Design And Optimization Of Acoustic Structure Based On Acoustic-Electric Matching

As people's willingness and demand for noise control become higher and higher,various products,especially high-end products,begin to study the sources and control methods of noise.Noise is a type of sound.Broadly speaking,it is generated by vibration,propagates in an elastic medium(including gas,liquid,and solid with elastic properties)and finally reaches the receiving device.Noise in construction machinery will accelerate the damage of machine parts and reduce processing accuracy.At the same time,human organs are very sensitive to low-frequency noise and will resonate with it,which will seriously affect human health.Therefore,it is necessary to study noise.At present,there are two main methods for noise control.One is to develop new sound-absorbing materials and use them as the outer wall of the pipeline or as the substrate material(such as glass wool,mineral wool,etc.).The sound absorption principle of this method is generally It is the porosity of the material.Another method is to achieve the sound attenuation effect through the resonance of the structure itself,such as Helmholtz resonance cavity,perforated plate,etc.This article mainly studies the structure of noise reduction.This article uses the finite element simulation software COMSOL to simulate and analyze the model based on the theory of acoustic and electrical matching,including comparing the experimental data in known literature to verify the feasibility of COMSOL software simulation.For the study of the influencing factors of resonance frequency,two dual-channel models have been designed.One is to add side branches and necks to the two branches of the dual channel,and the other is to add two helmholmes to the two branches of the dual channel Resonant cavity.Based on these two structures,this paper designs an acoustic structure with a center frequency of 600 Hz,a bandwidth of 600 Hz,a center frequency of 800 Hz,and a bandwidth of 600 Hz,and optimizes the structure by adjusting the structure parameters.Through research and simulation analysis,it is found that the resonance frequency and peak value of the Helmholtz resonator obtained by COMSOL simulation are within 1%of the experimental results in the literature,which proves the feasibility of COMSOL simulation.When a reference value is given,around the reference resonance frequency,the resonance frequency of the Helmholtz resonance cavity is proportional to(s is the neck diameter,?'is the effective length),and(V is the cavity volume of the resonance cavity)There is a strong linear relationship;when the length-to-diameter ratio of the resonant cavity is 0.1-1.5,the resonance frequency remains stable;the shape of the cavity has little effect on the resonance frequency.For the side-branch+neck dual-channel model,changing the side-branch structural parameters can change the resonance frequency,and changing the neck structural parameters can fine-tune the right-side passband curve;this structure will produce a sharp peak in the passband of the transmission loss curve This is due to the zero or pole generated by the simulation software when solving the parametric equation of the composite structure.Changing the neck structure parameters can also change the position and positive and negative peaks.The dual-channel-dual-holmholtz resonator cavity structure performs better in the transmission loss curve.By alternately arranging with the single-helmholtz resonator cavity,the transmission loss curve of the resulting structure is the same as the transmission loss of the same order Chebyshev filter The curves are relatively similar,especially in the frequency band around the resonance frequency;by increasing the resonance frequency of the dual-channel-dual Helmholtz cavity structure,reducing the resonance frequency of a single Helmholtz cavity can make the structure curve in the passband The steepness of the edge increases,increasing the degree of coincidence with the target curve.