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.
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
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.
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
Proceedings of the Ninth International Conference on the Application of Artificial Intelligence to Civil, Structural and Environmental Engineering, 2007
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.
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
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.
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
Proceedings of the Ninth International Conference on the Application of Artificial Intelligence to Civil, Structural and Environmental Engineering, 2007
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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.