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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Caracterização da carne de Tilápia do Nilo (Oreochromis niloticus) submetida à dietas suplementadas com óleo de peixe / Characterization of Nile Tilapia meat (Oreochromis niloticus) submitted to diets supplemented with fish oil

Duarte, Francine Oliveira Souza 28 August 2017 (has links)
Submitted by Franciele Moreira (francielemoreyra@gmail.com) on 2017-09-26T19:24:54Z No. of bitstreams: 2 Tese - Francine Oliveira Souza Duarte - 2017.pdf: 4292507 bytes, checksum: 3019eeefc902c9b91c972c5f4e071422 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Rejected by Luciana Ferreira (lucgeral@gmail.com), reason: O Comitê de Orientação:Profª. Dra . Fernanda Gomes de Paula – EVZ/UFG; Prof. Dr. Cristiano Sales Prado – EVZ/UFG, são os co-orientadores que devem ser digitados na tela seguinte do nome do autor. on 2017-09-27T11:36:49Z (GMT) / Submitted by Franciele Moreira (francielemoreyra@gmail.com) on 2017-09-27T19:20:20Z No. of bitstreams: 2 Tese - Francine Oliveira Souza Duarte - 2017.pdf: 4292507 bytes, checksum: 3019eeefc902c9b91c972c5f4e071422 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-10-02T14:14:17Z (GMT) No. of bitstreams: 2 Tese - Francine Oliveira Souza Duarte - 2017.pdf: 4292507 bytes, checksum: 3019eeefc902c9b91c972c5f4e071422 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-10-02T14:14:17Z (GMT). No. of bitstreams: 2 Tese - Francine Oliveira Souza Duarte - 2017.pdf: 4292507 bytes, checksum: 3019eeefc902c9b91c972c5f4e071422 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-08-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Nile tilapia (Oreochromis niloticus) is one of the most commercially cultivated species in the world, being preferred for its high rusticity and adaptability, fast growth and meat with desirable characteristics, such as low in fat, absence of "Y" spines and firm texture, much appreciated by consumers, which generates good acceptance in the market. To boost animal production, nutritional aids are sought for the animal diet in order to maintain fish health, obtain better rates of zootechnical performance and satisfactory meat quality. Fish oil, a by-product of the fishing industry, has been used as a supplement in animal feed and is recognized for its positive effects also on human health, since it is rich in polyunsaturated fatty acids of the family omega 3, effectively acting in the reduction of incidence of cardiovascular diseases, rheumatic disorders of the nervous system, promoting the strengthening of the immune system. Thus, it is through dietary supplementation of Nile tilapia with fish oil that a greater increase of fatty acids essential to their meat is sought in order to add value to the product and reaffirm it as a functional nutraceutical food, able to provide benefits to the human health, especially by preventing and reducing risks of disease. For this, different levels of inclusion of fish oil in the tilapia ration (5%, 10% and 15%) were tested for periods of 30 and 60 days pre-slaughter. At the end of the experiment, the economic evaluation was carried out, as well as the verification of the blood biochemistry and the indices of productive performance. After the fish were slaughtered and filleted, the steaks were properly packed and stored in freezing temperatures at -40°C for the subsequent physical-chemical analysis of the meat, covering the profile of fatty acids, centesimal composition, mineral elements content, cholesterol, vitamin E, lipid oxidation, color, pH, and texture-related characteristics such as weight loss by thawing, weight loss by cooking, water retention capacity, total and soluble collagen content, and myofibrillar