Papers by Herbert M Gomes
Vehicle System Dynamics, 2015
The purpose of this paper is to determine the lumped suspension parameters that minimise a multio... more The purpose of this paper is to determine the lumped suspension parameters that minimise a multiobjective
function in a vehicle model under different standard PSD road profiles. This optimisation
tries to meet the rms vertical acceleration weighted limits for human sensitivity curves from ISO
2631 [ISO-2631: guide for evaluation of human exposure to whole-body vibration. Europe; 1997]
at the driver’s seat, the road holding capability and the suspension working space. The vehicle is
modelled in the frequency domain using eight degrees of freedom under a random road profile. The
particle swarm optimisation and sequential quadratic programming algorithms are used to obtain the
suspension optimal parameters in different road profile and vehicle velocity conditions. A sensitivity
analysis is performed using the obtained results and, in Class G road profile, the seat damping has
the major influence on the minimisation of the multi-objective function. The influence of vehicle
parameters in vibration attenuation is analysed and it is concluded that the front suspension stiffness
should be less stiff than the rear ones when the driver’s seat relative position is located forward the
centre of gravity of the car body. Graphs and tables for the behaviour of suspension parameters related
to road classes, used algorithms and velocities are presented to illustrate the results. In Class A road
profile it was possible to find optimal parameters within the boundaries of the design variables that
resulted in acceptable values for the comfort, road holding and suspension working space.
Proceedings of 10th World Congress on Computational Mechanics, 2014
Ingeniare. Revista chilena de ingeniería, 2016
Engineering Computations, 2005
Purpose – To research the feasibility in using artificial neural networks (ANN) and response surf... more Purpose – To research the feasibility in using artificial neural networks (ANN) and response surfaces (RS) techniques for reliability analysis of concrete structures. Design/methodology/approach – The evaluation of the failure probability and safety levels of structural systems is of extreme importance in structural design, mainly when the variables are eminently random. It is necessary to quantify and compare the importance
Brazilian Journal of Biomechanics Revista Brasileira De Biomecânica, Jun 25, 2013
Acta Scientiae Veterinariae, Jan 3, 2013
Background: Biological membranes demonstrate superiority over synthetic ones for its biocompatibi... more Background: Biological membranes demonstrate superiority over synthetic ones for its biocompatibility and strength in the reduction of abdominal hernias. Recents tissue engineering researches add mesenchymal stem cells to biological membranes with the purpose of obtaining additional cellular proliferation and consequent muscle regeneration, using biological membranes as cellular scaffolds. This article aimed to study the infl uence of mesenchymal stem cells in muscle regeneration in abdominal hernias, reduced with biological membranes.
Expert Systems With Applications an International Journal, 2011
In this paper, a structural truss mass optimization on size and shape is performed taking into ac... more In this paper, a structural truss mass optimization on size and shape is performed taking into account frequency constraints. It is well-known that structural optimizations on shape and size are highly non-linear dynamic optimization problems since this mass reduction conflicts with the frequency constraints especially when they are lower bounded. Besides, vibration modes may switch easily due to shape modifications.This paper intends to investigate the use of a particle swarm optimization (PSO) algorithm as an optimization engine in this type of problem. This choice is based on reported well-behavior of such algorithm as global optimizer in other areas of knowledge. Another feature of the algorithm is taken into account for this choice, like the fact that it is not gradient based, but just based on simple objective function evaluation. The algorithm is briefly revised highlighting its most important features.It is presented four examples regarding the optimization of trusses on shape and size with frequency constraints. The examples are widely reported and used in the related literature as benchmarks. The results show that the algorithm performed similar to other methods and even better in some cases.
Eng Computations, 2002
In this paper, special emphasis is given to uncertainties in the evaluation of the structural beh... more In this paper, special emphasis is given to uncertainties in the evaluation of the structural behavior, looking for a better representation of the system characteristics and quantification of the significance of these uncertainties in structural design. The reliability analysis of reinforced concrete structures is performed taking into account the spatial variability of material properties. The finite element method is used
International Journal of Vehicle Noise and Vibration, 2015
Proceedings of the 23rd ABCM International Congress of Mechanical Engineering, 2015
Proceedings of the 23rd ABCM International Congress of Mechanical Engineering, 2015
International Journal of Advanced Manufacturing Technology, 2013
In this study, we present a methodology for minimizing machining time, where the surface roughnes... more In this study, we present a methodology for minimizing machining time, where the surface roughness is constrained for the problem. The objective of the methodology is to encounter optimized cutting parameters which reduce machining time without reducing the surface quality of the machined workpiece. Three optimization schemes were considered to encounter the minima of a quantity which is a function of machining parameters: (a) sequential quadratic programming, (b) genetic algorithms, and (c) simulated annealing. For the discussion of the methodologies employed, an example of a machined surface is presented. The formalisms are used to obtain the parameters which minimize the machining time while maintaining the surface roughness within acceptable limits.
