Programa de Pós-Graduação em Modelagem e Otimização - PPGMO

URI Permanente desta comunidade

https://repositorio.ufcat.edu.br/handle/tede/26

O Mestrado em Modelagem e Otimização tem um papel essencial no desenvolvimento de novas tecnologias. Atualmente, se faz muito intensamente o uso de modelos matemáticos, simulações avançadas e sofisticados desenvolvimentos computacionais na pesquisa científica em geral. O objetivo do PPGMO é formar profissionais capazes de atuar no desenvolvimento da pesquisa na área de modelagem e otimização, para tratamento de modelos matemáticos e computacionais. Além de proporcionar ao aluno graduado em ciências exatas o aprofundamento do saber na área, que lhe permita alcançar padrão de competência científica ou técnico-profissional e oferecer, dentro da Universidade, ambiente e recursos adequados ao desenvolvimento da investigação científica.

Navegar

Agora exibindo 1 - 20 de 48

Modelo matemático para a definição de embalagens industriais: estudo de caso em uma empresa automobilística
(Universidade Federal de Goiás, 2016-02-15) Almeida, Tiago dos Santos; Queiroz , Thiago Alves de; http://lattes.cnpq.br/8041183668335400; Fuchigami, Hélio Yochihiro; http://lattes.cnpq.br/3025165325162182; Fuchigami, Hélio Yochihiro; http://lattes.cnpq.br/3025165325162182; Queiroz, Thiago Alves de; Santee, Donald Mark; Espinosa, José Waldo Martinez; Silva, Sérgio Francisco da
The procedure for determining the use of industrial packaging to a particular item is becoming more common in companies seeking to suit the conditions and needs of the costumer market, i.e., products that are marketed must from time to time be updated and / or replaced by new concepts. In the automotive industry, the launch of new vehicles has, in general, updated at least once a year, that is, for those responsible in determining the type of packaging to be used in the logistics flow there is always the need to analyze, define and implement new concepts in packaging. The objective of this paper is to propose a mathematical model that allows one to define the type of packaging to be used, considering the specifications of the part, assembly, and all its movement along the supply chain, minimizing the internal handling cost. The rationale for this work is linked to the constant need for packaging process definition, caused by the upgrading of products and process optimization. The difficulty is encountered when the process increases due to design of greater complexity with a high number of pieces and it influences the supply and assembly. This paper aims to conduct applied research, to study a practical problem and provide relevant expertise. Thus, the approach of quantitative research is due to the fact that it uses information that can be translated into numbers, in order to analyze and make the right conclusions. Thus, the research is exploratory as it involves a literature review on the theme, seeking authors that made related or similar studies. The mathematical model developed in this study was implemented in a vehicle assembler, and it was possible to verify the 50.27% reductions on internal handling costs given the solutions proposed by the integer programming model.
Efeitos do atraso sobre a estabilidade de sistemas mecânicos não lineares
(Universidade Federal de Goiás, 2016-03-04) Ferreira, Rosane Gonçalves; Rabelo, Marcos Napoleão; http://lattes.cnpq.br/0067281135180613; Rabelo, Marcos Napoleão; http://lattes.cnpq.br/0067281135180613; Santee, Donald Mark; Henrique, Marcos Luiz
Vibrations of mechanical systems have a wide field of research, where many work have been dedicated. Such importance is due to the fact that most human activities involve vibrations. It is worth noting that many device can suffer or produce vibrations, such as, machines, structures, motors, turbines. Vibratory systems, generally can produce complex behavior, thus the analysis of such dynamics behavior needs to use sophisticated mathematical tools. The mathematical model assigns important features of real processes with respect to linear and non-linear differential equations. In this work we are interested in the analysis of behavior of delayed mechanical systems. Time delayed can compromise the performance of controls even adding instability in the systems. On the other hand, write choose of delays can improve its performance. Systems with time delay, similar to ordinary systems, are molded by ordinary and/or partial differential equations, but, unlikely ordinary differential equations, delayed differential equations, also known as functional differential equations, are molded on Banach spaces with infinite dimension, which introduce serious difficulty in analysis of stability, since that, the spectra of solution semi-group associated with the linear part of the model can presents infinite eigenvalues. Thus, our contribution of the study of dynamics behavior of such systems will be in two directions. In the first one, we apply the perturbation method of multiple scales in themodel of differential equations, since that the system shows nonlinear vibrations. It is worth noting that the differential analysis used in the stage regarding differential equations in Banach spaces, which has infinite dimension, this approach differ substantially from standards approaches. Then we obtain numerical solutions for the amplitude at steady state using the Newton Raphson method and then we made a numerical analysis of the model of stability with delay and without delay to different parameters, using the Runge-Kuttamethod.