fragmentation index. The treatments with fish oil were significant (P<0.05) only as regards the meat mineral content and the nutritional quality of the fillet lipid profile. For the other attributes, there were positive tendencies to meat quality, since it presented low fat and cholesterol content, a satisfactory centesimal composition for the species, efficient oxidative stability and a lighter fillet coloration with yellowish tones compatible with the taste of the consumer. Regarding the firmness of the fish meat, no influences of the supplemented feed on the analyzes were verified. However, texture improvement was noted due to the increase in CRA, which makes the product more succulent, and greater shear force in products submitted to the cooking process. / A tilápia do Nilo (Oreochromis niloticus) é uma das espécies mais cultivadas comercialmente no mundo, sendo preferida pela sua alta rusticidade e adaptabilidade, crescimento rápido e carne com características desejáveis, tais como baixo teor de gordura, ausência de espinhos em "Y" e de textura firme, muito apreciada pelos consumidores, o que gera boa aceitação no mercado. Para potencializar a produção animal, busca-se auxílios nutricionais para a dieta animal com o intuito de manutenção da saúde dos peixes, obtenção de melhores índices de desempenho zootécnico e satisfatória qualidade da carne. O óleo de peixe, subproduto da indústria pesqueira, tem sido utilizado como suplemento na alimentação animal, sendo reconhecido pelo seus efeitos positivos também na saúde humana, já que é rico em ácidos graxos poli-insaturados da família ômega 3, agindo eficazmente na redução da incidência de doenças cardiovasculares, reumáticas, distúrbios do sistema nervoso, promovendo ainda o reforço do sistema imune. Assim, é através da suplementação dietética de tilápias do Nilo com óleo de peixe que busca-se maior incremento de ácidos graxos essenciais à sua carne, a fim de agregar valor ao produto e reafirmá-lo como alimento nutracêutico funcional, apto a proporcionar benefícios à saúde humana, especialmente prevenindo e reduzindo riscos de enfermidades. Para isso, foram testados diferentes níveis de inclusão de óleo de peixe na ração para tilápias (5%, 10% e 15%) por períodos de 30 e 60 dias pré-abate. Ao final do experimento, realizou-se a avaliação econômica, bem como a verificação da bioquímica sanguínea e dos índices de desempenho produtivo. Após o abate e filetagem dos peixes, os filés foram devidamente embalados e armazenados em temperatura de congelamento a -40°C para posterior análise físico-química da carne, abrangendo o perfil de ácidos graxos, composição centesimal, teor de elementos minerais, de colesterol, de vitamina E, oxidação lipídica, cor, pH, além de características associadas à textura, como perda de peso por descongelamento, perda de peso por cocção, capacidade de retenção de água, conteúdo de colágeno total e solúvel, e índice de fragmentação miofibrilar. Os tratamentos com óleo de peixe foram significativos (P<0,05) apenas quanto ao teor de minerais da carne e a qualidade nutricional do perfil lipídico do filé. Para os demais atributos, observou-se tendências positivas à qualidade da carne, uma vez que esta apresentou baixos teores de gordura e colesterol, composição centesimal satisfatória para a espécie, estabilidade oxidativa eficiente e coloração do filé mais clara à tons amarelados, compatíveis com o gosto do consumidor. Quanto à firmeza da carne dos peixes, não foram verificadas influências da alimentação suplementada sobre as análises realizadas. Notou-se, entretanto, melhoria da textura devido ao aumento da CRA, o que torna o produto mais suculento, e força de cisalhamento maior em produtos submetidos ao processo de cozimento.
32

