Дисертації з теми "STEEP PROBABILITY"
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Seyedali, Seyed Mohamad. "Getting a Grip on Scrap : Applying Probability and Statistics in Analyzing Scrap and Steel Composition Data from Electrical Steel Production." Thesis, KTH, Materialvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-165413.
Повний текст джерелаReynolds, James Bernard. "Advanced analysis and reliability-based design of steel scaffolding systems." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/11626.
Повний текст джерелаSalgar, Chaparro Silvia Juliana. "Understanding of Microbiologically Influenced Corrosion in Carbon Steel Pipelines: Towards Developing a Methodology to Assess Probability of Failure." Thesis, Curtin University, 2020. http://hdl.handle.net/20.500.11937/81959.
Повний текст джерелаChatterjee, Aritra. "Structural System Reliability with Application to Light Steel-Framed Buildings." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/74879.
Повний текст джерелаPh. D.
Bonneric, Matthieu. "Etude de l'endommagement en fatigue de câbles d'acier sous sollicitations complexes." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLC045.
Повний текст джерелаSteel cables are used as reinforcements in heavy truck tires, in particular to support the forces resulting from the tire pressure and the vehicle's weight. A cable is a set of pearlitic steel wires assembled in helical form on different layers. There are therefore many assembly possibilities to define the cable architecture. The cables are subjected to cyclic loadings during service, resulting in fatigue damage. In a context of reduced fuel consumption and lighter vehicles, understanding the mechanisms involved is thus a major challenge for tire manufacturers, in order to optimize the architecture of cables with respect to fatigue resistance. A cyclic bending test representative of mechanical in-service loading has been developed. The tested specimens are composite layers made of cables aligned within an elastomer matrix. Interrupted tests at different stages of damage followed by ex-situ observations (X-ray tomography, SEM) were performed. A finite element model of the composite layer has been developed in order to understand wire-rubber interactions. The comparison of the observations with the simulations made it possible to understand the kinetics of cable damage during cyclic bending loading.The study of each of the mechanisms likely to contribute to the cable damage has made it possible to explain the better fatigue resistance of the architectures penetrated by the rubber. A stochastic cable fatigue life model based on wire surface defect propagation has been developed
Rota, Bernardo João. "Calibration Adjustment for Nonresponse in Sample Surveys." Doctoral thesis, Örebro universitet, Handelshögskolan vid Örebro Universitet, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-51966.
Повний текст джерелаZarov, Filipp. "Modeling fault probability in single railroad turnouts in Eastern Region, Sweden, with the use of logistic regression models : A step from preventive to predictive preventive maintenance in railway maintenance planning." Thesis, KTH, Transportplanering, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-273639.
Повний текст джерелаSpårväxlar är viktiga delar av järnvägens infrastruktur av två orsaker: infrastruktur och underhåll.För infrastrukturen ger de möjlighet till flexibla tillåter de formulering och grenning av järnvägsnät ochför underhållet konsumerar de en stor del av underhållsbudgeten och de har en framträdande plats iunderhållsplaneringspolitiken och aktiviteterna. Detta beror på att som ett ”maskinellt objekt”, harspårväxeln ofta fel. Problemet blir ännu mer komplicerat, eftersom en spårväxel består av många olikadelar och var och en av dem bryts ner av mycket olika skäl (t.ex. tunganordning vs korsningsdel). Dettaåterspeglas i olika behov av underhållsaktiviteter. Eftersom järnvägarna tvingas hålla alltför storamängder resurser för att utföra akuta reparationer eller för att utföra onödiga schemalagdaunderhållsarbeten i spårväxlar, som inte behöver inspekteras eller repareras. Därför är det svårt attplanera och organisera underhållsaktiviteter för spårväxlarna på ett effektivt sätt. Detta ställer fråganom funktionsfel i spårväxlar kan förutsägas och användas som information till underhållsplaneringsprocessen för att optimera den och utveckla den till en pålitligare förebyggandeunderhållsplanering.Syftet med denna analys är att försöka modellera sannolikheten för olika funktionsfel i spårväxlarsom en funktion av deras huvudsakliga geometriska och operativa egenskaper med användning avlogistiska regressionsmodeller och sedan mata dessa resultat in i underhållsplaneringsprocessen för attoptimera den. För det första var det viktigt att objektifiera järnvägsspårsystemet ochspårväxlarkomponenterna, både vad gäller delar och inbördes förhållanden. Dessutom definieradesprocessen och grundelementen i järnvägsunderhållsplaneringen, samt att argument som motiverarförändring till förebyggande underhållsplaneringsmetoder. Detta gjordes genom en omfattandelitteraturstudie.Grunden i denna analys var fallstudier, som beskrev förhållandet mellan geometriska ochoperationella egenskaper hos spårväxlar och deras förslitning samt riskbaserade modelleringsmetoder ijärnvägsunderhållsplanering. För att skapa analysmodellen användes data från spårväxlar i östraregionen som tillhandahölls av Trafikverket, både ur synpunkten att beskriva de underliggandeorsakerna till spårväxlarsfel och för att formulera en objektorienterad databas lämplig för användning ilogistiska regressionsmodeller. Målet var en logitmodell som beräknade sannolikheten för fel i enspårväxel, som kunde användas direkt i en underhållsplaneringsram, som rangordnar lämpigaunderhållsaktiviteter i spårväxlar.Erhållna resultat visade att även om modellen lider av låg korrelation, konstaterades olika sambandmellan ingående variabler och olika funktionsfel. Vidare visades potentialen hos dessa analysmodelleroch modelleringsstrukturer för att kunna utveckla förebyggande, förutsägbarajärnvägsunderhållsplaner, men det krävs troligtvis ytterligare analys av datastrukturen, specielltangående datakvaliteten. Slutligen presenteras ytterligare möjliga forskningsområden.