Técnica de redução de modelos improved reduced system enriched aplicada ao estudo do comportamento de sistemas mecânicos não lineares
(Universidade Federal de Goiás, 2016-03-08) Fonseca Júnior, Lázaro Antônio da; Lima, Antônio Marcos Gonçalves de; http://lattes.cnpq.br/0632660969306570; Borges, Romes Antonio; http://lattes.cnpq.br/3888145024042412; Borges, Romes Antonio; http://lattes.cnpq.br/3888145024042412; Steffen Junior, Valder; Stoppa, Marcelo Henrique
Currently, the structures are increasingly diverse and complex. In many cases, these structures are model by numerical approximations methods because, due to its complexity, the analytical model does not exist or is not feasible. The finite element method is a numerical approximation methods most used. Thus, the model generated by the finite element method is in most cases considerably too large, and the time taken to perform computer simulations is high. In this context, models reduction methods, it has been studied to meet the need of accurate results while maintaining the dynamic properties of the structure with less processing time. A comparative study of three reduction methods will be presented, the Improved Reduced System (IRS) and the Iterative Improved Reduced System method (IIRS). The third reduction method, it is an enrichment of the IRS method proposed by the author, which provided great improvement in time savings during simulations. This method was called Improved Reduced System Enriched (IRSE). Such reduction methods were applied in non-linear systems with non-localized linear and geometric nonlinearity due to large displacements. Keywords: Finite element method, nonlinear modeling, not linearity located and geometric, reduced models.
Aplicação dos mecanismos de locomoção do tipo Jansen em cadeiras de rodas
(Universidade Federal de Goiás, 2016-03-09) Borges, José Salviano; Stoppa, Marcelo Henrique; http://lattes.cnpq.br/1532505326645535; Stoppa, Marcelo Henrique; http://lattes.cnpq.br/1532505326645535; Pituba, José Julio de Cerqueira; Moura Júnior, José dos Reis Vieira de
To enlarge the active participation of individuals with disabilities in society, some mechanisms have been developed, such as crustches and wheelchairs. Wheelchairs are widely used, either temporarily or even permanently, allowing greater mobility and independence of the individual. However, the same is subject to the physical limitations of the wheels, requiring regular and hard grouynd to ensure bettermobility. Thus, some studies have suggested repacing the wheels on the legs, since the same part of the evolutionary process allows many terrestrial animals and viable movement to the wheels. The mechanisms with legs given the name of mobile machines. Among the most famous mobile machines are developed by the dutch phisicist Theo Jansen, called by Strandbeest. This study evaluates the repacement of the wheels of wheelchairs, for legs, trying to extend its use in less regular land. Also shown is the pattern of locomotion strcture developed by Jansen and the development of the Jansen similar structure using multiobjective optimizationmethods in order to ensure a new optimum configuration, and obtain a prototype proposed to be coupled in a conventional wheelchair. During the work it is proposed the method of wighted sumwith Pareto, this method related to onedimensionalyzation objectives. It also presents a brief comparison with two other methods –Weihted Sumand Pareto Ordination.