Desempenho e características de carcaça de juvenis de carpa capim (ctenopharyngodon idella) em resposta a níveis e fontes de proteína da dieta / Growth and carcass characteristics of grass carp (ctenopharyngodon idella) juveniles in response of dietary protein levels and sources

Veiverberg, Cátia Aline 06 February 2009 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / This work was carried out to evaluate the performance and carcass characteristics of grass carp (Ctenopharyngodon idella) juveniles in response to dietary protein levels and sources. For this, two experiments were conducted: the first (80 days), evaluating four crude protein (CP) levels (22, 30, 36 and 44%) and the second (60 days), comparing protein sources in the diet: FCS (porcine meat meal - control); FC: canola meal; FG: sunflower meal and FCG: canola meal + sunflower meal. Both experiments were conducted in a water re-use system composed of 12 tanks (850 L), with three replicates per treatment. In experiment 1, 10 fish by tank (initial weight 153,0±1,5g) were fed 3% of body weight, twice daily, and the experiment 2 was provided ration (2% of biomass) in the morning and forage (Napier grass ad libitum) in the afternoon, to 15 fish by tank (initial weight 54,6±1,0g). Growth parameters (weight, specific growth rate, daily weight gain, relative weight gain and feed conversion ratio) and carcass (carcass and fillet yield, digestive somatic index, hepatic somatic index and visceral fat index, intestinal quotient, protein retention, protein efficiency rate and whole body and fillet protein and fat deposition) were evaluated. Moreover, the proximate composition (moisture, ash, fat and protein) in fillet and whole fish and blood parameters (glucose, total triglycerides, total cholesterol and total protein in both experiments and hematocrit in Experiment 1) were also evaluated. In experiment 2 was also determined the daily consumption of forage and the instrumental color. In experiment 1, linear positive effect of protein level for all growth variables was observed. However, the same effect was observed to whole body and fillet fat deposition, triglycerides and total cholesterol in serum, indicating that the protein from the diet was used as energy source. To feed conversion ratio and fat in whole fish, the effect was quadratic, with maximum response with 40.6 and 37.1% CP, respectively. Protein retention, protein efficiency ratio, protein deposition in whole body and fillet and hematocrit also showed linear positive effect, while the other parameters were not affected. In experiment 2, the growth parameters and the daily consumption of forage (1.24 to 2.11% of body weight) did not differ among the treatments. About proximate composition of whole fish, higher fat content and lower protein content, besides fillet ash, were obtained in the treatment FCG. The diet FCS presented the highest values of serum protein, triglycerides and total cholesterol. The fillet yield was higher in the treatments FCG and FC, while the digestive somatic index was higher in treatment FG and FCG. In the instrumental evaluation of color, the fillets from FCS and FCG diets showed higher value of L (brightness), differing only treatment FC. The other parameters did not differ among them. Based on this results, we can conclude that: the minimum protein level for maximum growth of grass carp in the growing phase, with practical diets, is 44%; the variation in dietary protein level promotes changes in metabolism of juvenile grass carp, reflected in hematological and carcass parameters; canola meal and sunflower meal can be used in diets for grass carp growing phase, when supplemented with limiting essential amino acids, without compromising growth. / Este trabalho foi conduzido com o objetivo de avaliar o desempenho produtivo e qualidade de pescado de juvenis de carpa capim (Ctenopharyngodon idella) em resposta a níveis e fontes de proteína da dieta. Para isso, foram conduzidos dois experimentos: o primeiro, com 80 dias, avaliando quatro níveis de proteína bruta (22, 30, 36 e 44%) e o segundo, com 60 dias, avaliando fontes protéicas na dieta, em combinação com farelo de soja: FCS: farinha de carne suína; FC: farelo de canola; FG: farelo de girassol e FCG: farelo de canola + farelo de girassol. Ambos os experimentos foram conduzidos em sistema de recirculação de água com temperatura controlada, composto de 12 unidades experimentais (850 L), com três repetições por tratamento. No experimento 1, 10 animais por unidade experimental (peso inicial 153,0 ± 18,2g) foram alimentados com ração (3% da biomassa) duas vezes ao dia. No experimento 2, foram utilizados 15 animais por unidade experimental (peso inicial 54,7 ± 7,8g), alimentados com ração (2% da biomassa) pela manhã e capim elefante (à vontade) à tarde. Foram avaliados os parâmetros de crescimento (peso, taxa de crescimento específico, ganho em peso diário e relativo e conversão alimentar aparente) e de carcaça (rendimento de carcaça e filé, índices digestivossomático, hepatossomático e de gordura visceral, quociente intestinal, coeficiente de retenção protéica e deposições de proteína e gordura corporal e no filé). Além disso, a composição centesimal (umidade, cinzas, gordura e proteína) no filé e no peixe inteiro e os parâmetros sangüíneos (glicose, triglicerídeos totais, colesterol total e proteínas totais nos dois experimentos e hematócrito no experimento 1) também foram avaliados. No experimento 2 também foi determinado o consumo diário de forragem e a medida instrumental da cor. No experimento 1, houve efeito linear positivo do nível de proteína para todas as variáveis de crescimento. Entretanto, o mesmo efeito foi observado para a deposição de gordura corporal e no filé, triglicerídeos totais e colesterol total no soro, indicando que a proteína proveniente da dieta estava sendo utilizada como fonte de energia. Para conversão alimentar aparente e gordura no peixe inteiro, o efeito foi quadrático, com ponto de máxima em 40,6% de PB e 37,1%, respectivamente. Coeficiente de retenção protéica, taxa de eficiência protéica, deposição de proteína corporal e no filé e hematócrito também apresentaram efeito linear positivo. No experimento 2, os parâmetros de crescimento não diferiram estatisticamente entre os tratamentos. O consumo de forragem variou entre 1,24 e 2,11% do PV por dia, não diferindo entre os tratamentos. Na composição centesimal do peixe inteiro, maior teor de gordura e menor teor de proteína foram obtidos no tratamento FCG, bem como para cinzas no filé. A dieta FCS foi a que apresentou maiores valores de proteínas, triglicerídeos e colesterol total circulantes. O rendimento de filé foi maior nos tratamentos FC e FCG, enquanto o índice digestivossomático foi maior nos tratamentos FG e FCG. Na avaliação instrumental da cor, os filés obtidos dos tratamentos FCS e FCG apresentaram maior valor de L (luminosidade), diferindo apenas do tratamento FC. Com base nos resultados obtidos, pode-se concluir que: o nível mínimo de proteína para o máximo crescimento da carpa capim na fase de recria, com dietas práticas, é de 44%; a variação do nível de proteína da dieta promove alterações no metabolismo dos juvenis de carpa capim, refletido nos parâmetros sangüíneos e de carcaça; farelo de canola e farelo de girassol podem ser utilizados em dietas para recria da carpa capim, quando for feita a suplementação com lisina e forragem, sem comprometer o crescimento.
33

