättandet av professurer med miljöprofil, och ansvar för högskolans miljöpolicy och miljöplan. Detta utgör naturligtvis omvänt också ett starkt stöd för underhåll och utveckling av miljöintegreringen. Den bedöms därför ha utmärkta förutsättningar att bli bestående vid IMA och IFB och förhoppningsvis sprida sig till övriga institutioner och utbildningsprogram.

  • 15.
    Broman, Göran
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Byggeth, Sophie
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Robèrt, Karl-Henrik
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Integrating Environmental Aspects in Engineering Education2002In: International journal of engineering education, ISSN 0949-149X, Vol. 18, no 6, p. 717-724Article in journal (Refereed)
    Abstract [en]

    The key role of engineers for the transformation of society towards sustainability is a strong motivation for increasing the environmental knowledge within engineering education. Doing this by the concept of integration is presently considered more appropriate than to develop more new education programmes for environmental specialists. This paper describes the integration of environmental aspects into a mechanical engineering education programme. The Natural Step Framework has been used as a basis for this integration. It has been possible to include environmental knowledge without compromising the engineering quality of the programme.

  • 16. Broman, Göran
    et al.
    Hermann, Madeleine
    Jönsson, Anders
    Modelling Bellows Expansion Joints by Standard Beam Finite Elements2000Conference paper (Refereed)
    Abstract [en]

    A procedure for modelling bellows expansion joints by the standard beam finite elements of I-DEAS Master Series 6 is presented. It is shown that the bellows dynamic behaviour can be modelled by beam elements by manipulating certain element parameters. The method will work in any software in which these parameters can be set by the user. Compared to a shell elements model the model size is reduced by at least a factor of 100. This is especially advantageous when the bellows is only a part of a system to be optimised with respect to overall design parameters. In comparison to existing "semi-analytical" methods the beam finite elements have the advantages of considering axial, bending and torsion degrees of freedom simultaneously and that the interaction between the bellows and the rest of the system, also modelled by beam or shell finite elements, is easily facilitated. The procedure is verified by experimental results from other investigators.

  • 17.
    Broman, Göran
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Hermann, Madeleine
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Jönsson, Anders
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Modelling Flexible Bellows by Standard Beam Finite Elements1999Report (Other academic)
    Abstract [en]

    A procedure for modelling flexible metal bellows by the standard beam finite elements in I-DEAS Master Series 6 is presented. In spite of the geometry of the bellows being far from a beam, it is shown that the bellows dynamic behaviour can be modelled by beam elements with the suggested procedure. The model size is reduced by a factor of 100-1000 compared to a shell elements model. This is especially advantageous when the bellows is only a part of for example an exhaust system to be optimised with respect to overall design parameters. In comparison to existing "semi-analytical" methods the standard beam finite elements have the advantages that axial, bending and torsion degrees of freedom are included simultaneously and that the interaction between the bellows and the rest of the system, also modelled by beam or shell finite elements, is easily facilitated. The procedure is verified by experimental results from other investigators.

  • 18. Broman, Göran
    et al.
    Holmberg, John
    Robèrt, Karl-Henrik
    Simplicity Without Reduction: Thinking Upstream Towards the Sustainable Society2000In: Interfaces, ISSN 0092-2102, E-ISSN 1526-551X, Vol. 30, no 3, p. 13-25Article in journal (Refereed)
    Abstract [en]

    The natural-step framework is used by over 100 organizations, including many global corporations in Europe and the United States, to provide strategic direction for their sustainability initiatives. The framework is built on the concept of simplicity without reduction. Out of respect for complexity we designed it to provide a compass, a guide for strategic direction. The framework consists of a backcasting planning process for sustainable development based on four principles (system conditions) for sustainability. The framework does not prescribe detailed actions. Once an organization understands the framework it identifies and specifies the detailed means by which to achieve the strategy, because it knows its business best. The steps in the planning process are understanding and discussing the system conditions for sustainability, describing and discussing how the company relates to the system conditions in today's situation, creating a vision of how the company will fulfill its customers' needs in the futur e while complying with the system conditions, and specifying a program of actions that will take the company from today's situation to the future vision.

