Examinando por Materia "Elementos finitos"

Mostrando 1 - 7 de 7
  • Publicación
    Acceso abierto
    Análisis Acústico de un Recinto Variando su Geometría, por Medio del Método de Elementos Finitos.
    (2010) Barreiro Pérez, Julián Mauricio; Bodensiek Cuervo, Rainer Enrique; Hermida Cadena, Luis Fernando
  • Publicación
    Acceso abierto
    Análisis de resonadores de Helmholtz a partir de la implementación del método de elementos finitos
    (2019) Duque Salcedo, Andrés Felipe; Franco Bedoya, Ramiro Esteban
    The project consists of studying the acoustic and physical behavior of the Helmholtz resonators, which according to their dimensions can have different resonance frequencies. The analysis will be done by means of the finite element method (FEM), whose mathematical calculation model provides greater proximity to a real system; This is achieved through matrix arrays. The studies carried out to date on the finite element method focused on acoustics have been carried out for the modal analysis of enclosures, analysis of acoustic silencers for industrial machinery and is often used in the creation of electroacoustic prototypes, such as loudspeakers and microphones. In addition, this method has the advantage of coupling several physical phenomena, for example obtaining data about the temperature and at the same time the acoustics of some model, that is why this method is implemented for the characterization of acoustic materials such as the Helmholtz resonators. Initially, the equation of an acoustic wave is described, which makes it easier to show what is the behavior of the sound in a general way to later center said equation in a particular case, the Helmholtz resonators, which are described from the Helmholtz equation. After having raised the mathematical and physical problem, we proceed to solve it by the aforementioned method. The main advantages of using FEM to analyze materials such as Helmholtz resonators are in the optimization of this process in terms of time and money. In addition, it is vital to know that this method is recurrent as long as you have a processing capacity in the machines too high. The evaluation of the finite element method is performed in the simulation software comsol multiphysics using two different 3D models of Helmholtz resonators, each with different physical characteristics, the simple cavity resonator and the cavity resonator. simple based on slats. Each of the models will have four designs, two for low frequency and two for low medium frequency, having a total of eight simulations
  • Publicación
    Acceso abierto
    Auralización interactiva de barreras acústicas utilizando el método de acústica geométrica y elementos finitos
    (2019) Silva Carmona, Sergio; Moreno Gil, Andrés Felipe; Murillo Gómez, Diego Mauricio
    The present work aims to develop an interactive auralization system comprising the entire frequency range of human hearing. The objective is to auralize the screening effect produced by an acoustic barrier (AB). This objective was accomplished with the integration of two methods used to model the propagation of sound: Geometrical Acoustics (GA) and Finite Element (FE). This system allows users to move and rotate in a virtual environment perceiving the pressure variations of the sound field according to its spatial location. The inclusion of the FE method for the numerical solution of the wave equation is a consequence of the limitation of the GA method at low frequencies. In the addition, the use of this tool allows the calculation of the transmission loss (TL) of the acoustic barrier, as well as the estimation of the diffraction phenomenon. Based on the above arguments, a free-field domain was designed for both methods, with the assumption of anechoic boundary conditions. The following step was the synthesis of B-format signals that contain the spatial information of the domain. In GA, the creation of B-Format signals is done by the export of Wav files generated by the software. In the case of FE, it is done through the formulation of an inverse problem, that using discrete pressure data allows the determination of the synthesis of the complex spherical harmonic coefficients. After obtaining the B-Format signals in both GA and FE, a crossover to integrate the impulse responses (IR) obtained by both methods is designed. Additionally, an algorithm developed in Max and articulated with Unity software is created in order to generate a visual interface that allows the real-time spacialization of the effect of a AB based on the position and orientation of an avatar within a virtual environment. Finally, the result is the rendering of the sound pressure considering the effect of an AB by means of the two above mentioned methods. Consequently, a computational tool to auralize the screening effect generated of a AB in real-time is provided.
  • Publicación
    Acceso abierto
    Diseño y construcción de una guía de onda para un sistema de refuerzo sonoro implementado para una frecuencia de 1000 Hz
    (2015-11) Ladino Velásquez, Anderson; Torres Cifuentes, Manuel Fernando
    El objetivo principal de este proyecto es diseñar y construir una guía de onda para un sistema de refuerzo sonoro implementado en la frecuencia de corte del motor de compresión de 1000 Hz. Se desarrolla y se implementa una metodología para la medición del frente de onda, directividad, nivel de presión sonora, distorsión armónica y respuesta en frecuencia del dispositivo. Como parámetro de comparación se realizan mediciones del frente de onda analizando los retardos temporales y la amplitud de las señales con solo la radiación del motor de compresión, con la guía de onda de un fabricante y con la guía de onda propia; la metodología del frente de onda se realiza por medio de micrófonos a la salida de los dispositivos y en el campo tridimensional (X, Y, Z) a 0,5 metros, 1 metro, 1,5 metros y 2 metros a diferentes longitudes de onda a una frecuencia de 1 KHz. Se realiza otra metodología por medio de elementos finitos diseñando ambas guías de onda en 3D y 2D para observar el comportamiento del frente de onda y la directividad.