Konstrukce hydraulické štípačky dřeva / Construction of hydraulic wood-splitting machine

Šimčík, Jaroslav January 2010 (has links)
Bc. Jaroslav Simcik Construction of hydraulic wood-splitting machine DP, Institute of production machines, systems and robotics, 2010, p. 60, fig. 30, appendices 7, This master ´s thesis is concerned with the wood-processing technology with a focus on the construction of hydraulic wood splitter machine with a force 120 kN.
34

Návrh palety automatického parkovacího systému / Design of flat pallet for automatic parking garage

Osmík, Jiří January 2011 (has links)
Design of flat pallet for automatic parking garage. Parking and description of automatic parking systems. Welding and weldability of materials. Electric arc welding and welding by melting electrode in protective gas by MIG/MAG method, welding instruments. Design of parking palette calculation and calculation this palette by MKP method. Process of drawing documentation for parking palette. Design of welding process and WPS. Description of annealing and zinc coating. Economic-technical analysis of palette for automatic parking system production.
35

Srovnání MKP modelů spojů / Comparision of FEM models of joints

Hlaváč, Martin January 2011 (has links)
This thesis deals with the comparison of alternative models of the simplified joints used in the FEM models of complex models with detailed joint details. This is essentially a screw connection with dowel bolt and standard bolt, weld connection "T" and overlap weld connection. Individual connections are compared in the simulation results of matching models.
36

Napěťová, deformační a spolehlivostní analýza svařované rámové konstrukce / Stress, deformation and safety analysis of the welded frame construction

Král, Jiří January 2013 (has links)
Diploma thesis deals with creating of computational model of welded frame to perform strain-stress analysis. Thesis aims at verification of welded joints and their possible changes. The next goal is to compare stresses obtained from calculation with respect to welding standard and FEM analysis.
37

Dieta, aspectos bromatológicos e parasitológicos em uma espécie de peixe não-nativa no reservatório de Jupiá, alto rio Paraná