Alves, Clever Gama. "Analise de confiabilidade em fadiga : estudo de caso : braço de controle de suspensão automotiva." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264943.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
Made available in DSpace on 2018-08-11T17:15:29Z (GMT). No. of bitstreams: 1 Alves_CleverGama_M.pdf: 6160446 bytes, checksum: 5afa2cd3848388247de70ceee21a3cf8 (MD5) Previous issue date: 2008
Resumo: O presente trabalho descreve um procedimento de aprovação de um braço de controle de suspensão automotiva sujeito a fadiga de alto ciclo, ao mesmo tempo em que propõe uma sistemática alternativa de validação baseada em conceitos e teorias estatísticas de confiabilidade. Nesse aspecto, a pesquisa não só avalia o procedimento seguido pelo fabricante, como também executa comparações gráfico-analíticas de distribuições probabilísticas (normal, lognormal e Weibull) a fim de caracterizar a massa de dados completos e suspensos obtidos em ensaios acelerados de bancada. Um espaço amostral constituído por quatro observações completas da configuração final da peça e oito da inicial, complementado por doze dados suspensos, foi usado para determinar os parâmetros dos modelos. Essa análise levou à escolha do modelo de Weibull bi-paramétrico para o tempo até a falha para as duas configurações em foco. A estimação final dos parâmetros foi feita pelo método da máxima verossimilhança, o qual superou um método alternativo específico para Weibull na comparação com a distribuição referencial de categoria. Dessa forma, calculou-se o ganho efetivo em confiabilidade conseguido com o esforço adicional de desenvolvimento da peça. O teste de hipóteses de Kruskal-Wallis permitiu concluir que as duas configurações realmente possuem performances de durabilidade diferentes. É notável o ganho em confiabilidade obtido por meio das mudanças que levaram à configuração final: em um universo de um milhão de peças, o número de falhas esperadas aos 30.000 ciclos caiu de 96.384 para 5 partes por milhão
Abstract: This dissertation aims at describing a procedure for approval of a suspension control arm subjected to high-cycle fatigue and, simultaneously, at proposing a validation alternative method based on reliability concepts and statistical theories. In that manner, the research provides not only an assessment of the procedure followed by the manufacturer, but also analytical and graphical comparisons of probabilistic distributions (normal, lognormal, Weibull) in order to characterize the set of complete and suspended data from bench accelerated tests. A sample space comprised by four complete final configuration observations and eight complete primary configuration ones, in addition to twelve suspended figures, was the basis for determining the model parameters. Such an analysis led to choose the bi-parametric Weibull for both focused configurations¿ time to failure. The ultimate estimation of the parameters was performed through the maximum likelihood method, which beat a specific alternative method for Weibull when compared with the referential category distribution. Thus, the effective gain in reliability resulting from the product development additional effort was calculated. The Kruskal-Wallis hypothesis testing guided the conclusion that the two configurations actually have different durability performances. It is impressive the gain in reliability brought by the changes that led towards the final configuration: taking an amount of one million parts into consideration, the expected number of failures at 30,000 cycles dropped from 96,384 to 5 parts per million
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
Fox, Clayton D. L. "Modeling Simplified Reaction Mechanisms using Continuous Thermodynamics for Hydrocarbon Fuels." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37554.
Повний текст джерелаGuerchais, Raphaël. "Influence d'accidents géométriques et du mode de chargement sur le comportement en fatigue à grand nombre de cycles d'un acier inoxydable austénitique 316L." Thesis, Paris, ENSAM, 2014. http://www.theses.fr/2014ENAM0020/document.
