Vilson Pereira - Academia.edu (original) (raw)
Papers by Vilson Pereira
Proceedings of the 26th International Congress of Mechanical Engineering, 2021
Concilium, Mar 2, 2023
Sound field behavior in an acoustic enclosure is an important part of the design of transportatio... more Sound field behavior in an acoustic enclosure is an important part of the design of transportation vehicle passenger cabin, concert halls, conference rooms, and etc. Different analysis methods are available and have strengths and weaknesses. Low frequency band envelopes and negligible absorption in the walls can be modeled by Modal Analysis or Finite Element Method. However, as the frequency band increases, both methods become computationally intensive and Statistical Energy Analysis or the Sabine model can be an efficient approach. However, these methods do not take into account any spatial variation within the enclosure. The Energy Flow Analysis (EFA) solution for acoustic enclosures can be done analytically. In this paper, the Energy Spectral Element Method (ESEM) is formulated and applied to predict the spatial distribution of energy flux and density of acoustic ducts at high frequencies. ESEM is a matrix methodology based on EFA to solve acoustic and structural vibration problems. In this work, numerical models involving simple and coupled one-dimensional acoustic ducts are generated by ESEM, and the results are compared with energy densities calculated from the pressure fields predicted by the Spectral Element Method (SEM).
Computers & Structures, Apr 1, 2014
At mid-and high-frequency bands, displacement-based approaches such as the finite element method ... more At mid-and high-frequency bands, displacement-based approaches such as the finite element method (FEM) create too large models, while energy-based methods, such as statistical energy analysis, produce smaller ones, but without spatial variation. Energy flow analysis (EFA) can produce compact models that include spatial variation; however, their analytical solution makes them difficult to handle for built-up structures. To overcome this issue, the energy finite element method (EFEM), a finite element solution of EFA, was proposed. A more accurate alternative to EFEM is the energy spectral element method (ESEM). It is a matrix methodology applied to EFA similar in style to FEM, with one significant difference being the use of the analytical solution as interpolation functions. Simulated results obtained by EFEM and ESEM are analysed and compared with each other and with the spectral element method, which is used as a reference.
Concilium
Sound field behavior in an acoustic enclosure is an important part of the design of transportatio... more Sound field behavior in an acoustic enclosure is an important part of the design of transportation vehicle passenger cabin, concert halls, conference rooms, and etc. Different analysis methods are available and have strengths and weaknesses. Low frequency band envelopes and negligible absorption in the walls can be modeled by Modal Analysis or Finite Element Method. However, as the frequency band increases, both methods become computationally intensive and Statistical Energy Analysis or the Sabine model can be an efficient approach. However, these methods do not take into account any spatial variation within the enclosure. The Energy Flow Analysis (EFA) solution for acoustic enclosures can be done analytically. In this paper, the Energy Spectral Element Method (ESEM) is formulated and applied to predict the spatial distribution of energy flux and density of acoustic ducts at high frequencies. ESEM is a matrix methodology based on EFA to solve acoustic and structural vibration proble...
Proceedings of the XI Congresso Nacional de Engenharia Mecânica - CONEM 2022
Proceedings of the XI Congresso Nacional de Engenharia Mecânica - CONEM 2022
The consideration of uncertainties in numerical models to obtain the probabilistic descriptions o... more The consideration of uncertainties in numerical models to obtain the probabilistic descriptions of dynamic response is becoming more desirable in the way to quantify the parametric and non-parametric uncertainties associated with the model. In this work, an alternative approach to the spectral element formulation, in which the exact wave solutions are not required, the spectral element matrix including random parameters is derived from the transfer matrix formulated directly from the frequency-domain state-vector equation of motion. The analyses were made to quantify the effect of uncertainty in the dynamic responses at high frequency bands and the Monte Carlo simulation is used to propagate the variation in dimensional properties of the structural parameters. Some interesting results are presented, showing the effects of uncertainty parameters in the dynamic response of the structure
Proceedings of the 26th International Congress of Mechanical Engineering, 2021
Abstract. Sound field behaviour in an acoustic enclosure is an important part of the cabin passen... more Abstract. Sound field behaviour in an acoustic enclosure is an important part of the cabin passenger transport vehicle design, concert halls, conference rooms, etc., different analytical methods are available to design engineers, which has its strengths and weaknesses. Cavities in a low-frequency band and negligible absorption on the walls can be modelled by Modal Analysis and Finite Element Method. However, when the frequency band increases, both methods become computationally expensive and Statistical Energy Analysis or Sabine model can be an efficient approach. These methods assume deterministic treatment and almost nothing is known about the effect of uncertainties in the parameters, acoustic velocity and acoustic pressure inside cavities. This paper presents a study on the patterns of density and energy flow generated guide acoustic waves at high frequencies including uncertainties in geometric parameters and property of fluids. The waveguide is modelled by the Spectral Elemen...
