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In the design of piping systems the importance of the pipe bend is well established. Recent publications have been increasingly concerned with the effect of end constraints on the behaviour of smooth pipe bends. This has been aimed almost exclusively at in-plane bending, there being no serious attempts at the solution to out-of-plane bending. In PART (1) of this thesis a theoretical solution is presented for the out-of-plane bending of linear elastic curved pipes with rigid flanges. The analysis employs the theorem of minimum total potential energy with suitable kinematically admissable displacements in the form of fourier series. Integration and minimisation is performed numerically. Results are given for a wide range of practical bend geometries. A comparison with previous theoretical predictions highlights the inadequacy of these earlier solutions. The present results are shown to be in favourable agreement with results from tests conducted by the author and more recent results using a different solution procedure. Work in the creep of pipe bends necessitates a substantial amount of experimental work and expertise. Most publications dealing with the creep of pipe bends under bending loads fail to present much information on this aspect. In PART (2) of this thesis a general description is given of an experimental creep programme on pipe bends. The measurement of strain at elevated temperature was accomplished using the CERL-PLANER capacitance strain gauge. It is shown that the application of this gauge to pipe bends requires particular techniques if meaningful results are to be obtained. The results of development work arising from other problems encountered during the test programme are also presented. These include the measurement of displacement and distortion at elevated temperature and the provision of an efficient and novel heating system.

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Enligt statistiken år 2010 fanns det 26 individer sett från en grupp på 100.000 som var tilldelade oxygenbehandling i hemmet. Oxygenbehandlingen tillför en bestämd mängd oxygen till bäraren då möjligheten att själv förse sig med rätt mängd för överlevnad hämmats. Den dominerande sjukdomen till oxygenbehandling i hemmet är KOL, kroniskt obstruktiv lungsjukdom. Som namnet antyder är det en kronisk sjukdom som ger inflammatoriska förändringar i lungans bronkioler. Dessa förändringar minskar andningsytan vilket resulterar i att individens andningskapacitet reduceras. Projektet använde metoder från dynamisk produktutveckling med användaren i fokus. Detta för att få fram en funktionell prototyp som kunde användas utav avsedd målgrupp och uppfylla det syfte, mål och krav som ställdes på projektets resultat. En viktig komponent som projektet därför arbetade med var insamling av data. För detta användes olika metoder som kunde tillskaffa sig information från både användare och förskrivare av oxygenbehandling.  Samtliga av de metoder som användes var beprövade sedan tidigare och projektet kunde därför med fördel genomföra intervjuer, observationer, matrisuppställningar, riskanalyser samt användartester på patienter med oxygenbehandling. Prototypen som togs fram i projektet resulterade i att avsedd målgrupp kunde utföra testmoment på den utan att det förekom risker med användandet. Resultatet uppfyllde därför syftet och målet med projektet som riktade sig mot att patienter skulle få möjlighet till att förflytta den syrgasslang som används vid oxygenbehandling. Vidare kunde slutsatsen dras att resultatet uppfyllde patienternas önskemål om att ta fram en möjlighet till förflyttning av syrgasslangen i hemmet samtidigt som det besvarade de frågeställningar som projektet strävade efter att besvara. Det fanns inga befintliga lösningar på det problem som beskrevs i projektet och det gav möjlighet att framställa en första prototyp som uppfyllde syftet och målet. / According to statistics, in 2010 there were 26 individuals seen by a group of 100,000 who were depending in home oxygen therapy (HOT). Oxygen treatment adds a certain amount of Oxygen to the patient because the ability to breathe correctly and sufficiently is negatively affected. The dominant disease that leads to HOT is COPD, chronic obstructive pulmonary disease. As the name suggests, it is a chronic disease which gives inflammatory changes to the lung bronchioles. These changes affect the breathing surface which results in that the individuals’ respiratory capacity becomes reduced. The project used methods from dynamic product development with the user in focus. This to obtain a functional prototype that could be used by the target group and to fulfill the purpose, goals and requirements set for the project's results. An important component of the project therefore was to work with the collection of data. For this, various methods were used to obtain information from users as well as prescribers of HOT. All of the methods used have been tested earlier and proven reliable. This project collected information from interviews, observations, matrix arrays, risk analysis and usability testing in patients with HOT. The prototype developed in the project resulted in that the target group could perform live test without any risks during testing. The results showed that the aim and objective for the project were fulfilled, expressed in that patients would be able to move the oxygen tube used in HOT. It was further concluded that the results fulfilled the patients' desire and opportunity to move the Oxygen tube in their home and at the same time answered the questions that the project was to answer. There were no existing solutions to the problem which is included in the project, but it was possible to develop a first prototype that met the purpose and object of the project.

The use of single mitre oipe bends, in pipework and ducting, is evident in many areas of industry. However, it has been recognized that a theory which embraced all aspects of the elastic behaviour o£ single mitre bends does not exist. The present investigation demonstrates ~~e feasibility of using finite element methods for such a task. After an extensive series of 'verification comparisons' with experimental results obtained by the aUL~or and also with D~eoretical and experimental results available in the literature, a study of a wide range of ~~reinforced and fully fixed mitres was carried out. As a result of this study, useful design curves illustrating ~~e variation of stress concentration factor and flexibility factor, WiL~ radius to ~~ickness ratio and mitre angle, were produced for an inplane bending load. The above verification comparisons included in-plane bending, out-ofplane nending, torsion, internal pressure and transverse force loadings. An investigation into the effect of leg length and material properties on ~~e behaviour of mitre bends was also conducted. As a result of these studies, the limitations of currently used design Code formulae became evident. Possible difficulties in the numerical solution of thin shell problems are highlighted. In addition, a study of various methods of modelling shell intersections is reported. The most comprehensive review of literature to date, on all aspects of mitre bend behaviour, is presented in the Supplement to this thesis.

The importance of smooth pipe bends in design of piping systems is well established. Recent publications have been increasingly concerned with the effect of end constraints on the behaviour of smooth bends but there have been relatively few attempts at a solution to the problem. The divergence between the results of those which do exist tend to confuse the picture for pipework designers. The present thesis is aimed at clarifying the situation. After an historical review of the literature on smooth bends, a theoretical analysis is formulated for the in-plane bending of linear elastic curved pipes with rigid flange terminations. The method employs the theorem of minimum total potential energy with suitable kinematically admissible displacements in the form of fourier series. Integration and minimisation is performed numerically, thereby permitting the removal of several of the assumptions made by previous authors. Results are given for a wide range of practical bend geometries. These are compared with the previous theoretical predictions, highlighting the problems in same earlier works and substantiating more recent results using different solution procedures. During the development of the theory several possible simplifications to the method are examined. The theoretical predictions are shown to be in favourable agreement with published experimental data and with results from tests performed by the author. The approach is extended to examine the behaviour of smooth bends with connected tangent pipes under in-pane bending. The tangent pipes can be of any length and are assumed to be terminated by rigid flanges. Comprehensive results are given for bends with tangent pipes ot length greater than one pipe circumference. Finally, possible extensions ot the solution procedure to other configurations and loadings are discussed.

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No description available.