  • 19. Broman, Göran
    et al.
    Jönsson, Anders
    The Nonlinear Behavior of a Rammer Soil Compactor Machine2000Conference paper (Refereed)
    Abstract [en]

    A theoretical model of a rammer compactor machine is described and its dynamic behaviour is analysed. The differential equations of the model are solved numerically by using standard software. Simulation results are presented as time series, phase plane diagrams, mappings and bifurcation diagrams. The results show that the system is highly nonlinear and indicates that harmonic, subharmonic and chaotic behaviour is present for the parameter variations used. This parameter sensitivity emphasizes the need for this kind of simulations in the product development process.

  • 20. Broman, Göran
    et al.
    Jönsson, Anders
    Hermann, Madeleine
    Determining Dynamic Characteristics of Bellows by Manipulated Beam Finite Elements of Commercial Software2000In: International Journal of Pressure Vessels and Piping, ISSN 0308-0161, E-ISSN 1879-3541, Vol. 77, no 8, p. 445-453Article in journal (Refereed)
    Abstract [en]

    A procedure for determining dynamic characteristics of bellows by manipulating certain parameters of the beam finite elements of I-DEAS Master Series 6 is presented. The method will work in any software in which these parameters can be set by the user. Compared to a shell elements model the model size is reduced by at least a factor of 100. This is especially advantageous when the bellows is only a part of a system to be optimised with respect to overall design parameters. Stress in the bellows cannot be predicted by this method, but when the dynamic behaviour is known it can be used as input for stress calculations, if desired. In contrast to existing "semi-analytical" methods this method has the potential of considering axial, bending and torsion degrees of freedom simultaneously, and it facilitates the interaction between the bellows and the rest of the system, also modelled by beam or shell finite elements. The procedure is verified by experimental results from other investigators.

  • 21. Broman, Göran
    et al.
    Jönsson, Anders
    Wall, Johan
    Englund, Thomas
    Introductory Optimisation Study of a Rammer Soil Compactor Machine2001Conference paper (Refereed)
    Abstract [en]

    Rammer compactor machines perform dynamic soil compaction. The complexity of this machine type makes design optimisation through traditional prototype testing impractical. This has pointed to the need for a theoretical model and simulation procedure for prediction of the dynamic behaviour of the machine and a procedure for optimisation as design parameters are changed during product development. In this paper a theoretical model of the rammer machine in combination with a soil model is described. This multi-body dynamics system is solved numerically. The system is non-linear and chaotic behaviour is possible. This parameter sensitivity emphasises the need for this kind of simulations in the product development process. A fairly regular behaviour is necessary for a predictable and safe operation. Parameter combinations giving too irregular behaviour are non-feasible. The energy transfer rate from the rammer machine into the soil is used as the objective function for optimisation. Multi-start Sequential Quadratic Programming for optimum search is used. To cover the design space well a Uniform Experimental Design is used for selection of starting points. This procedure proves to work well for the problem of this introductory study. The study shows a significant potential for improved compaction capacity although considering only the three design parameters that are most easily changed in practice. Approximately the same optimum is obtained both for operation on soft soil and hard soil, so a good all-round design seems possible. Including this theoretical support in the product development process should make it much more effective in finding optimum designs, also for other machines of similar type.

  • 22. Broman, Göran
    et al.
    Östholm, Stefan
    Mathcad in Teaching Rotor and Structural Dynamics1997In: International journal of engineering education, ISSN 0949-149X, Vol. 13, no 6, p. 426-432Article in journal (Refereed)
    Abstract [en]

    This paper describes how Mathcad is used to deepen understanding of fundamental aspects in the field of rotor and structural dynamics in two of the undergraduate courses in the education programme of Bachelor of Science in Mechanical Engineering with emphasis on Product Development at the University of Karlskrona/Ronneby, Karlskrona, Sweden. Integrating this mathematical software has clearly given an improved interest for mathematics as well as mechanics among the students.