As Engenharias frente a Sociedade, a Economia e o Meio Ambiente 5, 2020
Anais do X Congresso Nacional de Engenharia Mecânica, 2018
Anais do IX Congresso Nacional de Engenharia Mecânica, 2016
Proceedings of the Ninth International Conference on Computational Structures Technology
Proceedings of the 26th International Congress of Mechanical Engineering, 2021
Concilium, Mar 2, 2023
Sound field behavior in an acoustic enclosure is an important part of the design of transportatio... more Sound field behavior in an acoustic enclosure is an important part of the design of transportation vehicle passenger cabin, concert halls, conference rooms, and etc. Different analysis methods are available and have strengths and weaknesses. Low frequency band envelopes and negligible absorption in the walls can be modeled by Modal Analysis or Finite Element Method. However, as the frequency band increases, both methods become computationally intensive and Statistical Energy Analysis or the Sabine model can be an efficient approach. However, these methods do not take into account any spatial variation within the enclosure. The Energy Flow Analysis (EFA) solution for acoustic enclosures can be done analytically. In this paper, the Energy Spectral Element Method (ESEM) is formulated and applied to predict the spatial distribution of energy flux and density of acoustic ducts at high frequencies. ESEM is a matrix methodology based on EFA to solve acoustic and structural vibration problems. In this work, numerical models involving simple and coupled one-dimensional acoustic ducts are generated by ESEM, and the results are compared with energy densities calculated from the pressure fields predicted by the Spectral Element Method (SEM).
Computers & Structures, Apr 1, 2014
At mid-and high-frequency bands, displacement-based approaches such as the finite element method ... more At mid-and high-frequency bands, displacement-based approaches such as the finite element method (FEM) create too large models, while energy-based methods, such as statistical energy analysis, produce smaller ones, but without spatial variation. Energy flow analysis (EFA) can produce compact models that include spatial variation; however, their analytical solution makes them difficult to handle for built-up structures. To overcome this issue, the energy finite element method (EFEM), a finite element solution of EFA, was proposed. A more accurate alternative to EFEM is the energy spectral element method (ESEM). It is a matrix methodology applied to EFA similar in style to FEM, with one significant difference being the use of the analytical solution as interpolation functions. Simulated results obtained by EFEM and ESEM are analysed and compared with each other and with the spectral element method, which is used as a reference.
Concilium
Sound field behavior in an acoustic enclosure is an important part of the design of transportatio... more Sound field behavior in an acoustic enclosure is an important part of the design of transportation vehicle passenger cabin, concert halls, conference rooms, and etc. Different analysis methods are available and have strengths and weaknesses. Low frequency band envelopes and negligible absorption in the walls can be modeled by Modal Analysis or Finite Element Method. However, as the frequency band increases, both methods become computationally intensive and Statistical Energy Analysis or the Sabine model can be an efficient approach. However, these methods do not take into account any spatial variation within the enclosure. The Energy Flow Analysis (EFA) solution for acoustic enclosures can be done analytically. In this paper, the Energy Spectral Element Method (ESEM) is formulated and applied to predict the spatial distribution of energy flux and density of acoustic ducts at high frequencies. ESEM is a matrix methodology based on EFA to solve acoustic and structural vibration proble...
Proceedings of the XI Congresso Nacional de Engenharia Mecânica - CONEM 2022
Proceedings of the XI Congresso Nacional de Engenharia Mecânica - CONEM 2022
The consideration of uncertainties in numerical models to obtain the probabilistic descriptions o... more The consideration of uncertainties in numerical models to obtain the probabilistic descriptions of dynamic response is becoming more desirable in the way to quantify the parametric and non-parametric uncertainties associated with the model. In this work, an alternative approach to the spectral element formulation, in which the exact wave solutions are not required, the spectral element matrix including random parameters is derived from the transfer matrix formulated directly from the frequency-domain state-vector equation of motion. The analyses were made to quantify the effect of uncertainty in the dynamic responses at high frequency bands and the Monte Carlo simulation is used to propagate the variation in dimensional properties of the structural parameters. Some interesting results are presented, showing the effects of uncertainty parameters in the dynamic response of the structure
Proceedings of the 26th International Congress of Mechanical Engineering, 2021
Abstract. Sound field behaviour in an acoustic enclosure is an important part of the cabin passen... more Abstract. Sound field behaviour in an acoustic enclosure is an important part of the cabin passenger transport vehicle design, concert halls, conference rooms, etc., different analytical methods are available to design engineers, which has its strengths and weaknesses. Cavities in a low-frequency band and negligible absorption on the walls can be modelled by Modal Analysis and Finite Element Method. However, when the frequency band increases, both methods become computationally expensive and Statistical Energy Analysis or Sabine model can be an efficient approach. These methods assume deterministic treatment and almost nothing is known about the effect of uncertainties in the parameters, acoustic velocity and acoustic pressure inside cavities. This paper presents a study on the patterns of density and energy flow generated guide acoustic waves at high frequencies including uncertainties in geometric parameters and property of fluids. The waveguide is modelled by the Spectral Elemen...
As Engenharias frente a Sociedade, a Economia e o Meio Ambiente 5, 2020
Anais do X Congresso Nacional de Engenharia Mecânica, 2018
Anais do IX Congresso Nacional de Engenharia Mecânica, 2016
Proceedings of the Ninth International Conference on Computational Structures Technology