Garves, José Daniel Soler. January 2020 (has links)
Orientador: Igor Paiva Ramos / Resumo: Empreendimentos hidroelétricos podem desencadear alterações no ciclo hidrológico, desequilíbrio dos ecossistemas aquáticos e facilitar a introdução de espécies de peixes não-nativas. Contudo, essas espécies também podem apresentar grande representatividade na pesca artesanal e esportiva, tornando-se uma importante fonte de renda local. Dessa forma, o estudo de espécies não-nativas, suas origens, hábitos e posições tróficas, além de suas habilidades que garantem a permanência e o sucesso no estabelecimento em novos ambientes, são relevantes. Dentre tais espécies não-nativas, Geophagus sveni destaca-se como uma das espécies mais importantes para pesca artesanal na região Noroeste do estado de São Paulo. O presente trabalho teve como objetivo caracterizar e correlacionar a composição alimentar, composição bromatológica do tecido muscular, perfil de ácidos graxos do tecido muscular e hepático, além de identificar possíveis parasitos musculares em G. sveni nos períodos chuvoso e seco, no reservatório de Jupiá, alto rio Paraná, Brasil. Foram realizadas duas coletas, uma ao final do período chuvoso (março/2018) e outra ao final do período seco (agosto/2018), no reservatório de Jupiá (20°30'33.4"S 51°27'19.7"W). Os espécimes coletados foram eutanasiados e, em seguida, tiveram mensuradas massa total, comprimento padrão e o sexo determinado visualmente. Geophagus sveni apresentou hábito alimentar detritívoro, além de plasticidade e oportunismo trófico. Sua composição alimentar foi sign... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Hydroelectric developments can trigger changes in the hydrological cycle, imbalance in aquatic ecosystems and facilitate the introduction of non-native fish species. However, these species can also be highly representative in artisanal and sport fishing, becoming an important source of local income. Thus, the study of non-native species, their origins, habits and trophic positions, in addition to their skills that guarantee permanence and success in the establishment of new environments, are relevant. Among these non-native species, Geophagus sveni is provided as one of the most important species for artisanal fisheries in the Northwest region of the state of São Paulo. This study aimed to characterize and correlate the food composition, the bromatological composition of muscle tissue, the fatty acid profile of the muscle and liver tissue, in addition to identifying possible muscle parasites of Geophagus sveni in the rainy and dry periods, in the Jupiá reservoir, on the Paraná River, Brazil. Two collections were made, one at the end of the rainy period (March/2018) and another at the end of the dry period (August/2018), at the Jupiá reservoir (20°30'33.4"S 51°27'19.7"W). The collected specimens were euthanized and, afterwards, total mass and standard length were measured, as well as sex determined visually. Geophagus sveni presented detritivorous eating habits, in addition to plasticity and trophic opportunism. Their food composition was significantly different only between t... (Complete abstract click electronic access below) / Mestre
38

A Neural Network Based System to Recognize, Detect and Locate Sealworm Parasitic Infestations on Cod Fish Fillet Images / Neural Network System to Recognize Parasites on Fish Images

Aryee, Emmanuel 04 1900 (has links)
In this project, an investigation of a neural network based system is used to examine the following: a) the possibility and practicability of analysing and recognising parasites/sealworms on a parasite/sealworm infested cod fish images, b) the most efficient but robust way of presenting data to the neural network for efficient training and generalisation. The basic problem is to automate the sorting of sealworm infested cod fish from good normal cod fish using a neural network based system. The generalised back propagation supervised learning algorithm is used and both steepest descent and conjugate gradient methods are investigated. Various data representation schemes in unprocessed and processed formats before presentation for training of the neural network, are also examined. Finally the level of recognition achieved by the neural network when presented with the cod fish images is computed. Thus in this project an attempt is made to analyse and find the best components for solving the basic problem and then use this information to develop a neural network based system to recognise, detect and locate parasite/sealworms on cod fish images. / Thesis / Master of Science (MSc)
39

Systematic Analysis and Comparison of Stress Minimizing Notch Shapes : Obtaining a stress concentration factor of Kt=1 without FEM-Code

