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Acoustic Performance Analysis Of Two-dimensional Acoustic Black Hole Plate Structure

Posted on:2023-11-16Degree:MasterType:Thesis
Country:ChinaCandidate:Z J XieFull Text:PDF
GTID:2532306902980569Subject:Mechanical engineering
Abstract/Summary:PDF Full Text Request
Acoustic black hole structure is a kind of structure that realizes bending wave control by controlling its thickness in the form of power-law function,so as to realize effective noise reduction.Because of this characteristic,acoustic black holes are widely used in the field of noise reduction.The one-dimensional acoustic black hole structure is a power-law wedge-shaped structure.The two-dimensional acoustic black hole structure is formed by rotating one circle with the beam tip as the center on the basis of the one-dimensional acoustic black hole.In practical application,two-dimensional acoustic black hole plate structure has a wide prospect in the field of noise reduction.However,at present,the research on two-dimensional acoustic black hole plate is mainly in the field of practical application,but ignores the theoretical research on the bending wave reflection coefficient,sound pressure and sound pressure level of two-dimensional acoustic black hole plate,which can directly reflect the noise reduction effect.Taking this as the starting point,this paper makes an acoustic theoretical study on the most widely used isotropic and anisotropic two-dimensional acoustic black hole plate structure.The details are as follows:In this paper,the bending wave number of general two-dimensional plates is solved by combining Euler Bernoulli beam theory with geometric acoustic method,and then the bending wave numbers of the two specific models are obtained by combining the circular plate structure of circular hole embedded acoustic black hole and the rectangular plate structure of slot embedded acoustic black hole.By calculating the loss bending wave integral in the variable thickness region of the two specific models,the bending wave reflection coefficients of the two specific models are solved.Then,the structural characteristic parameters and material characteristic parameters of the two acoustic black hole models are analyzed.The influence of the length,width and depth of the variable thickness region of the acoustic black hole,as well as the material density,Young’s modulus and Poisson’s ratio on the flexural wave reflection coefficient is analyzed by using the control single variable method and the comparison method,so as to provide a reference for the structural design of two-dimensional acoustic black hole plate.Then,based on the isotropic two-dimensional acoustic black hole plate structure,the anisotropic two-dimensional acoustic black hole circular plate model is established to solve the bending wave reflection coefficient of the anisotropic two-dimensional acoustic black hole circular plate of the specific structure,and the influence of isotropic material and anisotropic material on the bending wave reflection coefficient is compared and analyzed.Finally,the two-dimensional acoustic pressure equivalent models of the sound pressure field and the sound pressure equivalent surface of the black hole are established in the specific acoustic pressure field.
Keywords/Search Tags:acoustic black hole plate, reflection coefficient, sound pressure, Geometric acoustics, Finite element analysis
PDF Full Text Request
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