  • 23. Byggeth, Sophie
    Integration of Sustainability Aspects in Product Development2001Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Integration of sustainability aspects into the product development process has been difficult to achieve, especially for small and medium-sized enterprises. The main reason is that existing tools are experienced to be too detailed and as a result too demanding in terms of time and resources. This Licentiate Thesis presents a method for sustainable product development (MSPD). The method is intended to be a complement to existing overarching sustainability management tools and detailed quantitative product analysis tools. The objectives of the MSPD are: (i) identification of potential problems of present or planned products caused by substances and activities during the product life cycle that are critical with regard to principles for sustainability; (ii) guidance in finding solutions to the potential problems by modifications of present or planned products, and (iii) promotion of new products and business ideas based on sustainability aspects. A method suitable for most enterprises, irrespective of product type or background knowledge, has been sought. The MSPD includes: (1) a management tool which supports the user with information about, and instructions for applying, the method; (2) a flexible model for an integrated product development process, including checklist questions concerning traditional aspects of product development; (3) a modular system of guiding questions concerning aspects of sustainability, and (4) a prioritisation matrix for evaluation and choice of proposals in each product development phase. A MSPD prototype has been developed and tested in six small and medium- sized enterprises to study the usability of the basic structure of the method, and to obtain ideas for improvements and further development.

  • 24. Byggeth, Sophie
    et al.
    Broman, Göran
    Environmental Aspects in Product Development: an Investigation among Small and Medium Sized Enterprises2000Conference paper (Refereed)
    Abstract [en]

    Small- and Medium sized Enterprises (SMEs) represent a large part of industry. Environmental considerations during product development in SMEs therefore imply a large potential for reducing society's environmental impact. Implementing environmentally adapted product development among SMEs has been considered difficult and is uncommon. Our approach is to develop a qualitative Method for Sustainable Product Development (MSPD) that relates both to a framework for sustainability and to the ordinary product development process. The aim is to guide the user to avoid problems related to social and ecological non-sustainability without demanding extensive expertise knowledge. Two surveys in ten Swedish SMEs have been carried out. An initial survey registered their product development procedures and environmental work as well as desired characteristics of a new suggested method for integrating environmental aspects into the product development process. A second survey registered additional desired characteristics and improvement suggestions when testing an early version of our MSPD. The surveys and the structure of our MSPD are presented, and the desired characteristics for a workable method in SMEs, found in our investigation and in literature, are discussed.

  • 25.
    Byggeth, Sophie
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Broman, Göran
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Holmberg, John
    Lundqvist, Ulrika
    Robèrt, Karl-Henrik
    A Method for Sustainable Product Development In Small and Medium Sized Enterprises2000Conference paper (Refereed)
    Abstract [en]

    A qualitative Method for Sustainable Product Development (MSPD) is presented. It consists of three tools: an Integrated Product Development Model (IPDM), a strategic planning process based on backcasting (ABCD-analysis), and a matrix containing hierarchically ordered and guiding questions. This Sustainability Product Analysis (SPA) matrix has conditions for sustainability along one axis and the life cycle of the product along the other axis. The SPA-matrix is used in the ABCD-analysis, which in turn is used in the IPDM. Integrating the tools in this way and using overall conditions for sustainability is unique compared to many other tools and methods for design for the environment. The MSPD is being developed in discussions with ten small- and medium sized enterprises.

  • 26.
    Byggeth, Sophie
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Broman, Göran
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Lundqvist, Ulrika
    Robèrt, Karl-Henrik
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Holmberg, John
    An Approach to Sustainability Product Analysis in Product Development2001Conference paper (Refereed)
  • 27. Chen, S.H.
    et al.
    Wang, Tzuchiang
    Kao-Walter, Sharon
    A crack perpendicular to a bimaterial interface an interface in finite solid2003In: International Journal of Solids and Structures, ISSN 0020-7683 , Vol. 40, no 11, p. 2731-55Article in journal (Refereed)
    Abstract [en]

    The dislocation simulation method is used in this paper to derive the basic equations for a crack perpendicular to the bimaterial interface in a finite solid. The complete solutions to the problem, including the T stress and the stress intensity factors are obtained. The stress field characteristics are investigated in detail. It is found that when the crack is within a weaker material, the stress intensity factor is smaller than that in a homogeneous material and it decreases when the distance between the crack tip and interface decreases. When the crack is within a stiffer material, the stress intensity factor is larger than that in a homogeneous material and it increases when the distance between the crack tip and interface decreases. In both cases, the stress intensity factor will increase when the ratio of the size of a sample to the crack length decreases. A comparison of stress intensity factors between a finite problem and an infinite problem has been given also. The stress distribution ahead of the crack tip, which is near the interface, is shown in details and the T stress effect is considered.

