Browsing by Author "Mapa, Lidianne de Paula Pinto"

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    Dynamic behavior of tapping axial force.
    (2021) Pereira, Igor Cezar; Mapa, Lidianne de Paula Pinto; Barros, Thamiris Nogueira de; Fortes, Reinaldo Clemente; Silva, Marcio Bacci da; Guimarães, Gustavo Paulinelli
    Background Tapping is one of the processes that most requires attention in the industry, due to the stage in which it occurs and its characteristics. In the case of tapping, it is common to use components and equipment with less rigidity, which com promises the dynamic behavior in several situations and can lead to process distortion or failure. Purpose The objective of this paper is to study the dynamic behavior of tapping in relation to several characteristics of the process. Methods The dynamic behavior of the force signal was used to evaluate the process, varying the cutting parameters and the clamping system of the workpiece. Results The experimental results indicate that the foating system did not present a good dynamic behavior at high cutting speeds, this greater application of vibration is due to the resonance due to the combination of oscillations under forced and natural vibration. Conclusions The natural frequency of the foating fxture system infuenced the behavior of the axial forces. The increase in cutting speed resulted in a direct increase in the axial force vibrations as its frequency came close to the natural frequency of the system. Through dynamic analysis of the axial force signal observed the dynamic characteristics of the process and the machine tool. This allowed the dynamic evaluation of the system through the measurement of force signals generated in the threading process.
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    Dynamic substructuring by the craig–bampton method applied to frames.
    (2020) Mapa, Lidianne de Paula Pinto; Neves, Francisco de Assis das; Guimarães, Gustavo Paulinelli
    Purpose The Craig–Bampton method is a substructuring technique that reduces the number of internal degrees of freedom of substructures by approximations, using a set of truncated vibration modes. It is useful for structural designs with many degrees of freedom. This work aims to develop substructuring through the Craig–Bampton method for free vibration analysis on planar frames according to the frequency range of interest. Methods The fnite-element models of diferent substructures were assembled. Thus, the degrees of physical freedom were reduced according to the frequency range of interest. The reduced-order models were coupled. Thus, the physical response was obtained. Detailed calculation and the algorithm fowchart are provided. Conclusions The study of frame dynamics using the present method in diferent frequency ranges of interest was presented and validated with the results of a commercial software. It was possible to clarify the coupling formulations of the component mode synthesis, as well as the amount of reduction of the number of equations provided by the method, reaching less than 4% of the complete model, for the considered cases.
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    Naturally ventilated industrial sheds : an investigation about the influence of wind direction in flow rate efficiency in continuous roof vents.
    (2021) Camargos, Bruno Henrique Lourenço; Souza, Henor Artur de; Gomes, Adriano Pinto; Ladeira, Artur Hallack; Reis, Reinaldo Antonio dos; Mapa, Lidianne de Paula Pinto
    Natural ventilation portrays an effective technique for lowering the internal temperature, without spending electricity, and directly contributes to the renewal of indoor air by establishing a healthy environment for workers. Given this, it is usual to have air vent openings located at the top of the roof (continuous roof vents), in addition to those present on the facades of sheds. In naturally ventilated buildings, it is recommended to give due importance to the provision of these openings, since depending on the proposed arrangement, the wind may or may not help in the effectiveness of this strategy. In this work, it is evaluated via computer simulation (EnergyPlus, version 8.7.0), for the climatic conditions of the city of Belo Horizonte/Brazil, the influence of the wind direction in the flow rate of indoor air through the ridge vents, of the longitudinal and transversal type, present in industrial sheds endowed with an internal source of high-intensity heat release. The results obtained show that the flow rate has a symmetrical behavior in the openings of the longitudinal continuous roof vent, that is, when an opening is with the maximum outflow of the internal air, the opening opposite the predominant wind direction is acting as an entry point for the air external. The transverse continuous roof vents are more sensitive about the wind direction since they are positioned perpendicular to the building. The best result found is for the wind situation occurring parallel to the shed, obtaining a reduction in the internal temperature of up to 1°C, an increase in the rate of air changes per hour, in the internal environment, at 1acph, and an increase of up to 10,7% in the volume of air infiltrated into the shed.
