Publicações - engenharias
|
Sander Joner;
Neida Maria Patias Volpi
Holos (Natal. Online),
v. 2,
n. 29,
p. 3-18,
2013
Palavra-chave:
Largura de banda;
sincronização;
Programação linear inteira mista
resumo ...
|
|
VIANNA JUNIOR, J. C.;
PAULA, J. C.;
Gideon Villar Leandro;
BONFIM, M. C.
Palavra-chave:
UAV;
Quad-rotor
Áreas do conhecimento:
Engenharias; Engenharia Elétrica; Telecomunicações
resumo ...
(en)
This paper describes the stages of identification, dynamic modelling and control of an unmanned aerial vehicle of type quad-rotor designed to capture images and video in high definition with relatively low cost. The identification process describes the methods used to identify the elements of the vehicle such as propellers parameters, mathematical modeling of the whole ESC-Motor-Propeller and modeling of the complete structure of the quad-rotor. PID controllers were used for the control and stabilization of the structure, controlling the rotational speed of the four motors independently. To tune the controller we have used the pole placement method, followed by simulations in MATLAB, based on the models obtained in identification. The simulations were validated with experimental measurements in prototype quad-rotor, leading to satisfactory results.
|
|
VIANNA JUNIOR, J. C.;
PAULA, J. C.;
LEANDRO, G. V.;
BONFIM, MARLIO
Palavra-chave:
Instrumentação Eletrônica;
VANT's;
controle e estabilidade
Áreas do conhecimento:
Engenharias; Engenharia Elétrica; Telecomunicações
resumo ...
(en)
This paper describes the stages of identification, dynamic modelling and control of an unmanned aerial vehicle of type quad-rotor designed to capture images and video in high definition with relatively low cost. The identification process describes the methods used to identify the elements of the vehicle such as propellers parameters, mathematical modeling of the whole ESC-Motor-Propeller and modeling of the complete structure of the quad-rotor. PID controllers were used for the control and stabilization of the structure, controlling the rotational speed of the four motors independently. To tune the controller we have used the pole placement method, followed by simulations in MATLAB, based on the models obtained in identification. The simulations were validated with experimental measurements in prototype quad-rotor, leading to satisfactory results.
|
|
Marienne do Rocio de Mello Maron da Costa;
Eduardo Pereira;
Rafael Giuliano Pileggi;
Maria Alba Cincotto
Palavra-chave:
argamassa colante;
propriedades;
Squeeze flow
Áreas do conhecimento:
Engenharias; Engenharia Civil; Construção Civil; Materiais e Componentes de Construção
resumo ...
(en)
A reologia estuda a deformação e o escoamento da matéria buscando descrever as deformações dos materiais dependentes do tempo, quando os mesmos são expostos a ações mecânicas. O presente trabalho propõe o entendimento do comportamento no estado fresco de argamassas colantes, com base na caracterização reológica de diferentes composições comerciais, a partir do ensaio “Squeeze Flow”, estabelecido na NBR 15839: 2010. Neste ensaio, o escoamento do material decorre da aplicação de uma carga de compressão sobre a amostra no estado fresco, a qual ocasiona deslocamentos no seu interior, devido a esforços de cisalhamento radiais originados durante o fluxo. Foi realizada ainda a caracterização física das argamassas e a viscosidade das pastas, com o objetivo de embasar a análise dos resultados obtidos com o Squeeze Flow. Observou-se que as argamassas estudadas apresentam diferenças de comportamento reológico, decorrente provavelmente, de ação sinérgica de alguns parâmetros da composição, com destaque para a distribuição granulométrica.
(pt)
Rheology studies the flow of matter seeking to describe the deformation of materials depending on the time they are exposed to mechanical actions. This paper proposes an understanding of the behavior of fresh adhesive mortar, from the Squeeze flow test. In this test, the flow of material results from the application of a compressive load on the fresh sample. It was further performed the physical characterization of mortars and viscosity of the pastes. It was observed that the mortars studied showed differences in rheological behavior, probably due to synergistic action of parameters of the composition, especially the particle size distribution.
|
|
João Almir Soares;
Manolo Lutero Gipiela;
Sérgio Fernando Lajarin;
Paulo Victor Prestes Marcondes
International Journal of Advanced Manufacturing Technology (Internet),
v. 65,
n. 1-4,
p. 451-457,
2013
DOI
Palavra-chave:
Punching of thick sheets;
clearance;
finite element;
Ductile damage
resumo ...