  • 28. Enflo, Bengt
    et al.
    Hedberg, Claes
    Fourier decomposition of a plane nonlinear sound wave and transition from Fubini´s to Fay´s solution of Burger´s equation1999Conference paper (Refereed)
    Abstract [en]

    Burgers' equation describes plane sound wave propagation through a thermoviscous fluid. If the boundary condition at the sound source is given as a pure sine wave, the exact solution is given by the Cole-Hopf transformation as a quotient between two Fourier series. Two approximate Fourier series representations of this solution are known: Fubini's (1935) solution, neglecting dissipation and valid at short distance from the sound source, and Fay's (1931) solution, valid far from the source. In the present investigation a linear system of equations is found, from which the coefficients in a series expansion of each Fourier coefficient can be derived one by one. Curves which join smoothly to Fubini's solution (valid up to slightly before shock formation) and to Fay's solution (valid for approximately three shock formation distances). Maxima for the Fourier coefficients of the higher harmonics are given. These maxima are situated in a region where neither Fubini's nor Fay's solution is valid.

  • 29. Enflo, Bengt
    et al.
    Hedberg, Claes
    Fourier decomposition of a plane nonlinear sound wave developing from a sinusoidal source2001In: Acustica, ISSN 0001-7884, Vol. 87, no 2, p. 163-169Article in journal (Refereed)
    Abstract [en]

    Burgers' equation describes plane sound wave propagation through a thermoviscous fluid. If the boundary condition at the sound source is given as a pure sine wave, the exact solution given by the Cole-Hopftransformation is a quotient between two Fourier series. Two approximate Fourier series representations of this solution are known: Fubini's (1935) solution, neglecting dissipation and valid at short distance from the sound source, and Fay's solution, valid far from the source. In the present investigation a linear system of equations is found, from which the coefficients in a series expansion of each Fourier coefficient can be derived one by one. Curves which join smoothly to Fubini's solution (valid up to slightly before shock formation) and to Fay's solution (valid for approximately three shock formation distances). Maxima for the Fourier coefficients of the higher harmonics are given. These maxima are situated in a region where neither Fubini's nor Fay's solution is valid.

  • 30. Enflo, Bengt
    et al.
    Hedberg, Claes
    Theory of Nonlinear Acoustics in Fluids2002Book (Other academic)
    Abstract [en]

    This book presents theoretical nonlinear acoustics in fluids with equal stress on physical foundations and mathematical methods. From first principles in fluid mechanics and thermodynamics a universal mathematical model (Kuznetsov's equation) of nonlinear acoustics is developed. This model is applied to problems such as nonlinear generation of higher harmonics and combination frequencies, the shockwave from a supersonic projectile, propagation of shocks in acoustic beams and nonlinear standing waves in resonators. Special for the book is the coherent account of nonlinear acoustic theory from a unified point of view and the detailed presentations of the mathematical techniques for solving the nonlinear acoustic model equations. The book differs from mathematical books on nonlinear wave equations by its stress on their origin in physical principles and their use for physical applications. It differs from books on applications of nonlinear acoustics by its ambition to explain all steps in mathematical derivations of physical results. It is useful for practicians and researchers in acoustics feeling the need for more theoretical understanding. It can be used as a textbook for graduate or advanced undergraduate students with an adequate background in physics and mathematical analysis, specializing in acoustics, mechanics or applied mathematics. See also http://www.wkap.nl/prod/b/1-4020-0572-5.

  • 31. Enflo, Bengt
    et al.
    Rudenko, Oleg
    Hedberg, Claes
    Nonlinear Standing Waves in a Layer Excited by the Periodic Motion of its Boundary2002Conference paper (Refereed)
    Abstract [en]

    Simplified nonlinear evolution equations describing nonsteady-state forced vibrations in an acoustic resonator having one closed end and the other end periodically oscillating are derived. An approach is used based on a nonlinear functional equation. This approach is shown to be equivalent to the version of the successive approximation method developed in 1964 by Chester. It is explained how the acoustic field in the cavity is described as a sum of counterpropagating waves with no cross-interaction. The nonlinear Q-factor and the nonlinear frequency response of the resonator are calculated for steady-state oscillations of both inviscid and dissipative media. The general expression for the mean intensity of the acoustic wave in terms of the characteristic value of a Mathieu function is derived. The process of development of a standing wave is described analytically for three different types of periodic motion of the wall: harmonic excitation, sawtooth-shaped motion and "inverse saw motion".