Análise de estabilidade em sistemas mecânicos não lineares com vistas a atenuação de vibrações
(Universidade Federal de Goiás, 2016-03-09) Purcina, Alcione Borges; Borges, Romes Antonio; http://lattes.cnpq.br/3888145024042412; Borges, Romes Antonio; http://lattes.cnpq.br/3888145024042412; Lima, Antônio Marcos Gonçalves de; Abud, Celso Vieira
In the last years, there is a growing interest in the study of nonlinear phenomena that because with the modernization of the structures and employment of innovative and more flexible materials, the nonlinearities become more evident. In that sense, this work aims to study the behavior of a mechanical system with two degrees of freedom with non-linear characteristics in primary resonance. The structure consists of the main system connected to a secondary system to act as a Nonlinear Dynamic Vibration Absorber, which partially or fully absorbs the vibrational energy of the system. The numerical solutions of the problem are obtained using the Runge-Kutta methods of 4th order and approximate analytical solutions are obtained using the Multiple Scales Method, and then it turns out how close can be closer to the numerical solutions. Through the mentioned disturbance method, too, it is determined the answers for the ordinary differential equations of the first order, which describe the modulation amplitudes and phases. Thus, the solution in steady state and the stability are studied using the frequency response. Furthermore, the behavior of the main system and the absorber are investigated through numerical simulations, such as responses in the time domain, phase planes and Poincaré map; which show that the system displays periodic movements, quasi-periodic and chaotic.
Classificação de insetos em milho à granel por meio de análise de vídeos endoscópicos
(Universidade Federal de Goiás, 2016-03-10) Geus, André Reis de; Silva, Sérgio Francisco da; http://lattes.cnpq.br/9061098995683609; Silva, Sérgio Francisco da; http://lattes.cnpq.br/9061098995683609; Rabelo, Marcos Napoleão; Henrique, Marcos Luiz
Insects cause significant losses of stored grains in both quantity and quality. In the scenary, it is of paramount importance an early identification of insects in grains to take control measures. Instead of sampling and visual/laboratory analysis of grains, we propose to carry out the insects identification task automatically, using computational methods to perform endoscopic video analysis. The videos are recorded inside of grains warehouses by an endoscopic camera. As the classification process of moving objects in video rely heavily on precise segmentation of moving objets, we propose a new method of background subtraction and compared their results with the main methods of the literature according to a recent review. The main innovation of the background subtractionmethod rely on the binarization process that uses two thresholds: a global and a local threshold. The binarized results are combined by adding details of the object obtained by the local threshold in the result of the global threshold. Experimental results performed through visual analysis of the segmentation results and using a SVM classifier, suggest that the proposed segmentation method produces more accurate results than the state-of-art background subtraction methods.
Introdução aos métodos de redução de modelos adaptados a sistemas mecânicos com características não lineares
(Universidade Federal de Goiás, 2016-03-11) Gonçalves, Daniel Ferreira; Lima, Antônio Marcos Gonçalves de; http://lattes.cnpq.br/0632660969306570; Borges, Romes Antonio; http://lattes.cnpq.br/3888145024042412; Borges, Romes Antonio; http://lattes.cnpq.br/3888145024042412; Rade., Domingos Alves; Moura Júnior, José dos Reis V. de
Studies focused on modeling and mechanical system behavior prediction are relevant to the avoidance of excessive deflections and structural failures. Most of these systems are discretized by finite element models which are constituted by a large number of degrees of freedom, making it quite expensive computationally. In this context, the application of models reduction methods becomes particularly prominent because it provides a greater saving in time, keeping the solution quality. This work aims to study methods of reducing models applied to nonlinear dynamical systems. Among the methods aimed at reducing models, there is the Guyan method, Improved Reduction System (IRS), Iterative Improved Reduction System (IIRS) System Equivalent Reduction Expansion Process (SEREP), Component Mode Synthesis (CMS) and method of modal projection. In order to verify the efficiency of the models reduction methods when applied to nonlinear systems is presented in this paper a study where the system responses are analyzed by checking the computational cost and quality of the reduced solution of the problem for each of the mentioned methods.
Modelagem e desenvolvimento de dispositivo para reabilitação de dedos da mão
(Universidade Federal de Goiás, 2016-06-18) Oliveira, Bruno Rodrigues de; Stoppa, Marcelo Henrique; http://lattes.cnpq.br/1532505326645535; Stoppa, Marcelo Henrique; Lucchese, Roselma; Rabelo, Marcos Napoleão
In everyday applications, the use of hands is essential in performing many tasks. Several situations such as car acidents, labor or stroke, impair mobility and maneuverability of the hands, forcing the individual to seek rehabilitation methods. This study aims to model and develop a device for rehabilitation of the finger that allows performthemovements of flexion / extension, within the limits of each joint. Evaluating types of fingers rehabilitation devices, they are observed its peculiarities and its main advantages, culminating in proposing an efficient model. Thus, this research presents the development of a more affordable device that meets the needs of patients in order to recover their normal activities.
