Leonardo Tavares Stutz
Rio de Janeiro State University
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Publication
Featured researches published by Leonardo Tavares Stutz.
Shock and Vibration | 2012
R.A. Tenenbaum; K.M. Fernandes; Leonardo Tavares Stutz; A.J. Silva Neto
The formulation and solution of the inverse problem of damage identification based on wave propagation approach are presented. Different damage scenarios for a bar are considered. Time history responses, obtained from pulse-echo synthetic experiments, are used toidentify damage position, severity and shape. In order to account for noise corrupted data, different levels of signal to noise ratio - varying from 30 to 0 dB - are introduced. In the identification process, different optimization methods are investigated: the deterministic Levenberg-Marquardt; the stochastic Particle Swarm Optimization; and a hybrid technique combining the aforementioned methods. It is shown that the damage identification procedure built on the wave propagation approach was successful, even for highly corrupted noisy data. Test case results are presented and a few comments on the advantages of deterministic and stochastic methods and their combination are also reported. Finally, an experimental validation of the sequential algebraic algorithm, used for modeling the direct problem, is presented.
Journal of The Brazilian Society of Mechanical Sciences and Engineering | 2011
Leonardo Tavares Stutz; Fernando A. Rochinha
The synthesis of a magneto-rheological vehicle suspension system built on the variable structure control approach is considered in the present work. The suspension is synthesized in order to improve the ride comfort obtained by a standard passive suspension. Although a nominal half-vehicle model with rigid body is considered in the synthesis of the suspension, phenomenological models for the MR dampers and for the seat-driver subsystem, along with the flexibility of the vehicle body, are considered in the performance assessment. For comparison purposes, active and magneto-rheological suspensions built on the optimal control approach and an active suspension built on the variable structure control approach are also considered. The numerical results show that the proposed suspension outperforms the passive suspension and presents a performance comparable to that of the active ones when the vehicle body may be assumed as rigid. Besides, when its flexibility is an important issue, a great performance drop may be observed, depending on the road quality, the damper characteristics and the adopted control strategy.
Shock and Vibration | 2013
Roberto A. Tenenbaum; Leonardo Tavares Stutz; K.M. Fernandes
The formulation and solution of the inverse problem of damage identification based on an one-dimensional wave propagation approach are presented in this paper. Time history responses, obtained from pulse-echo synthetic experiments, are used to damage identification. The identification process is built on the minimization of the squared residue between the synthetic experimental echo, obtained by using a sequential algebraic algorithm, and the corresponding analytical one. Fivedifferent hybrid optimization methods areinvestigated. The hybridization is performed combining the deterministic Levenberg-Marquardt method and each one of the following stochastic techniques: The Particle Swarm Optimization; the Luus-Jaakola optimization method; the Simulated Annealing method; the Particle Collision method; and a Genetic Algorithm. A performance comparison of the five hybrid techniques is presented. Different damage scenarios are considered and, in order to account for noise corrupted data, signals with 10 dB of signal to noise ratio are also considered. It is shown that the damage identification procedure built on the Sequential Algebraic Algorithm yielded to very fast and successful solutions. In the performance comparison, it is also shown that the hybrid technique combining the Luus-Jaakola and the Levenberg-Marquardt optimization methods provides the faster damage recovery.
Journal of Physics: Conference Series | 2008
Francisco J. C. P. Soeiro; Leonardo Tavares Stutz; R.A. Tenenbaum; A.J. Silva Neto
Magneto-rheological (MR) dampers are semi-active control devices that require low power input and are considered fail-safe, i.e. in case of control hardware failure they become passive dampers. In the present work we consider a sensitivity analysis and use the deterministic gradient based Levenberg-Marquardt method, the stochastic methods Simulated Arnealing and Genetic Algorithms, as well as hybridizations of these methods, for the estimation of parameters in the Bouc-Wen model, which is used to describe the dynamic behavior of MR dampers. The parameters associated with the histeretic displacement evolution equation are the most difficult to be estimated, and therefore we use a strategy for estimating such parameters separately from other parameters of the model.
Proceeding Series of the Brazilian Society of Computational and Applied Mathematics | 2018
Josiele da Silva Teixeira; Leonardo Tavares Stutz; Antônio José da Silva Neto
O presente trabalho tem como objetivo apresentar um estudo referente a aplicacao da abordagem Bayesiana como tecnica de solucao do problema de identificacao de danos estruturais. [...]