  • 32.
    Enwall, Anders
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Sjögren, Robert
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Simulation of Vehicle Response to Throttle Tip-in and Tip-out1999Other (Other academic)
    Abstract [en]

    A theoretical model for optimization of the dynamical behavior of a vehicle drive train was suggested and equations of motions derived. A Simulink model was developed to solve the resulting system of equations. Experimental verification showed good agreement with theory.

  • 33.
    Flakowicz, Maciej
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Gombas, Morgan
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Ajdari, Shahram
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Mekaniserad Bandslipsmaskin2002Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [sv]

    Att utveckla en utrustning för mekaniserad slipning.

  • 34.
    Fransson, Pär
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Pettersson, Gert
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Fatigue Life Prediction using Forces in Welded Plates of Moderate Thickness2000Other (Other academic)
    Abstract [en]

    A new finite element based method for fatigue life prediction has been examined. The method uses nodal forces and moments along the weld toe to define a structural stress perpendicular to the weld. The method was found to be less mesh-sensitive than ordinarie post-processing.

  • 35.
    Fristedt, Henrik
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Olsson, Marcus
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Wåhlberg, Carl-Johan
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Utveckling av formningsmodul för provning av verktygsstål2003Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [sv]

    Vid Industriellt UtvecklingsCentrum i Olofström AB utförs bland annat slitageprov av verktygsstål vid plastisk formning av plåt. Parametrar som undersöks är verktygstålsmaterial, plåtkvalitéer, ytbehandlingsmetoder, smörjning och olika kombinationer av dessa faktorer. Den nuvarande testmetoden upplevs av IUC som icke tillräckligt produktionslik. Därför skulle det vara önskvärt med ett mer produktionslikt slitagetest än det nuvarande. Vårt uppdrag var förutom att utforma ett nytt slitagetest även att undersöka intressenters synpunkter på den nuvarande testmetoden och önskemål om ett framtida slitagetest. Inledningsvis inventerades befintliga slitagetestmetoder för att försäkra sig om att särskilja det nya testet från befintliga testmetoder och kartlägga vilka egenskaper som undersöks. Eftersom önskemål om ett mer produktionslikt slitagetestmetod fanns behovet av att göra en studie för att definiera begreppet mer produktionslik. Med ledning av denna studie bestämdes att dragpressning av en rektangulär burk var en lämplig geometri. Eftersom slitagetest kommer att utföras på flertalet olika verktygsstål krävs en moduluppbyggnad av formningsenheten med lätt utbytbara slitdelar. För konstruktion av verktyget användes tillämpliga delar av Fredy Olssons metod för produktutveckling. Konstruktionsarbetet vid såväl princip- som primärkonstruktionsfasen präglades av funktion och verkningssätt vid plåtformning. Detta medförde begränsade alternativa möjligheter för innovativa lösningar av ingående delar i formningsmodulen. En stor del av konstruktionsarbetet var att välja och placera givare i verktyget för att erhålla tillförlitlig mätdata. Den slutgiltiga konstruktionen av formningsmodulen resulterade i en uppdelning i enheter bestående av en slitdel och en fästdel. Stor vikt lades vid slitdelens tillverkningsvänlighet och lättutbytbarhet. En prototyp som visar funktion och bekräftar utbytbarheten har tillverkats. Konstruktionen har anpassats för kraft-, temperatur- och akustisk-emmissionsgivare.

  • 36. Grbic, Nedelko
    et al.
    Tao, Xiao-Jiao
    Nordholm, Sven
    Claesson, Ingvar
    Blind signal separation using overcomplete subband representation2001In: IEEE transactions on speech and audio processing, ISSN 1063-6676, E-ISSN 1558-2353, Vol. 9, no 5, p. 524-533Article in journal (Refereed)
    Abstract [en]

    This paper discusses a multirate filterbank-based extended infomax algorithm for real-world signal separation, i.e., convolved mixtures separation. Since convolution in the time domain corresponds to instantaneous mixing in the frequency domain, polyphase subband projection naturally becomes an efficient alternative to the Fourier transform based frequency domain approach. The online implementation proposed is featured by a simultaneous inverse channel identification in the frequency domain and signal filtering in the time domain. It is shown that an over-representation structure reduces aliasing between different bands and results in more accurate inverse channel estimates. Therefore, it provides better performance than the Fourier transform based structure in the measures of both separation and distortion. The performance limitation of the method is also evaluated in terms of the Wiener solution.