Aplicação de uma abordagem robusta no problema de localização de ambulâncias com estudo de caso na cidade de Catalão - Goiás
(Universidade Federal de Goiás, 2016-07-05) Marques, Raina Ribeiro; Queiroz, Thiago Alves de; http://lattes.cnpq.br/8041183668335400; Queiroz, Thiago Alves de; Camargo, Victor Claudio Bento de; Borges, Romes Antônio
The robust optimization techniques can be used in problems subject to uncertainty in order to obtain robust solutions, that is, solutions that are less sensitive to the problem variations. Problems such as the facility location, specifically, the location of ambulances, have uncertainty in your data. Thus, an integer linear programming model for allocation of ambulances and stations is investigated considering that the service time is an uncertainty parameter, since this parameter is influenced by the nature of the call, traffic, or distance traveled, for example. It is proposed a model considering the application of a robust approach that controls the amount of uncertainty parameters related with the service time. A case study with real data provided by the fire department of the city of Catalão, Goiás, is performed on the models and the results show that the number of ambulances is greater than the current need, as pointed by the model without uncertainty. However, the results on the robust model show that the real number of ambulances in the city is able to serve a limited amount of demand, so for a maximum variation of the demand, the number of available ambulances are not able to support it. The model had worked well for the first two scenarios among the three ones tested, in which for the last scenario the model was quite sensitive to changes on the uncertainty parameters.
Parametrização dimensional, por modelo de regressão, de próteses de mão para crianças, confeccionadas por manufatura aditiva
(Universidade Federal de Goiás, 2016-08-24) Maia, Bruno Alves; Stoppa, Marcelo Henrique; http://lattes.cnpq.br/1532505326645535; Stoppa, Marcelo Henrique; Vera, Ivânia; Paula, Heber Martins de
The use of artificial limbs provides great improvements in the quality of life of people who were born with malformation or have lost their upper limbs. However, the value of conventional prostheses is not accessible to the majority of the population. In order to change this reality, began to emerge projects using additive manufacturing. The use of such technology allows the manufacture of more accessible and customized prostheses. However, the adequacy of project design is still a problem, due to the lack of data on the size of the upper limbs, especially on children and adolescents. Based on this need, this work seeks to find a way to parameterize the hand dimensions, thus helping in the better dimensioning of the prostheses. Thus, this work looks for a variable that presents satisfactory correlation with the dimensions of the upper limb. After finding such a relationship, a table and a parametric model were created that can estimate the length of the hand from the height.
Avaliação numérica e computacional do efeito de incertezas inerentes a sistemas mecânicos
(Universidade Federal de Goiás, 2016-08-25) Costa, Tatiane Nunes da; Borges, Romes Antonio; http://lattes.cnpq.br/3888145024042412; Borges, Romes Antonio; Cavallini Junior, Aldemir Aparecido; Rabelo, Marcos Napoleão
Most of the time, modern problems of engineering are nonlinear and, may also be subject to certain types of uncertainty that can directly influence in the answers of a particular system. In this sense, the stochastic methods have been thoroughly studied in order to get the best settings for a given project. Out of the stochastic techniques, the Method of Monte Carlo stands out and, especially the Latin Hypercube Sampling (LHS) which is a simpler version of the same. For this type of modeling, the Stochastic Finite Elements Method (SFEM) is becoming more frequently used, given that, an important tool for the discretization of stochastic fields can be given by the Karhunèn-Loève (KL) expansion. In this work, the following three case studies will be used: A discrete system of 2 g.d.l., a continuous system of a coupled beam type both in linear and nonlinear springs and a rotor consisting of axis, bearings and disks. In this sense, the influence of uncertainties in the systems studied will be checked, using for this, the LHS, SFEM and the KL expansion. The stochastic study in question will be used in the construction of the great project for the rotor problem already presented.