Повний текст джерелаThe aim of this study is to analyze the influence of both the microstructure and defects on the high cycle fatigue (HCF) behaviour of a 316L austenitic stainless steel thanks to finite element (FE) simulations of polycrystalline aggregates.%The scatter encountered in the HCF behavior of metallic materials is often explained by the anisotropic elasto-plastic behavior of individual grains leading to a highly heterogeneous distribution of plastic slip.Since fatigue crack initiation is a local phenomenon, intimately related to the plastic activity at the crystal scale, it seems relevant to rely on this kind of modeling to evaluate the mechanical quantities.A preliminary numerical study, based on experimental data drawn from the litterature, was conducted on an electrolytic copper using simulations of 2D polycrystalline aggregates. The effect of the loading path and small artificial defects on the mesoscopic mechanical responses have been analyzed separately. Moreover, the predictive capabilities of some fatigue criteria, relying on the mesoscopic mechanical responses, has been evaluated. It was shown that the macroscopic fatigue limits predicted by a probabilistic fatigue criterion are in accordance with the experimental trends observed in multiaxial fatigue or in the presence of small defects.An experimental campaign is undertaken on an austenitic steel 316L. Low cycle fatigue tests are conducted in order to characterize the elasto-plastic behavior of the material. Load-controled HCF tests, using both smooth specimens and specimens containing an artificial hemispherical surface defect, are carried out to estimate the fatigue limits under various loading conditions (tension, torsion, combined tension and torsion, biaxial tension) and several defect radii. To complete the characterization of the material, the microstructure is studied thanks to EBSD analyzes and the cristallographic texture is measured by X-ray diffraction. These experimental data are used to reproduce, with FE simulations, the HCF tests on 2D and 3D microstructures representative of the austenitic steel. The heterogeneity of the mesoscopic mechanical quantities relevant in fatigue are discussed in relation to the modeling. The results from the FE models are then used along with the probabilistic mesomechanics approach to quantify the defect size effect for several loading paths. The relevance, with respect to the experimental observations, of the predicted fatigue strength distributions is assessed
Handika, Nuraziz. "Multi-fissuration des structures en béton armé : analyse par corrélation d'images et modélisation." Thesis, Toulouse, INSA, 2017. http://www.theses.fr/2017ISAT0001/document.
Повний текст джерелаThe modelling of cracking of reinforced concrete using the finite element method requires taking into account, in addition to the concrete damage, three phenomena: the specificity of the steel-concrete bond, the self-stress due to shrinkage, and the probabilistic scale effect due to the heterogeneity of concrete. This research is based on an experimental campaign to obtain the behaviour of the bond and the characteristics of the cracks on structural elements. The technique of digital image correlation was used to observe the spacing and opening of the cracks.The steel-concrete bond is considered in modelling using elastoplastic interface elements based on the experimental results of the pull-out tests. The effects of shrinkage are taken into account via a poro-mechanical framework. Finally, the probabilistic scale effect is integrated into the modelling via a random field method and then a weakest link one. Modelling is applied to the reinforced concrete structural element studied in the laboratory, which makes it possible to quantify the relative importance on cracking of the steel-concrete bond, the stresses induced by shrinkage, and the tensile strength heterogeneity of the material
Saleem, Rashid. "Towards an end-to-end multiband OFDM system analysis." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/towards-an-endtoend-multiband-ofdm-system-analysis(e711f32f-1ac6-4b48-8f4e-58309c0482d3).html.
Повний текст джерелаPiegay, Nicolas. "Optimisation multi-objectif et aide à la décision pour la conception robuste. : Application à une structure industrielle sur fondations superficielles." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0393/document.
Повний текст джерелаDesign in Civil Engineering is usually performed in a semi-probabilistic way using characteristic values which are associated with partial safety factors. However, this approach doesn’t guarantee the structure robustness with regard to uncertainties that could affect its performance during construction and operation. In this thesis, we propose a decision aid methodology for robust design of steel frame on spread foundations. Soil-structure interaction is taken into consideration in the design process implying that the design choices on foundations influence the design choices on steel frame (and vice versa). The proposed design approach uses multi-objective optimization and decision aid methods in order to obtain the best solution with respect to the decision-maker’s preferences on each criterion. Furthermore, sensitivity analyzes are performed in order to identify and quantify the most influencing uncertainty sources on variability of the structure performances. These uncertainties are modeled as random variables and propagated in the design process using latin hypercube sampling. A part of this dissertation is devoted to the effects of uncertainties involved in soil properties on the structure responses and on the design global approach
MISHRA, SAURABH KUMAR. "AN OPTIMIZED PATH PLANNING ALGORITHM BASED ON SOFT COMPUTING." Thesis, 2018. http://dspace.dtu.ac.in:8080/jspui/handle/repository/16354.