  • 37.
    Gullberg, Pär-Ola
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Holmström, Fredrik
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Karlsson, Jonas
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Horisontalrörelse för svetsbrännare2001Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [sv]

    Att utveckla en utrustning för positionering av en svetsbrännares horisontalrörelse.

  • 38.
    Gunnarson, Helena
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Johansson, Maria
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Sterner, Lisa
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Fäste för ramar2001Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [sv]

    Syftet med detta examensarbete har varit att ta fram ett snabbfäste för ramar åt Roxtec International AB på Verkö i Karlskrona. Examensarbetet har följt metoden för Integrerad produktutveckling av Fredy Olsson. Av denna metod har två områden berörts: Principkonstruktion samt Primärkonstruktion. Primärkonstruktionen är uppdelad i två delar där den ena behandlar komponentval och detaljkonstruktion, och den andra innefattar framtagning av prototyp och en ekonomisk kalkyl. Problemställningen var följande: Att ta fram ett snabbfäste för små ramar. Ramarna används till kabelgenomföring till elskåp och liknande applikationer, och de kommer att innehålla Multidiametermoduler med inneslutna kablar och kompressionsenhet. Idag fästs ramarna med hjälp av skruvar och muttrar men det nya fästet får inte utgöras av skruvar, sprintar, fjädrar och de får ej heller svetsas fast. Fästet ska vara av enkel konstruktion, lätt att montera och demontera utan hjälp av verktyg. Produkten måste även uppfylla täthetskravet IP 54, se bilaga 1. Med hänsyn till de begränsande kraven så togs 18 principlösningar fram och de bearbetades och utvärderades med hjälp av uppställda krav och önskemål, tills slutligen bara ett förslag återstod. En prototyp tillverkades av det vinnande förslaget. Den slutliga produkten löser uppgiften åt Roxtec och har fått namnet Barnsäker.

  • 39. Haller, Kristian
    et al.
    Hedberg, Claes
    Advantages of Nonlinear Wave Modulation Spectroscopy (NWMS) compared to some linear acoustic techniques2003Conference paper (Refereed)
    Abstract [en]

    This paper describes test results of a nonlinear wave modulation spectroscopy (NWMS) technique. These techniques are based on the strong connection between nonlinearity and presence of micro or macro-cracks. NWMS includes existence of higher harmonics, the presence of sidebands and ratio between excitation frequency and sideband components. Tests of different nonlinear techniques have been performed and compared to linear techniques. Tensile beams have been used as specimens. Piezoceramics were applied and a high frequency signal transmitted into the specimen simultaneously as a low frequency. Sideband around the high frequency and higher harmonics were then studied to detect nonlinearities. If there are cracks present, the NWMS show nonlinearities by combining the different frequencies shown as sidebands from the high frequency component, and the higher harmonics' amplitudes will increase. NWMS techniques are more sensitive than linear as they can detect smaller cracks. NWMS is faster to evaluate than a linear scanning method, as it can interrogate a complete object in just one measurement, and NWMS is not as limited by complicated geometry of the specimen.

  • 40.
    Haller, Kristian
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Olsson, Ulrika
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Method for Dynamic Automated Laser Measurement applied on Lightweight Test Panels1999Other (Other academic)
    Abstract [en]

    This thesis describes an automated approach to modal testing utilizing a robot control to position a laser vibrometer beam. The method developed reduces the time-consuming data acquisition considerable. A double curved aluminium panel was chosen as test specimen. The selected specimen is suitable because it is hard to measure the dynamic properties of these kind of lightweight structures with accelerometers. Results from the experimental modal analysis were compared to the results given from the FEM calculations. An excellent agreement between the two models was found.

  • 41. Haller, Kristian
    et al.
    Olsson, Ulrika
    Östholm, Stefan
    Method for Dynamic Automated Laser Measurement Applied on Lightweight Test Panels1999Conference paper (Refereed)
    Abstract [en]

    This paper describes an automated approach to modal testing utilizing a robot control to position a Laser Doppler Vibrometer (LVD) [1]. A programmed robotic system was used for the laser positioning. This kept the measurement set correctly identified with respect to the specimen geometry. The communication between the measurement program and the robot, the identification of the candidate robot system, and the mechanical design of the robot-vibrometer interface is described. For verification a sample measurement was performed and results are briefly presented.

