Research On Sound Absorption Mechanism Of Non-smooth Surface Bionic Coupling Sound Package Material

With the development of industry,noise pollution,water pollution and air pollution are becoming more and more prominent.Environmental noise pollution has become one of the main factors hindering the development of industrial civilization.Sound package material has great effect on reducing the medium-high frequency and high frequency noise of automotive,so it is necessary to study the application of acoustic materials in automobile noise reduction.At present,the research on sound package materials is limited to the study of the smooth surface,and there is a vacancy in the study of sound package materials for non-smooth surface sound package materials.The study on sound absorption performance of sound packaging is very meaningful to satisfy the requirement of comfort and sound quality.Long ear owl wing surface,shark body surface and plant leaf surface were analyzed using bionics method based on the non-smoothness theory.Four typical non-smooth unit shapes were selected: triangular wedge,trapezoidal rib,trapezoidal pits and cylindrical projection unit body.The preferred non-smooth shape was applied to the acoustic package to produce a polyurethane foam with a non-smooth surface morphology.The sound absorption properties of non-smooth surface polyurethane foams were measured by standing wave tube method to study the effect of non-smooth surface on the sound absorption performance.In addition,the characteristic parameters of the sound material were determined by the test method and numerical calculation method,so as to prepare for the subsequent establishment of the porous material finite element model and model verification.Based on the extracted surface features of the biological surface,non-smooth surface sound absorption structure models were constructed using a polyurethane material as a matrix,and the sound absorption performance of the non-smooth surface porous sound-absorbing materials was simulated and analyzed based on the finite element method to study the sound absorption performance of a non-smooth surface.The impact was followed by the use of a triangular tip model as the research object to analyze the effect of surface morphology parameters on the sound absorption performance.Finally,a non-smooth surface coupled bionic model with a thickness of 30 mm and a cavity thickness of 10 mm was established to couple bionics.The mechanism of sound absorption was studied in depth.Triangular tip model was set as the research object,the average sound absorption coefficient and quality of acoustic packaging materials are taken as the optimization object,and the improved multi-objective optimization is performed using the improved grey correlation analysis.Firstly,through the orthogonal experiment analysis,the simulation results of each experimental group are obtained,and the grey relational degree is calculated through the traditional grey correlation analysis;then the radial basis neural network model of the grey relational degree is established,and the accuracy of the approximate model is verified to guarantee the feasibility and reliability of the optimization results;the particle swarm algorithm is used to obtain the combined values of the surface parameters of the triangular tip model in the presence of maximum gray correlation,and the optimal parameters of the optimized grey correlation analysis are assigned to the model.The feasibility of the improved algorithm was verified compared with the original grey correlation degree results.Based on the statistical energy analysis method,a statistical energy analysis model of the automotive bulkhead and floor was established.The non-smooth surface material was applied to the automotive bulkhead and floor to study the effect of non-smooth surface on sound absorption performance of automotive sound packaging.