Sheet metal punching is an important industrial process for forming mechanical parts. Aimed at generating holes on thick sheets, punching process has been considered as a promising solution for the heavy industrial sector. The correct punching parameters choice has a direct influence on the hole quality. Since there exists rarely an analytical expression describing the relationships between these process parameters, the forming variable choice follows a series of costly try-and-error procedures on the workshop floor. The numerical simulation is a powerful tool that helps the forming engineers at the try-and-error procedures. This work shows the possibility of using FE-simulations to reduce the number of experiments that has to be conducted propitiating an increased understanding concerning some punching process parameters influence. The aim is the study of the clearance influence on the punched holes quality, 8 mm LNE38 sheet metal. Clearances of 0.2% up to 15% between the punch and die were analyzed. The influence of the punch–die clearance on the crack propagation was also analyzed, and the results were in agreement with the literature, i.e., good results for gaps within the traditional ideal range and occurrence of burr for clearance of 15%.
|
|
Paulo Victor Prestes Marcondes;
João Almir Soares;
Manolo Lutero Gipiela;
Sérgio Fernando Lajarin
International Journal of Advanced Manufacturing Technology (Internet),
v. 65,
n. 1-4,
p. 451-457,
2013
DOI
Palavra-chave:
Punching of thick sheets;
clearance;
finite element;
Ductile damage
resumo ...
Sheet metal punching is an important industrial process for forming mechanical parts. Aimed at generating holes on thick sheets, punching process has been considered as a promising solution for the heavy industrial sector. The correct punching parameters choice has a direct influence on the hole quality. Since there exists rarely an analytical expression describing the relationships between these process parameters, the forming variable choice follows a series of costly try-and-error procedures on the workshop floor. The numerical simulation is a powerful tool that helps the forming engineers at the try-and-error procedures. This work shows the possibility of using FE-simulations to reduce the number of experiments that has to be conducted propitiating an increased understanding concerning some punching process parameters influence. The aim is the study of the clearance influence on the punched holes quality, 8 mm LNE38 sheet metal. Clearances of 0.2% up to 15% between the punch and die were analyzed. The influence of the punch–die clearance on the crack propagation was also analyzed, and the results were in agreement with the literature, i.e., good results for gaps within the traditional ideal range and occurrence of burr for clearance of 15%.
|
|
BORCZ, C.;
Carlos Maurício Lepienski;
Silvio Francisco Brunatto
Palavra-chave:
niobio;
Nanodureza;
nitretação a plasma
resumo ...
|
|
Cláudio Borcz;
Carlos Maurício Lepienski;
Silvio Francisco Brunatto
Palavra-chave:
niobium;
Plasma Nitriding
resumo ...
|
|
BURTOLOSO, ANTONIO;
BERTONHA, ARIANE;
Isac George Rosset
Palavra-chave:
Fenantroindolizidines;
Organic Synthesis;
Biological activity
Áreas do conhecimento:
Ciências Exatas e da Terra; Química Orgânica; Síntese Orgânica;
Engenharias; Engenharia Química; Tecnologia Química; Produtos Naturais
resumo ...
Phenanthroindolizidine alkaloids are a well-known class of compounds due to their interesting biological activities,
especially anticancer ones. Represente...
|
|
ORDONEZ, J.C.;
Souza, Jeferson A.;
SHAH, DARSHIT R.;
Jóse Viriato Coelho Vargas;
Rob Hovsapian
Palavra-chave:
superconductors;
HTS DC cable;
mathematical model
resumo ...
The need to transfer large amounts of power in applications where cabling weight and space are a major issue has increased the interest in superconducting cables. Gaseous helium and neon are being considered as possible coolants due to their suitability for the expected operating temperature ranges. Gaseous helium is preferred due to its higher thermal conductivity and relatively lower cost than neon. This paper enhances a previously presented mathematical model of a superconducting cable contained in a flexible cryostat by including flow pressure drops. In this way, the model is capable of properly sizing and minimizing fan power, and allows the prediction of system response to localized heating events (e.g., quenching). A volume element model approach was used to develop a physics model, based on fundamental correlations, and principles of classical thermodynamics, mass and heat transfer, which resulted in a system of ordinary differential equations with time as the independent variable. The spatial dependence of the model is accounted for through the three-dimensional distribution of the volume elements in the computational domain. The model numerically obtains the temperature distribution under different environmental conditions. Pressure drop calculations are based on realistic correlations that account for the wavy nature of the coolant channels. Converged solutions were obtained within the imposed numerical accuracy even with coarse meshes.
|