  • 42.
    Hansson, Thomas
    et al.
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Laurin, Henric
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Lilja, Johan
    Blekinge Institute of Technology, Department of Mechanical Engineering.
    Prototyputprovning av upphängningssystem2003Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [sv]

    Examensarbetet gick ut på att stötprova ett system för upphängning av kablar och rör i fartyg. Vid stötprovningen monterades upphängningssystemet i en fixtur. Gruppen fick fria händer att utforma fixturen. Med hjälp av Fredy Olssons teorier om produktframtagning utvecklades en fixtur bestående av fyrkantrör. Genom att värdera och selektera bland de lösningar som presenterades i examensarbetet ”Upphängningssystem” BTH-IMA-EX—2000/C-02-SE och andra nytillkomna likvärdiga lösningar, har gruppen kommit fram till och stötprovat ett system, bestående av aluminiumprofiler och vinklar från Bosch Rexroth. Inför varje stötprov har gruppen, för att få en uppfattning om tidsåtgång, arbetsinsats och montagesekvens, utvärderat monteringsarbetet för upphängningssystemet. Vid stötproven har det framkommit, att den svagaste komponenten är de vinkelfästen som sammanbinder systemen. Dessa går till brott redan vid låg belastning och alternativa fästen måste utvecklas. Gruppen har utvecklat och provat två alternativa fästelement. Fästelementen dimensionerades med hänsyn till egenvikt och påkänningar pga. chock och fartygsrörelser. Resultaten från proven har varit lyckade. Det återstår dock fler prov innan en provinstallation i ett fartyg kan genomföras. Prototyperna har dokumenterats med kompletta sammanställningsritningar samt med detaljritningar över tillverkade komponenter för detsamma. Ingående köpekomponenter har dokumenteras med uppgift om komponentslag, föreslagen leverantör, beteckning, huvuddimensioner, prestanda och pris.

  • 43. Hedberg, Claes
    A multi-frequency solution for the Burgers equation1999Conference paper (Refereed)
    Abstract [en]

    A generalization of the single frequency Cole-Mendousse solution for the Burgers equation is shown. The solution is in the same form - a ratio between two Fourier series containing Bessel functions. The input is given as an arbitrary number of frequency components which can have any amplitude, frequency and phase. The solution is valid for any distance.

  • 44. Hedberg, Claes
    Dynamic modelling of some nonlinear materials2002Conference paper (Refereed)
    Abstract [en]

    A nonlinear layer can be a model for a cloud of gas bubbles in a liquid, a crack or split plane in a solid, or contact between two tighted surfaces. Solutions were derived for media under strong load. Numerical calculations based on Preisach-Mayergoyz space description (nonlinear stress-strain relationships typical for solids containing mesoscopic inhomogeneities or defects) have given results like those obtained from LISA (see results by Delsanto). IMVITED. Non-uniform massdistribution of grains immersed into a vibrating fluid create internal forces which is responsible for generation of higher harmonics. Tests on slow dynamics were performed.

  • 45. Hedberg, Claes
    Multifrequency plane, nonlinear, and dissipative waves at arbitrary distances1999In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 106, no 6, p. 3150-3155Article in journal (Refereed)
    Abstract [en]

    A solution for multifrequency plane waves propagating through a dissipative and nonlinear medium is presented. It originates from the well-known Bessel function series ratio for a pure sinusiodal wave, introduced by Cole and Mendousse. The solution is exact. The only limitation, inherited from the single-frequency solution, is the slow convergence of the series when the nonlinearity is very large compared to the dissipation. Otherwise any frequencies, amplitudes and phases can be introduced in the original wave and the solution is valid for any propagated distance.