Resumo Atualmente os avanços em Redes Neurais Artificiais têm aberto novas perspectivas para a En... more Resumo Atualmente os avanços em Redes Neurais Artificiais têm aberto novas perspectivas para a Engenharia Estrutural. A robustez, adaptabilidade e capacidade de tratar dados incompletos e com ruídos tornam a Rede Neural uma alternativa para problemas deste tipo. Associado a análise da resposta dinâmica, esta técnica tem mostrado um comportamento robusto. A detecção do dano estrutural e identificação de elementos danificados em estruturas grandes e complexas é uma tarefa difícil. Já é bem conhecido que através de medidas de variações das freqüências naturais de estruturas e um bom modelo calibrado é possível detectar, tanto em posição quanto em intensidade, cenários de dano. Novos avanços têm sido feitos nesta área por meio de Redes neurais artificiais. Alguns problemas ainda existem com esta abordagem com respeito à identificação de locais danificados em estruturas simétricas. Este trabalho trata de alguns conceitos e princípios para a utilização de Redes Neurais Artificiais para a avaliação do dano. É feita uma breve revisão da literatura na aplicação de Redes Neurais para Detecção de Dano na última década. Algumas interessantes aplicações da técnica são relatadas. Ênfase é dada à aplicação de Redes Neurais com Funções de Base Radial. Um exemplo numérico é mostrado salientado-se as principais características do uso de redes neurais para a detecção e avaliação de dano. Neste exemplo em particular, o uso da Rede Neural se mostrou bastante promissor indicando um grande potencial para utilização em detecção de dano.
Proceedings of the Ninth International Conference on the Application of Artificial Intelligence to Civil, Structural and Environmental Engineering, 2007
Revista Internacional de Métodos Numéricos para Cálculo y Diseño en Ingeniería, 2014
Latin American Journal of Solids and Structures, 2012
This paper provides some information and numerical tests that aims to investigate the use of a Fu... more This paper provides some information and numerical tests that aims to investigate the use of a Fuzzy Controller applied to control systems. Some advantages are reported regarding the use of this controller, such as the characteristic ease of implementation due to its semantic feature in the statement of the control rules. On the other hand, it is also hypothesized that these systems have a lower performance loss when the system to be controlled is nonlinear or has time varying parameters. Numerical tests are performed using modal LQR optimal control and Fuzzy control of non-collocated systems with full state feedback in a twodimensional structure. The paper proposes a way of designing a controller that may be a supervisory Fuzzy controller for a traditional controller or even a fuzzy controller independent from the traditional control, consisting on individual mode controllers. Some comments are drawn regarding the performance of these proposals in a number of arrangements.
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Papers by Herbert M Gomes
function in a vehicle model under different standard PSD road profiles. This optimisation
tries to meet the rms vertical acceleration weighted limits for human sensitivity curves from ISO
2631 [ISO-2631: guide for evaluation of human exposure to whole-body vibration. Europe; 1997]
at the driver’s seat, the road holding capability and the suspension working space. The vehicle is
modelled in the frequency domain using eight degrees of freedom under a random road profile. The
particle swarm optimisation and sequential quadratic programming algorithms are used to obtain the
suspension optimal parameters in different road profile and vehicle velocity conditions. A sensitivity
analysis is performed using the obtained results and, in Class G road profile, the seat damping has
the major influence on the minimisation of the multi-objective function. The influence of vehicle
parameters in vibration attenuation is analysed and it is concluded that the front suspension stiffness
should be less stiff than the rear ones when the driver’s seat relative position is located forward the
centre of gravity of the car body. Graphs and tables for the behaviour of suspension parameters related
to road classes, used algorithms and velocities are presented to illustrate the results. In Class A road
profile it was possible to find optimal parameters within the boundaries of the design variables that
resulted in acceptable values for the comfort, road holding and suspension working space.
function in a vehicle model under different standard PSD road profiles. This optimisation
tries to meet the rms vertical acceleration weighted limits for human sensitivity curves from ISO
2631 [ISO-2631: guide for evaluation of human exposure to whole-body vibration. Europe; 1997]
at the driver’s seat, the road holding capability and the suspension working space. The vehicle is
modelled in the frequency domain using eight degrees of freedom under a random road profile. The
particle swarm optimisation and sequential quadratic programming algorithms are used to obtain the
suspension optimal parameters in different road profile and vehicle velocity conditions. A sensitivity
analysis is performed using the obtained results and, in Class G road profile, the seat damping has
the major influence on the minimisation of the multi-objective function. The influence of vehicle
parameters in vibration attenuation is analysed and it is concluded that the front suspension stiffness
should be less stiff than the rear ones when the driver’s seat relative position is located forward the
centre of gravity of the car body. Graphs and tables for the behaviour of suspension parameters related
to road classes, used algorithms and velocities are presented to illustrate the results. In Class A road
profile it was possible to find optimal parameters within the boundaries of the design variables that
resulted in acceptable values for the comfort, road holding and suspension working space.