Proceeding Series of the Brazilian Society of Computational and Applied Mathematics | 2018
Isabela Cristina da Silveira e Silva Rangel; Diego Campos Knupp; Leonardo Tavares Stutz; Luciano dos Santos Rangel
O presente trabalho aborda o problema de identificacao de danos em vigas a partir de um Modelo de Superficie de Resposta (MSR) da matriz de flexibilidade estrutural . O dano e descrito por um parâmetro de coesao, discretizado espacialmente pelo Metodo dos Elementos Finitos (MEF). O problema inverso e formulado segundo a abordagem Bayesiana, de modo que a solucao do problema consiste na determinacao de densidades de probabilidade marginais a posteriori dos parâmetros nodais de coesao. O metodo de Monte Carlo com Cadeias de Markov (MCMC) foi utilizado para a obtencao das densidades de probabilidade. Diante dos resultados obtidos, pode-se concluir que a abordagem proposta foi capaz de identificar com acuracia os campos de dano considerados.
Proceeding Series of the Brazilian Society of Computational and Applied Mathematics | 2018
Luciano dos Santos Rangel; Carlos Eduardo Závoli Cordeiro; Gustavo Nogueira Lopes da Silva; Isabela Cristina da Silveira e Silva Rangel; Diego Campos Knupp; Leonardo Tavares Stutz
O presente trabalho aborda a identificacao de danos estruturais em uma viga de Euler-Bernoulli simplesmente apoiada. [...]
Proceeding Series of the Brazilian Society of Computational and Applied Mathematics | 2017
Isabela Cristina da Silveira e Silva Ran; Leonardo Tavares Stutz; Luciano dos Santos Rangel; Rosilene Abreu Corrêa
O presente trabalho aborda um problema de identificacao de danos estruturais baseado na analise modal, mais precisamente, na matriz de flexibilidade, em uma viga de Euler-Bernoulli simplesmente apoiada. O Modelo de Superficie de Resposta (MSR) e utilizado para a obtencao da matriz de flexibilidade em substituicao ao Modelo de Elementos Finitos (MEF) na formulacao do problema inverso da identificacao de danos e, para tal, e utilizado o metodo Evolucao Diferencial (ED). Frente aos resultados numericos obtidos, a estrategia adotada mostrou-se capaz de identificar os danos com elevada acuracia, mostrando assim, sua potencialidade.
Proceeding Series of the Brazilian Society of Computational and Applied Mathematics | 2017
Luciano dos Santos Rangel; Isabela Cristina da Silveira e Silva Ran; Leonardo Tavares Stutz
Neste trabalho, e utilizado o Projeto Otimo de Experimentos, sendo considerados os criterios D-otimo, Determinante do momento e G-eficiencia, para determinacao do experimento otimo, que se baseia em indicar o posicionamento otimo do sensor de deslocamento e a quantidade de dados experimentais a serem utilizados no processo de identificacao de danos. Diante dos resultados obtidos, observou-se que esse procedimento contribuiu para a identificacao de danos estruturais.
Proceeding Series of the Brazilian Society of Computational and Applied Mathematics | 2015
Cleber de Almeida Corrêa Junior; Rosilene Abreu Portella Corrêa; Isabela Cristina da Silveira e Silva Rangel; Luciano dos Santos Rangel; Leonardo Tavares Stutz
O presente trabalho propoe um novo metodo estocastico de otimizacao global denominado Alcateia, o qual e um metodo baseado no comportamento dos lobos. Suas principais caracteristicas e a necessidade de apenas um parâmetro de controle a ser calibrado e facil implementacao. Analises numericas considerando a identificacao de danos estruturais em uma estrutura do tipo viga de Euler-Bernoulli simplesmente apoiada utilizando os dados baseados no dominio da frequencia foi realizada, com intuito de verificar o desempenho do metodo proposto. Diante dos resultados apresentados, pode-se considerar que o metodo conseguiu localizar e quantificar corretamente os danos na estrutura, mesmo considerando ruido aditivo.
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Isabela Cristina da Silveira e Silva Rangel
Rio de Janeiro State University
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