Ciomber, Isabelle, Jakel, Roland 08 May 2014 (has links) (PDF)
Als Stand der Technik sind einfache, kreisförmige Verrundungen zur Reduktion von Kerbspannungen an Querschnittsübergängen bekannt, für die aus Tabellenwerken / Diagrammen in der Literatur die Formzahl einfach abgelesen werden kann. Die Effizienz der Spannungsreduktion solcher Lösungen ist jedoch sehr begrenzt. Ziel der Arbeit ist es daher, dem Konstrukteur bzw. Berechnungsingenieur ein Verfahren in die Hand zu geben, mit dem er für Standardquerschnittsübergänge und Standardlastfälle "Nicht-Kreiskerben" ohne teure und zeitaufwendige FEM-Analyse einfach durch Nutzung geeigneter Formzahldiagramme auslegen kann. Dabei sind sogar Formzahlen von nahezu eins möglich, d.h., in der "Kerbe" bleibt praktisch nur noch die Nennspannung übrig. Die Präsentation ist zweitgeteilt: Im ersten Teil werden die Arbeitsmethoden bzw. Softwarefunktionen und verwendeten Softwarewerkzeuge vorgestellt: Dies sind die Programme Creo Parametric als vollparametrisches CAD-Werkzeug und Creo Simulate als p-FEM-Programm der Parametric Technology Coprporation (PTC). Der zweite Teil der Präsentation beschreibt den Gültigkeitsbereich sowie die untersuchten Kerbgeometrien: Die einfache kreisförmige Verrundung als Stand der Technik, die Zwei-Radien-Kerbe, die Baud-Kurve, die Methode der Zugdreiecke nach Claus Mattheck, die elliptische Kerbe sowie die konische Rundung als generalisierte elliptische Kerbe. Es wird kurz eine Bibliothek vorgestellt, mit der solche Kerben einfach ausgelegt werden können, d.h. Ihre exakte Geometrie festgelegt sowie die zugehörige Formzahl αk bestimmt werden kann. / Circular (one-radius) fillets are known as state-of-the-art for reducing notch stresses at cross section transitions. The stress concentration factor Kt of such geometries can be read out from diagrams/tables given in the literature. However, the efficiency of stress reduction of circular notches is very limited. The goal of the work therefor is to present a method for the designer/analyst how to design non-circular notches/fillets just by using suitable Kt-diagrams without time-consuming and expensive FEM analyses. Kt-numbers of nearly one are possible, that means in the "notch" just the nominal stress appears and no stress concentration takes place. The presentation has two parts: Part one describes the working methods and software functions as well as software tools: Creo Parametric as fully-parametric CAD program and Creo Simulate as embedded p-FEM-tool from Parametric Technology Corporation (PTC) have been used. The second part describes the range of validity and the examined notch geometries: The one-radius fillet as state-of-the-art, the two-radii filet, the Baud-curve, the method of tensile triangles from Claus Mattheck, the standard elliptical fillet and the conical round as generalized elliptical fillet. A notch layout library is shortly presented that allows to design such fillets, that means exactly determine the notch geometry and the related stress concentration factor Kt.
40

Beräkningsmetoder för verifiering av svetsar med inriktning på PWT / Calculation methods for welding verification with focus on PWT

Petersson, Viktor, Gustafsson, Johan January 2019 (has links)
Stål är ett material som används i olika byggnadskonstruktioner. I de byggnadskonstruktioner som utsätts för upprepade belastningar kan utmattning ske i materialet. Utmattning leder till permanenta skador i form av sprickbildning och slutligen brott. I svetsade konstruktioner är det ofta svetsar som har den lägsta utmattningsstyrkan. För att förbättra en svets utmattningsstyrka finns efterbehandlingsmetoder som benämns Post Weld Treatment (PWT). Idag används den beräkningsmetod som är föreskriven i Eurokod vid verifiering av svetsar. Beräkningsmetoden är förenklad och kan underskatta objektets livslängd med hänsyn till utmattning. Syftet med arbetet är att studera olika dimensioneringsmetoder som behandlar utmattningsbelastade svetsar samt hur tillämpning av PWT kan förbättra en typsvets livslängd. Målet med arbetet är att studera en typsvets och visa skillnaden i antalet lastcykler mellan beräkningsmetoderna samt hur många lastcykler samma typsvets förväntas öka med PWT. Teorin och resultaten utgår från vetenskapliga artiklar, litteraturstudier och enfallstudie som behandlar både en genomsvetsad stumsvets samt en kälsvets lokaliserade på en I-balk. Resultatet pekar mot att den metod som används idag underskattar livslängden och att PWT kan markant kan förbättra en svetsutmattningsstyrka. / Steel is a material used in various building structures. Fatigue can occur in the material if building structures is exposed for repeated loads. Fatigue leads to permanent damages such as crack initiations and fracture. It is common that welds in welded structures have the lowest fatigue strength. A welds fatigue strength can be improved with treatments termed Post Weld Treatment (PWT). Today a welds fatigue strength is verified with a method described in Eurocode. The calculation method is simplified which can underestimate the objects number of lifecycles regarding fatigue. The purpose with this essay is to study different structural design methods for fatigue exposed welds and how many lifecycles a typeweld will increase when applying PWT. The goal with this essay is to study a typeweld and calculate the number of lifecycles between the calculation methods and to show how many lifecycles the same type weld will increase when applying PWT. The results and theory are based on scientific articles, literature studies and a casestudy which both contains a through welded butt weld and a fillet weld placed on an I-beam. The results points at that the calculation method that is used today underestimates the number of lifecycles and that the number of lifecycles increased significant after PWT.

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