In Diesel engine blocks properties such as tensile strength, heat conductivity, sound damping, engine vibration and noise are strongly influenced by graphite shape and volume percent in the matrix microstructure. In this study, the engine blocks were produced at ELBA Basin&ccedil / li D&ouml / k&uuml / m Od&ouml / ksan Cast iron foundry in Osmaneli Turkey by performing casting into furan resin sand and preparing cast iron liquid alloy in induction furnace that were treated with Mg by using ladle method. The main purpose of this study is to achive 0 &ndash / 25% volume nodularity and remaining is compacted graphite in the produced engine blocks. The shape and volume percent of graphite particles were characterized by an image analyze system. In the first part of this work, after the diesel engine blocks were produced at ELBA Basin&ccedil / li D&ouml / k&uuml / m Od&ouml / ksan Cast iron foundry in Osmaneli Turkey, the blocks were cut and samples were obtained from 14 different thicknesses of diesel engine blocks. Afterwards, the samples were examined under optical microscope, Soif XJP-6A. The nodularity and compacted graphite values were obtained numerically with the help of Materials Plus image analyzer systems, which is attached to the optical microscope. v In the second part of the study, the diesel engine blocks which are produced at Od&ouml / ksan were examined by ultrasonic test that was done by using USM 35 flaw detector test machine. Solidification &ndash / time and temperature &ndash / time simulations were also done by using NovaCast NovaFlow simulation code. Finally mathematical formulas for 13 different thickness of diesel engine blocks were obtained by using excel linest code. The compacted graphite volume percent observed at different sections of the diesel engine blocks were found to be a function of cooling rate and chemical composition. Best results were obtained when chemical Mg/S ratio was approximately 1 and C.E.V. was between 4.40 &ndash / 4.50.

Orientador: Kamal Abdel Radi Ismail / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-23T08:47:57Z (GMT). No. of bitstreams: 1 SousaFilho_LourivalMatosde_D.pdf: 17246436 bytes, checksum: 4f99e2f233216584c3570917e55b69c6 (MD5) Previous issue date: 2013 / Resumo: O processo de solidificação de um material de mudança de fase ao redor de um tubo curvo resfriado é estudado numericamente com vistas à aplicação em sistemas de armazenamento de calor latente. A influência da convecção natural na fase líquida foi levada em consideração. O modelo matemático foi formulado em termos das variáveis primitivas, sendo este bidimensional e transiente. O método dos volumes finitos foi empregado para discretizar o sistema de equações diferenciais que governam o fenômeno físico, resultando em um sistema de equações algébricas lineares. Para fixar e tornar regular a frente de solidificação que se desloca ao longo do tempo, foi aplicada a técnica de transformação de coordenadas. O tratamento do termo transiente foi discretizado em uma formulação implícita para as equações da conservação, enquanto, a equação do balanço de energia na fronteira sólido-líquido, foi obtida explicitamente. Os resultados numéricos da frente de solidificação obtidos pelo presente modelo foram comparados com os resultados disponível na literatura, apresentando uma boa concordância. Resultados para alguns parâmetros fundamentais no dimensionamento de sistemas térmicos também foram obtidos e discutidos neste estudo. Os resultados mostram que os parâmetros como temperatura da parede, temperatura inicial do PCM líquido e razão de curvatura tem influencia significativa sobre a posição da interface, velocidade da interface, massa solidificada e tempo completo da solidificação / Abstract: The solidification process of a phase change material around a curved tube is cooled numerically investigated in order to apply to systems of latent heat storage. The effect of natural convection in the liquid phase was taken into account. The mathematical model was formulated in terms of the primitive variables, and this two-dimensional transient. The finite volume method was used to discretize the system of differential equations that govern the physical phenomenon, resulting in a system of linear algebraic equations. To fix and become regular solidification front which moves along the time technique was used to transform coordinates. The treatment of the transient term was discretized in implicit formulation for the equations of conservation, while the equation of energy balance in the solid-liquid boundary was obtained explicitly. The numerical results of the solidification front obtained by this model were compared with results available in the literature, showing good agreement. Results for some key parameters in the design of thermal systems were also obtained and discussed in this study. The results show that parameters like wall temperature, initial temperature of the liquid PCM and curvature ratio has a significant influence on the position of the interface, interface speed, mass, solidified and completed solidification time / Doutorado / Termica e Fluidos / Doutor em Engenharia Mecânica