Análise estrutural estática por elementos finitos de um chassi veicular tipo spaceframe
(Universidade Federal de Goiás, 2016-08-25) Pereira, Clezidan Núcio; Moura Júnior, José Reis Vieira de; http://lattes.cnpq.br/2479225716217997; Stoppa, Marcelo Henrique; Stoppa, Marcelo Henrique; Moura Júnior, José Reis Vieira de; Santee, Donald Mark; Espinosa, José Waldo Martínez
Regarded as the main subsystem of a vehicle, the chassis are the link between the other subsystems and must also support multiple static and dynamic loads with stiffness, reliability and security. In this line, this paper presents the development and analysis of a vehicle three-dimensional structure spaceframe type, due to the complexity of the structure were used computational tooling in order to simulate the behavior of statically tubular structure, with the main objective to certify the reliability of the developed project, ensuring safety to drivers. The structure, existing, was modeled in CAD through SOLIDWORKS software, and their simulations were performed using the finite element method via commercial software ANSYS®. The simulationmethodology had the precise definition of loads and displacement constraints to the model in order to make the most plausible model possible. Were then performed computational analysis of rollover and frontal impact in the model (80 km/h e 60 km/h). Through the simulations, it was possible analyze the displacements arising from the critical situations in which the vehicle was submitted are consistent with what is recommended by regulating rules and bibliographies, with this in view that the chassis developed empirically and computationally simulated showed satisfactory results as its reliability and safety, are not required increment bars or modifying the system geometry.
Otimização topológica de absorvedores dinâmicos de vibrações sujeito a vibração livre e forçada
(Universidade Federal de Goiás, 2016-08-29) Mesquita, Gustavo Henrique Jesus; Santee, Donald Mark; http://lattes.cnpq.br/1738906012880469; Guimarães, Tobias Anderson; Moura Junior, José dos Reis Vieira de
The aim of this work is to propose a methodology of application of the FEM and topology optimization technique as tools of analysis and optimal design of mechanical systems subject to natural and forced vibrations in order to reach the optimal geometry of a dynamic absorbing of vibrations. It presents the mathematical reasoning and develop a program in Matlab® that implements the topology optimization technique will be employed to generate the optimal material distribution ( layout ) continuous mechanical systems without external excitation and subject to harmonic forces with preset frequency.
Redes neurais artificiais aplicadas à segmentação de imagens
(Universidade Federal de Goiás, 2017-02-15) Albanez, Daniela de Oliveira; Batista, Marcos Aurélio; http://lattes.cnpq.br/3637940122788341; Batista, Marcos Aurélio; Barcelos, Célia Aparecida Zorzo; Silva, Sérgio Francisco da; Rabelo, Marcos Napoleão; Silva, Núbia Rosa da
Image segmentation is one of image processing that problems that deserve special interest of the scientific community, given its real utility and application in various areas as medicine, geography, engineering, mathematics and computing, just to name a few. Much of the recent interest in segmentation has been motivated by the availability of satellite images on the Earth’s surface, which can be transformed into concrete knowledge, aiming at land use monitoring and data mining. This work proposes a new segmentation method, using Arficial Intelligence techniques, more specifically Artificial Neural Networks (ANNs), and compare its results of segmentation of satellite images with the original method. The binarized results are compared with the ground truth for the validation of the proposed segmentation method. Experimental results, quantative analysis of segmentation results, indicating that the proposed segmentation method generates better results and a decaying of 36.60% in the total average computacional time when compared with the original method.
Estabilidade de Carga no Problema de Carregamento de Contêineres
(Universidade Federal de Goiás, 2017-02-22) Oliveira, Liliane de Azevedo; Queiroz, Thiago Alves de; http://lattes.cnpq.br/8041183668335400; Queiroz, Thiago Alves de; Abud, Celso Vieira; Miyazawa, Flávio Keidi
In this work we applied an algorithm based on the resolution of integer linear models for the problem of packing boxes into a single container considering the cargo stability constraint. The problem consists of arranging items (boxes) of different sizes inside a large object (container) to maximize the occupied container volume while respecting the imposed constraints. Four methods are investigated and compared due to vertical cargo stability, in which three of these methods are proposed in this work and based on the equilibrium of rigid bodies, and the other one is based on the factor of support of boxes bottom faces. In the case of the factor of support, a set of constraints can be inserted totally in the integer formulation, while in the other methods cutting planes are inserted during optimization of the formulation by a branch-and-cut algorithm. Computational tests on instances from the literature show that the usage of a factor of support underestimates the value of the optimal solution. The computational tests showed that the use of the factor of support may underestimate the solution, but its use with integer linear programming models has the advantage that feasible solutions are stable, while the other developed methods only verify stability and thus they depend of the integer linear program to return feasible solutions more quickly. By the way, the methods for the cargo stability developed here also overcame the factor of support for tests involving different types of mesh to pack into the container.
