Examinando por Materia "Finite elements"

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  • 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
    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.