Doutorado em Engenharia Mecânica

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    Estimation Problems In Advective-Diffusivereactive Phenomena Using Meshless Numerical Methods Combined With Bayesian Inference
    (Universidade Federal do Espírito Santo, 2024-03-22) Dalla, Carlos Eduardo Rambalducci; Dutra, Júlio Cesar Sampaio ; https://orcid.org/0000-0001-6784-4150; http://lattes.cnpq.br/5331990513570911; Colaço, Marcelo José; https://orcid.org/0000-0002-8020-6222; http://lattes.cnpq.br/4953372732452626; Silva, Wellington Betencurte da ; https://orcid.org/0000-0003-2242-7825; http://lattes.cnpq.br/6900925458823632; https://orcid.org/0000-0002-8078-6554; http://lattes.cnpq.br/2522314513419213; Neto, Carlos Friedrich Loeffler; https://orcid.org/0000-0002-5754-6368; http://lattes.cnpq.br/3102733972897061; Lara, Luciano de Oliveira Castro ; https://orcid.org/0000-0003-1329-2957; http://lattes.cnpq.br/1675675424615229; Lamien, Bernand; https://orcid.org/0000-0003-1665-26-20; http://lattes.cnpq.br/3496682177555473; Costa, José Mir Justino da ; https://orcid.org/0000-0001-5719-4377; http://lattes.cnpq.br/2396817509327075
    The mathematical modeling of advective-diffusive-reactive phenomena finds numerous applications in various scientific fields, such as the transport of pollutants and adsorption columns. Mesh reduction techniques have proven efficient and have been gaining prominence in the literature. However, despite all the progress observed, some things could be improved in dealing with complex partial differential equations. With these limitations, variations of these methods emerged and sought to deal with complex systems. The present thesis proposal involves the development of a numerical method that combines the Eulerian-Lagrangian Method (ELM) with the Method of Fundamental Solutions (MFS) to solve a series of examples modeled by the transport equation. In addition, Bayesian inference methodologies, such as particle filters, which allow the estimation of states and model parameters, will be considered, providing an inverse approach to the problem. The results contemplated the solution of benchmark cases, which have an analytical solution for evaluating the proposed method, showing accurate and stable results when tested against different Peclet numbers between 0.5-200. The method sensitivity to parameters, such as node number and positioning, was also investigated. Its performance was evaluated against metrics such as root mean squared error and absolute error. We also performed manipulations to original models to address the reaction term and extend the cases to high-dimensionalities and complex geometries using the proposed methodology.
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    Tribologia e Temperatura de Contato do Peek Deslizando Contra Latão, Peek e Alumina
    (Universidade Federal do Espírito Santo, 2024-01-30) Camporez, Rubson Mação; Scandian, Cherlio; https://orcid.org/0000-0002-4393-719X; http://lattes.cnpq.br/8466752738430250; https://orcid.org/0000-0003-2378-025X; http://lattes.cnpq.br/2417559348617413; Mello, Valdicleide Silva e; https://orcid.org/0000-0001-6413-6650; http://lattes.cnpq.br/4147387781308845; Strey, Nathan Fantecelle; https://orcid.org/0000-0002-2568-116X; http://lattes.cnpq.br/3613706957012460; Silva, Carlos Henrique da; https://orcid.org/0000-0002-2897-4347; http://lattes.cnpq.br/6218847264452522; Souza, Roberto Martins de; https://orcid.org/0000-0002-7384-1914; http://lattes.cnpq.br/4586350967708284
    The increase in contact temperature resulting from friction during sliding between bodies influences tribological behavior, leading to changes in the microstructure and properties of materials. This thermal increase can induce softening and melting of the bodies, phenomena particularly impactful in polymers due to their low glass transition and melting temperatures. Therefore, studying and predicting the contact temperature for polymeric materials is of paramount importance to maximize their tribological application. The calculation of the contact temperature can be performed by numerical methods or through mathematical models developed for problems of lesser geometric complexity and boundary conditions. Despite the relevance and presence of methodologies for determining the contact temperature, this challenge persists in contexts involving polymeric pairs. The obstacle arises from simplifications and from not considering changes in material properties as a function of temperature. A case that occurs with polymers is the alteration of thermal conductivity, which is sensitive to the molecular ordering of polymer chains, as well as to temperature and contact pressure. The literature has gaps to be filled regarding the contact temperature of polymers, especially polymer-polymer pairs. In this context, an investigation of the contact temperature of spheres and cylindrical pins (geometry) of two different diameters (dimension) of polyetheretherketone (PEEK), an ultra-high-performance polymer, sliding against brass, PEEK, and alumina discs was conducted, varying the normal load (13 different loads) and sliding velocity (0.5 and 1 m/s). Additionally, the surface temperature of the disc was measured during the test using an infrared thermal camera. Overall, it was observed that sliding velocity, geometry, dimension, and nature of the discs influenced the parameters used in calculating the contact temperature, such as heat partition and the Peclet number. In contrast, regarding the increase in flash temperature, nominal temperature, and maximum contact temperature, sliding velocity did not influence, while the geometry, dimension, and nature of the discs did. Errors between the temperature measured with the thermal camera and one of the components of the contact temperature were observed, and to improve the accuracy of the mathematical model, the use of correction factors called γ1 and γ2 was proposed, which multiply the thermal conductivities of the pin/sphere and disc, respectively. With their use, errors were reduced to zero under some conditions, increasing the applicability of the mathematical model of contact temperature.