Aplicação de verificação formal em um sistema de segurança veicular
(Universidade Federal de Goiás, 2017-03-07) Silva, Nayara de Souza; Stoppa, Marcelo Henrique; http://lattes.cnpq.br/1532505326645535; Costa, Vaston Gonçalves da; http://lattes.cnpq.br/5192533875584788; Costa, Vaston Gonçalves da; http://lattes.cnpq.br/5192533875584788; Galdino, André Luiz; Rabelo, Marcos Napoleão
The process of developing computer systems takes into account many stages, in which some are more necessary than others, depending on the purpose of the application. The implementation stage is always necessary, indisputably. Sometimes the requirements analysis and testing phases are neglected. And, generally, the part of formal verification correctness is intended for few applications. The use of model checkers has been exploited in the task of validating a behavioral specification in its appropriate level of abstraction, notably specifications validation of critical systems, especially when they involve the preservation of human life, when the existence of errors entails huge financial loss or when deals with information security. Therefore, it proposes to apply formal verification techniques in the validation of the vehicular safety system Avoiding Doored System, considered as critical, in order to verify if the implemented system faithfully meets the requirements for it proposed. For that, it was used as a tool to verify its correctness the Specification and Verification System - PVS, detailing and documenting all the steps employed in the process of specification and formal verification. K
Estimativa de recursos minerais e otimização de cava aplicados a um estudo de caso de uma mina de calcário
(Universidade Federal de Goiás, 2017-03-08) Pereira, Paulo Elias Carneiro; Ribeiro, Carlos Cordeiro; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4765922P6; Rabelo, Marcos Napoleão; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4702141E9; Ribeiro , Carlos Cordeiro; Borges, . Romes Antônio; Guimarães, Ednaldo Carvalho
A mining enterprise is composed of a set of successive and interdependent phases between them, which may or may not culminate in the exploitation of the mineral assets. The project begins with a Mineral Exploration phase, whose objective is to discover and subsequently evaluate the deposit for the feasibility of its extraction. This process involves setting the shape, dimensions and grades, resulting in a model that will be used to determine the recoverable reserves, that is, the economically usable part of the mineral resource, which will base the decision on the implementation or not of the enterprise, based mainly on technicaleconomic criteria. The elaboration of the physical form of the geological bodies that control the mineralization (geological model) and the estimation of the geological variables that characterize the quality of the different materials can be done by two approaches: by traditional or by geostatistical methods. The latter approach is currently being preferred, as it is a more accurate alternative and therefore, more reliable over traditional methods. The work uses indicator kriging (IK) and ordinary kriging (OK), both geostatistical tools, for the determination of the geological model and estimation of the geological variables (grades), respectively, of a limestone deposit located at Indiara city, Goiás State. Finally, from the obtained model the optimal limits of the extraction were established, based on the algorithm of Lerchs-Grossmann, that maximize the net present value of the enterprise. The results showed a significant deviation between themodel calculated by IK and the reality (samples), which can have as consequence the present spatial configuration of the sample data. The estimated geological variables also showed important deviations (overestimation and/or underestimation), particularly MgO oxide. The areas of occurrence of such deviations were coincident for all variables, which makes evident the existence of problems with the current sampling grid (spacing between samples and presence of very different sample supports), in such a way that it is recommended to collect additional samples, particularly with standardized supports. The optimal pit delimited a total reserve of 109,436,160.43 tons, with a total strip ratio of 0.13, which makes the venture, at first, attractive. This configuration, however, tends to be modified according to the collection of new geological evidence.