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The present-day automotive industry is striving to design lightweight components by optimizing the design for minimization of weight. The topology optimization is used widely for the design of lightweight components. The casting process is time and cost effective for mass production and widely adopted within the automotive industry. Generally, castability is not considered in the weight optimization process. These weight optimized components are optimized once again in the later stage for cost-effectiveness in the casting process. The modified design usually weighs more than the weight optimized design. The design can be optimized for weight and castability simultaneously in the early stage of design and this thesis report presents an optimization process for the same. The optimization process presents effective usage of the topology optimization to design lightweight components without compromising castability. It is a three-step process where thetopology optimization is integrated with solidification simulation along with DFX -castability evaluation. The reliability of the conceptual design is predicted based on the mapping of solidification and stress hotspots. The process is implemented to design three components of Scaniatruck and weight is reduced by 15% to 25%. / Dagens bilindustri strävar efter att utforma lätta komponenter genom att optimera designen för att minimera vikt. Topologioptimering används i stor utsträckning för design av lätta komponenter. Gjutningsprocessen är tids-och kostnadseffektiv för massproduktion och allmänt vedertagen inom bilindustrin. Generellt ingår inte gjutbarhet i viktoptimeringsprocessen. Dessa viktoptimerade komponenter optimeras igen i ett senare skede för kostnadseffektivitet vid massproduktion. De flesta gånger är viktoptimerade koncept modifierade för att erhålla kostnadseffektivitet vid gjutning genom att lägga till extra vikt. I den här rapporten presenteras enoptimeringsdriven designprocess för att få pålitlig lättviktsgjutbar design. Optimeringsprocessen presenterar effektiv användning av topologioptimering för att utformalätta komponenter utan att kompromissa med gjutbarheten. Det är en trestegsprocess där topologioptimering integreras med förstärkningssimulering tillsammans med utvärdering avDFX-sårbarhet. Tillförlitligheten hos den konceptuella designen förutses baserat på kartläggningav stelningen och spänninggskoncentrationer. Processen är implementerad för att optimera utformningen av tre komponenter i Scania-lastbilar och vikten minskas med 15% till 25%.

La thèse CIFRE s'est déroulée dans un contexte de métallurgie industrielle et de simulation numérique. La modélisation de la solidification, via l'équation de la chaleur et avec des méthodes de réduction de modèle, était un objectif majeur. L'entreprise Montupet, spécialisée dans la fonderie d'aluminium, est le porteur du projet et financeur de la thèse. L'université de Technologie de Compiègne (UTC) a réalisé l'accompagnement académique. La méthode PGD “Proper General Decomposition”, basée sur une séparation de variables, est l'objet de nombreuses recherches. Nous avons proposé, concernant des propriétés matériaux non-linéaires, une discrétisation spatio-temporelle des matrices matériaux. Avec une formulation en température, sans chaleur latente, les gains sont élevés. L'introduction de la chaleur latente réduit fortement les gains. Nous formulons l'hypothèse que la difficulté de convergence de la méthode PGD dans le cas de la solidification repose sur une formulation en température inadaptée. Nous décidons d'opter une formulation en enthalpie. Il s'avère que cette formulation offre des perspectives encourageantes, mais nécessite encore beaucoup de développements. En parallèle de ces développements, un séjour de 5 mois aux États-Unis a été réalisé afin d'obtenir une meilleure caractérisation de la fraction solide. La recherche s'est portée sur l'évolution de la fraction solide en fonction de la vitesse de refroidissement. Sous réserve de mesures complémentaires, les essais ont mis en évidence une modification de la courbe de fraction solide en fonction de la vitesse de refroidissement, notamment un agrandissement de l'intervalle de solidification. / The PhD Thesis was carried out in a metallurgy and numerical simulation environment. The main topic was to model solidification, thought heat equation formulation and reduced order model PGD resolution. Montupet, specialized in aluminium alloys foundry hold and financed the project, the Université de Technologie de Compiègne did the acadernic supervising. The PGD method "Proper General Decomposition" is a hot topic based on variable separation. We proposed, regarding the non-linear materials, a space-time discretization of material matrix. With a temperature formulation, without latent heat, gains are high. With latent heat, gains fall drastically. We proposed the hypothesis that temperature could be an inadapted formulation. We decided to use the enthalpy formulation. This formulation offers good perspectives but needs more developments. During the thesis, five months were spent in the USA to get a better caracterisation of the solid fraction, particularly its variation in function of the cooling rate. Under reservation, the samples show a modification of solid fraction curves and particularly a change of solidification interval in function of cooling rate.