Browsing by Author "Silva, Tiago Alexandre Narciso da"
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- Análise dinâmica de um equipamento industrialPublication . Silva, Tiago Alexandre Narciso daEquipamentos rotativos podem ser encarados como vigas em apoios elásticos suportando um número finito de elementos concentrados ao longo do seu comprimento. Em operação, este tipo de equipamento pode ser exposto a solicitações dinâmicas severas. Com a finalidade de evitar regimes críticos, os autores propõem um algoritmo baseado no Quociente de Rayleigh, utilizando ateoria das vigas de Bernoulli-Euler. Este algoritmo permite a determinação das soluções próprias de vigas contínuas, considerando diversas condições de fronteira e o efeito da massa concentrada e inércia de rotação dos elementos suportados. Tentando reproduzir as configurações de sistemasreais são usadas diferentes condições de fronteira na formulação da teoria das vigas de Bernoulli- Euler. Salienta-se o facto dos dados analíticos serem experimentalmente verificados através de ensaios de impacto, sendo por sua vez utilizados como entradas do algoritmo de modelação, para a identificação da rigidez torsional dos apoios. Os resultados são discutidos e comparados,sempre que apropriado, com resultados já publicados. Finalmente, o trabalho futuro é delineado.
- A hybrid procedure to identify the optimal stiffness coefficients of elastically restrained beamsPublication . Silva, Tiago Alexandre Narciso da; Loja, Amélia; Maia, Nuno; Barbosa, JoaquimThe formulation of a bending vibration problem of an elastically restrained Bernoulli-Euler beam carrying a finite number of concentrated elements along its length is presented. In this study, the authors exploit the application of the differential evolution optimization technique to identify the torsional stiffness properties of the elastic supports of a Bernoulli-Euler beam. This hybrid strategy allows the determination of the natural frequencies and mode shapes of continuous beams, taking into account the effect of attached concentrated masses and rotational inertias, followed by a reconciliation step between the theoretical model results and the experimental ones. The proposed optimal identification of the elastic support parameters is computationally demanding if the exact eigenproblem solving is considered. Hence, the use of a Gaussian process regression as a meta-model is addressed. An experimental application is used in order to assess the accuracy of the estimated parameters throughout the comparison of the experimentally obtained natural frequency, from impact tests, and the correspondent computed eigenfrequency.
- Optimal location of supports in beam structures using genetic algorithmsPublication . Loureiro, Diógenes; Loja, Amélia; Silva, Tiago Alexandre Narciso daReal structures can be thought as an assembly of components, as for instances plates, shells and beams. This later type of component is very commonly found in structures like frames which can involve a significant degree of complexity or as a reinforcement element of plates or shells. To obtain the desired mechanical behavior of these components or to improve their operating conditions when rehabilitating structures, one of the eventual parameters to consider for that purpose, when possible, is the location of the supports. In the present work, a beam-type structure is considered, and for a set of cases concerning different number and types of supports, as well as different load cases, the authors optimize the location of the supports in order to obtain minimum values of the maximum transverse deflection. The optimization processes are carried out using genetic algorithms. The results obtained, clearly show a good performance of the approach proposed. © 2014 IEEE.
- A remote virtual experiment in mechanical engineeringPublication . Silva, Tiago Alexandre Narciso da; Loja, AméliaThe current paper presents an educational platform that is intended to promote and to develop students' motivation and competences both in the fields of mechanical design and structural optimization, by taking as demonstration the problem of minimizing thermal residual stresses in functionally graded structures, using the differential evolution optimization technique. These goals are enabled by taking advantage of the friendly interaction between two commercial software packages, MATLAB and LabVIEW, which can provide an integrated tool for engineering education and research. The educational platform empowers students to an easier perception and intermediate results tracking, concerning to the optimization process, as well as the influence, on thermal residual stresses, of considering different: temperature distribution profile, layer thickness or volume fraction law exponent, among other optimization related parameters. This pilot project is entering on its implementation phase, wherein students are required to explore the multiple potentialities of this platform to support their learning process.
- Unbalance and field balacing virtual labsPublication . Sampaio, Rui Pedro Chedas; Silva, Tiago Alexandre Narciso daOne of the most common problems of rotating machinery is the rotor unbalance. The effects of rotor unbalance can vary from the malfunction of certain equipment to diseases related to the exposure to high vibration levels. However, the balancing procedure is known, it is mandatory to have qualified technicians to perform it. In this sense, the use of virtual balancing experiments is of great interest. The present demo is dedicated to present two different balancing simulators, which can be explored in conjunction, as they have complementary outputs. © 2014 IEEE.