  • Publicación
    Acceso abierto
    Evaluación de auralizaciones obtenidas combinando métodos de elementos finitos y acústica geométrica en dos recintos y su aplicación en la valoración acústica de uno de ellos
    (2015) Rodríguez Villota, Juan Camilo; Naranjo Ruiz, Anderson; Tafur Jiménez, Luis Alberto
    En el presente trabajo se desarrolla ideas de investigaciones anteriores; por lo tanto se hace énfasis en la evaluación de auralizaciones obtenidas combinando métodos de elementos finitos y acústica geométrica para dos recintos diferentes y aplicarlas en la valoración acústica de uno de ellos. Como recintos objeto de investigación se usa un salón del ISVR (por sus siglas en ingles Institute of Sound and Vibration Research), salón de reuniones amoblado con un volumen de 75 m3, y el mini auditorio 2 de la Universidad San Buenaventura Medellín, salón de clases con un volumen de 135 m3 y estado de ocupación vacío. Respuestas al impulso obtenidas mediante FEM y acústica geométrica para ambos recintos, estímulos semi anecoicos para ser reproducidos en las auralizaciones, y listas anecoicas de logatomos (palabras sin sentido de una sílaba constituidos por consonante-vocal-consonante); son datos usados del semillero de investigación del programa la Universidad San Buenaventura Medellín e investigaciones anteriores de compañeros de carrera [3], [4] y [5], sin los cuales no hubiera sido posible desarrollar este proyecto; y a partir de estos, se crean auralizaciones para varias posiciones de receptor en cada recinto. Además, se realizan mediciones de respuestas al impulso binaurales (RIBs) y monoaurales (RIs) en el mini auditorio 2. Las auralizaciones del primer recinto, el salón de reuniones, son usadas para la prueba subjetiva (con una muestra de 40 personas para evaluar auralizaciones que combinan FEM y acústica geométrica, y 20 personas para evaluar auralizaciones de acústica geométrica); mientras que las del segundo, el salón de clases, se usan para evaluar el impacto de las condiciones acústicas en la inteligibilidad de la palabra y dificultad de escucha del recinto en una muestra de 40 personas, en dos condiciones acústicas diferentes; la actual y con propuesta de acondicionamiento acústico. Además, se realiza una prueba objetiva de acuerdo al estándar ISO 3382 para ambos recintos y se presenta el procedimiento estadístico de los datos y su respectivo análisis. Posteriormente, se encuentra que las auralizaciones que combinan elementos finitos y acústica geométrica tienden a presentar mejoras en frecuencias bajas con respecto auralizaciones que solamente usan acústica geométrica, lo cual se ve reflejado en la evaluación objetiva en las bandas de 125 y 500 Hz, principalmente en el salón de reuniones del ISVR; y en la prueba subjetiva en el parámetro calidez; además, se encuentra que el atributo mejor calificado en la prueba subjetiva es la localización. Adicionalmente, los resultados de evaluar el impacto de las condiciones acústicas en el mini auditorio 2 presentan un incremento en la inteligibilidad de la palabra y una disminución de dificultad de escucha para las auralizaciones con acondicionamiento acústico frente a las auralizaciones de la condición actual del recinto.
  • Publicación
    Acceso abierto
    Implementación del método de elementos finitos como técnica parala generación de Beamforming
    (2020) Otalvaro Barco, Santiago; Fernández Parra, Daniel José; Murillo Gómez, Diego Mauricio
    This work implements the FEM finite element method for the generation of simulations that allows the studyof the acoustic behavior of a speaker array that produces beamforming. The selection of the finite elementmethod is made with the purpose of taking into account the considerations of the wave phenomena in the designof the acoustic box. This process starts from a simulation in MATLAB software where free field conditionsare established with analytical elementary solutions based on monopoles and pistons. The input parameters,such as the volumetric flow(Qs)in a monopole and the normal velocity(Vn) in a piston, are obtained fromthe simulations with Matlab and entered into the simulation software with FEM to corroborate that thebehavior of both simulations obtained similarities in the results. The implementation of FEM is accomplishedby means of the election of suitable parameters, according to the discretization of the domain, to obtain acorrect estimation of the phenomenon under study. The amplitude values of the sources for beamforminggeneration are proposed when solving the inverse method. This generates amplitudes from control variablesthat determine the propagation in a given area. The method is evaluated by means of acoustic simulationsoftware with FEM. The results indicate that the finite element method is a technique that is used to efficientlyevaluate the design of an array of speakers that generate beamforming. Wave phenomena such as box diffractioncan be contemplated in what shows a complex algorithm for electroacoustic design, however, the solution isefficient when the computational load of the simulations does not exceed the calculation capacity.
  • Publicación
    Acceso abierto
    Ubicación estratégica de material absorbente basado en el análisis modal de una sala
    (2019) Tapias Pinzón, Diego Alejandro; Berrío Bernal, Juan David
    This grade work was carried out in order to test the hypothesis that the location of the absorbent material at the absolute sound pressure maxima of a room decreases the reverberation time in the octave band to which the mode frequency belongs. The results obtained in the reverberation time T_15 and T_20 of a room in the 125 Hz octave band are presented, in which, by means of a modal analysis, the location of the absorbent material was varied in order to obtain the maximum absorption of sound energy. For its implementation it was necessary to carry out a survey of a 3D model of the room and import it into a finite element simulation software, with which the absolute maximum and minimum sound pressure was determined. A simulation was then carried out in the CATT-Acoustics v9.1 software, in which two panel configurations were tested, one in which the absorbent material was placed at absolute maximum pressure and the other at minimum pressure. After the simulation, a measurement based on an experimental design was performed. The measurement involved 18 combinations of source location, microphones and absorber panel configuration, after which the responses to the impulse of each combination were found by means of the MATLAB software and the reverberation time for each measurement point was estimated consecutively by means of the plug-in aurora software Audacity 2.0.5. Finally, a statistical analysis was performed to determine the factors that were statistically significant in the measurement results.