Projeto ótimo de um sistema automotivo utilizando materiais viscoelásticos
(Universidade Federal de Goiás, 2017-03-10) Andrade, Guilherme de Oliveira; Borges, Romes Antonio; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4737737P7; Diniz, Alberto Carlos Guimarães Castro; Rabelo, Marcos Napoleão; Borges, Romes Antonio
In order to attenuate unwanted vibrations, coming from mechanical systems, are increasing research in developing efficient products in the vibrant energy dissipation, being carried out in this line, full characterization of viscoelastic materials for the identification of its main phenomena and effectiveness check, reliability and security. The non-linear behavior of viscoelastic materials, when subjected to cyclic loading, is due to their microstructural characteristics, where it is possible that an effective vibration attenuation occurs. However, the complexity of the proposed problem suggests the implementation of numerical-computational procedures, the So that the deformation rates can be evaluated through harmonic analysis, so that the temperature variations can be defined and the phenomena associated with the material can be analyzed. With this, based on the dissipative characteristics of the material, the present work aims at the application of the same in the automotive area, being applied on the vehicular structure of utility vehicles aiming at the attenuation of the vibrations that arrive to the passenger compartment. To prove the efficacy of the material, the structural modeling of the viscoelastic was carried out in a computer environment (MatLab®) and then the material was inserted into the vehicle structure in the finite element software (Ansys®), where the structural and modal harmonic analysis , Thus verifying attenuations of the order of 8.746% for the second vibrating mode of the structure. However, due to the safety involved in automotive projects, it was necessary to analyze the computational effectiveness of these materials on the wide range of operational and environmental factors in which utility vehicles are submitted, thus guaranteeing the necessary reliability to the project.
Estudo de vibrações induzidas por linhas férreas
(Universidade Federal de Goiás, 2017-03-13) Silva, Gabriel Gomes; Borges, Romes Antônio; http://lattes.cnpq.br/3888145024042412; Borges, Romes Antonio; Silva, Alice Rosa da; Silva, Wellington Andrade da
Vibrations in the soil, induced by the passage of trains on railways, can cause countless effects in the areas bordering the railroads. In most problems, resort to simplified models of the system of interaction between rails foundation and trains for predicting responses that meet certain expectations, especially in order to avoid damaging nearby structures and also avoid discomfort of the people residing in areas surrounding the railway lines. Several soil-foundation interaction models have been developed seeking to get the answer to a foundation when subjected to static and dynamic actions, however, this response depends on multiple factors such as the nature and the mechanical characteristics of the terrain, the geometry of the elements involved, the rigidity of the foundation and the nature of his own excitement. Also of great importance in this type of analysis is the use of optimization techniques in order to obtain projects that are more realistic and safe from an engineering point of view. In this paper, was proposed a study of the effect of vibrations on railway lines, where it aims to model a system coupled between foundations and rails, subject to dynamic actions, in order to simulate the displacement in the time domain and in the domain of the frequency, using optimization for the construction of an optimum design that can attenuate the amplitudes of vibration of the system.
Sistema de controle ativo inibidor de lesões por pressão
(Universidade Federal de Goiás, 2017-03-28) Faria, Rafael Mendes; Stoppa, Marcelo Henrique; http://lattes.cnpq.br/1532505326645535; Stoppa, Marcelo Henrique; Paula, Heber Martins de; Vera, Ivânia
At the treatment sites of people who are bedridden, usually in Intensive Care Units, Long-Term Care Facilities for the Elderly and in the home environment due to the diffusion of home care, the incidence of Pressure Injury (LPP) is common. In order to reduce suffering and increase the life expectancy of patients with this problem, alternative methods are needed that can be introduced into the care of nursing teams to achieve the eradication or minimization of LPP. This paper presents a proposal of an innovative and low cost solution for LPP prevention. Applying concepts of automation and control, through existing technologies and low-cost components, the development of a device is developed that aims to assist the medical team and all those who have the responsibility of caring for individuals bedridden in LPP care. The device consists of pressure, humidity and temperature sensors, with a consequent real-time performance on these three variables at points with a higher probability of involvement of LPP.

Navegar

Navegando Programa de Pós-Graduação em Modelagem e Otimização - PPGMO por Data de Publicação

Resultados por página

Opções de Ordenação