Повний текст джерелаLaw, J. R. "Time varying probability of failure of steel floor beams subjected to real fire." Thesis, 1997. https://vuir.vu.edu.au/18185/.
Повний текст джерелаNguyen, Song-Ky-Hieu, and Song-Ky-Hieu Nguyen. "Study of Steel Bridge Maintenance Strategies Using Probability Density Evolution Method and Particle Swarm Optimization." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/36485330997462563976.
Повний текст джерела國立臺灣科技大學
營建工程系
101
Steel bridge structures are the fundamental of transport infrastructure. In nature, steel bridge structures’ performance will decrease over time by many reasons. Bridge maintenance is essential requirement. The life extension of the bridges not only makes the large economic profit but also relieves the financial issue on asset management. Bridge maintenance is carried out to extend the life of the structure and to ensure that it functions as designed. One of challenges in bridge maintenance comes from uncertainty factors which make it difficult to get an accurate prediction of bridge behavior and performance of bridge structures. Therefore, the time-variant reliability model in bridge maintenance is needed. There are several techniques to penetrate the time-variant reliability such as iterative procedure; sampling techniques or Monte Carlo Simulation… This research presents another method called probability density evolution method (PDEM) to solve this issue. PDEM has been researched and developed recently, started with the idea of physical stochastic systems. In general, time-variant reliability model could be treated as a stochastic system. From application of PDEM in generic stochastic system, the probability density function of time-variant reliability in reliability model will be captured. A case study is considered to apply PDEM. Lastly, to fulfillment the problem Stochastic Optimization (PDEM combines with Particle Swarm Optimization algorithm) with uncertainties is used to optimize the maintenance cost by using the result from time-variant reliability as a constraint.
Compagnone, Alberto. "Probabilistc approach for simplified verification methods of resistance of steel frames in fire." Tesi di dottorato, 2020. http://www.fedoa.unina.it/13093/1/COMPAGNONE.pdf.
Повний текст джерелаNuta, Elena. "Seismic Analysis of Steel Wind Turbine Towers in the Canadian Environment." Thesis, 2010. http://hdl.handle.net/1807/24269.
Повний текст джерела(6620411), Leslie E. Campbell. "A Benchmark for Evaluating Performance in Visual Inspection of Steel Bridge Members and Strategies for Improvement." Thesis, 2019.
Знайти повний текст джерелаVisual inspection is the primary means of ensuring the safety and functionality of in-service bridges in the United States and owners spend considerable resources on such inspections. While the Federal Highway Administration (FHWA) and many state departments of transportation have guidelines related to inspector qualification, training, and certification, an inspector’s actual capability to identify defects in the field under these guidelines is unknown. This research aimed to address the knowledge gap surrounding visual inspection performance for steel bridges in order to support future advances in inspection and design procedures. Focusing primarily on fatigue crack detection, this research also considered the ability of inspectors to accurately and consistently estimate section loss in steel bridge members.
Inspection performance was evaluated through a series of simulated bridge inspections performed in representative in-situ conditions. First, this research describes the results from 30 hands-on, visual inspections performed on full size bridge specimens with known fatigue cracks. Probability of Detection (POD) curves were fit to the inspection results and the 50% and 90% detection rate crack lengths were determined. The variability in performance was large, and only a small amount of the variance could be explained by individual characteristics or environmental conditions. Based on the results, recommendations for improved training methods, inspection procedures, and equipment were developed. Above all, establishment of a performance based qualification system for bridge inspectors is recommended to confirm that a satisfactory level of performance is consistently achieved in the field.
Long term, managing agencies may eschew traditional hands-on bridge inspection methods in favor of emerging technologies imagined to provide improved results and fewer logistical challenges. This research investigated the potential for unmanned aircraft system (UAS) assistance during visual inspection of steel bridges. Using the same specimens as in the hands-on inspections, four UAS-assisted field inspections and 19 UAS-assisted desk inspections were performed. A direct comparison was made between performance in the hands-on and UAS-assisted inspections, as well as between performance in the two types of UAS-assisted inspections. Again, significant variability was present in the results suggesting that human factors continue to have a substantial influence on inspection performance, regardless of inspection method.
Finally, to expand the findings from the crack detection inspections, the lower chord from a deck truss was used to investigate variability in the inspection of severely corroded steel tension members. Five inspectors performed a hands-on inspection of the specimen and four engineers calculated the load rating for the same specimen. Significant variability was observed in how inspectors recorded thickness measurements during the inspections and engineers interpreted the inspection reports and applied the code requirements.