  • 46. Hedberg, Claes
    Nonlinear Dynamics of Grains in a Liquid-Saturated Soil2002Conference paper (Refereed)
    Abstract [en]

    Known models with huge nonlinear response of grainy media are based on nonlinear stress-strain relationships typical for solids containing mesoscopic inhomogeneities or defects in their structure. Such nonlinear behaviour is well-defined at significant local deformation caused by high applied load, even if the load does not vary in time. However, there exist a different type of nonlinearity which manifests itself due to inertial forces between grains. Such forces appear in a moving noninertial frame of reference, in particular, if a small system of interacting particles is placed into a vibrating fluid. High spatial gradients of internal forces are determined by the non-uniform distribution of mass. These gradients varying in time can excite the internal degrees of freedom. So, even at harmonic vibration of the fluid caused by sound, the nonlinear internal dynamics can be responsible for generation of higher harmonics. As an example of nonlinearity of inertial type, a model of grainy medium is developed where the grains are immersed into a vibrating fluid. The inertial attractive forces have hydrodynamic origin, and the repulsive forces are caused by deformation of colliding grains. Dynamic and stochastic motion is studied, resonances are discovered and nonlinear response is evaluated.

  • 47. Hedberg, Claes
    Parameter sensitivity in nonlinear and dissipative time-reversed acoustics1998Conference paper (Refereed)
    Abstract [en]

    Time-reversed nonlinear acoustics has shown that a propagated signal retains information about the original signal after shock formation and even after merging of shocks. This information is dependent on the accuracy of the measured or calculated data . Presented here is a more detailed analysis of the estimation of dimensionless and real parameters in the problem - the original amplitude, the distance traveled and the dissipation over non- linearity ratio. It is shown that the methods are fairly insensitive to noise.

  • 48. Hedberg, Claes
    et al.
    Arnoldsson, Sven
    Gunnarsson, Rikard
    TWO UTILIZATIONS OF OPEN RESONATOR CONCEPT IN NONDESTRUCTIVE TESTING2003Conference paper (Refereed)
    Abstract [en]

    Two ways in which the concept of open resonator can be used in connection with nondestructive evaluation will be described. In the first, a non-contact transducer's efficiency of transferring energy into an object can be increased by utilizing the resonance of the gap between the transducer and object. By choosing the gap distance, frequency and transducer width a resonant wave appears which will have a considerably larger amplitude at the object surface. Secondly, by fitting the critical parameters of open resonators for thin objects, like extended plates, the wave field inside the object can be localized. Thus some Nonlinear Elastic Wave Spectroscopy methods may be used to determine the location of damage.

  • 49. Hedberg, Claes
    et al.
    Gurbatov, Sergey
    Nonlinear crosstransformation of amplitude-frequency modulation of quasi-monochromatic acoustic signals1998In: Acustica, ISSN 0001-7884, Vol. 84, no 3, p. 414-424Article in journal (Refereed)
    Abstract [en]

    This work is devoted to the investigation of evolution of intense quasi-harmonic signals in the case of infinite acoustic Reynolds numbers. The consideration is based on the zero viscocity limit solution of the Burgers equation, which reduces the Cole-Hopf solution to a "maximum" principle. This limit solution permits an easy way to get the profile of the waves, postition of shocks and their velocities at arbitrary times. The process of transformation of an initial quasi-monochromatic wave into s sawtooth wave is considered. It is shown that the nonlinearity leads to suppression of the initial amplitude modulation and to the transformation of the initial frequency modulation inot a shock amplitude modulation. The amplitude of the low frequency component generated by a quasi-mono-chromatic wave is found. It is shown that the interaction of this component with high frequency waves leads to phase modulation, which increases with distance. The amplitudes of the new components of the spectrum are found. Is is show n that when the value of phase modulation is small, the amplitudes of the satellites do not depend on the distance or the number of harmonics of the primary wave.

  • 50. Hedberg, Claes
    et al.
    Rudenko, Oleg
    Interaction between low and high-frequency Modes in a Nonlinear System: Gas-Filled Cylinder Covered by a movable Piston2003In: Nonlinear dynamics, ISSN 0924-090X, E-ISSN 1573-269X, Vol. 32, no 4, p. 405-416Article in journal (Refereed)
    Abstract [en]

    A simple mechanical system containing a low-frequency vibration mode and set of high-frequency acoustic modes is considered. The frequency response is calculated. Nonlinear behaviour and interaction between modes is described by system of functional equations. Two types of nonlinearities are taken into account. The first one is caused by the finite displacement of a movable boundary, and the second one is the volume nonlinearity of gas. New mathematical models based on nonlinear equations are suggested. Some examples of nonlinear phenomena are discussed on the base of derived solutions.

12 1 - 50 of 79
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