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    Numerical implementation for conception of strut and tie models in reinforced concrete structures.
    (2020) Ladeira, Artur Hallack; Silva, Amilton Rodrigues da; Camargos, Bruno Henrique Lourenço; Mapa, Lidianne de Paula Pinto; Reis, Reinaldo Antonio dos
    O Modelo de Bielas e Tirantes pode ser uma excelente alternativa para o dimensionamento de elementos estruturais em concreto armado submetidos a estado plano de tensão e para regiões que apresentem descontinuidade de ordem geométrica ou estática, substituindo procedimentos empíricos por uma metodologia racional de projeto. Para tornar a concepção do modelo menos dependente da experiência do projetista, o presente artigo tem como objetivo aliar a técnica de otimização topológica ESO (Evolutionary Structural Optimization) ao Método dos Elementos Finitos para geração automática dos modelos de bielas e tirantes. O critério de evolução do método de otimização topológica adotado considera a eliminação de elementos menos solicitados em termos de tensão, a partir de uma análise elástico-linear. Nesse contexto, é possível obter soluções otimizadas de problemas complexos envolvendo o concreto estrutural. São apresentados três exemplos numéricos para comprovação e validação das formulações e técnicas implementadas, cujos modelos de bielas e tirantes obtidos apresentam boa concordância em relação às respostas encontradas em trabalhos científicos precursores sobre o tema.
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    Study of the project parameters influence in the performance of solar collectors.
    (2019) Mapa, Lidianne de Paula Pinto; Mendes, Bárbara de Morais; Bortolaia, Luis Antônio; Leal, Elisângela Martins
    This paper aims to observe the influence of design parameters on the performance of plane solar collectors. From the energy balance of the plane solar collector, the mathematical model was implemented varying the following design parameters: (i) Thickness of the absorber plate; (ii) Distance between the absorber and the cover; (iii) Edge insulation thickness; (iv) Absorber emittance; (v) Conductivity of the absorber; (vi) Convective heat transfer coefficient inside the tubes; (vii) Distance between tubes; (viii) Wind velocity; (ix) Solar radiation incident; and (x) Back insulation thickness. These parameters were altered observing the influence on the optical efficiency; the coefficient of energy loss; the instantaneous efficiency; and the useful energy gain. From the results, it is possible to see that the parameters that most influence the performance of the solar collector are the distance between the absorber and the cover, the absorber emittance, the thermal conductivity of the absorber, the distance between tubes, wind speed and solar radiation incident.
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    Subestruturação dinâmica por meio do método de CRAIG-BAMPTON aplicada a pórticos planos.
    (2018) Mapa, Lidianne de Paula Pinto; Neves, Francisco de Assis das; Guimarães, Gustavo Paulinelli; Neves, Francisco de Assis das; Alves, Vinicius Nicchio; Guimarães, Gustavo Paulinelli
    O presente trabalho tem como objetivo desenvolver o algoritmo de subestruturação linear através do método de Craig-Bampton para elementos de pórtico. Nesse contexto, busca-se esclarecer as formulações de acoplamento da síntese modal de componentes, mais especificadamente do método de Craig-Bampton. O algoritmo implementado foi aplicado ao acoplamento de vigas e pórticos. Essas aplicações foram direcionadas para otimização de estruturas, ou seja, quando deseja-se alterar a estrutura a fim de obter as frequências e modos naturais desejados. A redução da ordem de modelos proporcionada pelo método é descrita em cada aplicação. Análises via Método de Elementos Finitos (MEF) implementado e também através do software SAP 2000 possibilitaram a validação do algoritmo implementado.