Study Of Dimensional Effects On The Sound Insulation Performance Of Plate Structures

In recent years,with the rapid development of China’s high-speed railway and the improvement of people’s living standards,high-speed rail has gradually become the preferred mode of transportation for national travel.While people are pursuing higher speeds,they also put forward new requirements for the comfort of the riding environment.Therefore,how to reduce the noise level in the train has become a key issue that needs to be solved urgently.In engineering,limited by the size of the structure,which often uses the same attribute of the sound insulation of small size plate instead of large parts of the sound insulation,the validity and accuracy of this way of evaluating the sound insulation performance of the structure will certainly be questioned.In addition,field test methods are often used to obtain the sound insulation of large structure,such as high-speed train compartment structure,but they are severely affected by the environment and have low accuracy.Therefore,it is of great significance to study the influence mechanism of structure size on sound insulation,and obtain the internal relationship between sound insulation and surface size,so as to provide reference for the prediction of sound insulation performance in engineering application.Based on the relevant basic theories,this paper uses analytical methods to study the relationship between the acoustic response of the panel structure and the size,and solves the problem that the components in the project are limited by the size,and the reverberation room test cannot be used to accurately obtain the sound insulation.Firstly,according to the vibration theory,derive the vibration response amplitude relationship between the thin plates with the same proportional size change under the constraint of the four-sided simply supported boundary,and carry out the modal and steady-state response analysis;When the structure is forced to vibrate,energy will be radiated to the other side.According to the radiation theory,the power function change relationship between the modal acoustic radiation efficiency at the resonance frequency and the plate width and shape characteristics is derived.Then,the coupling relationship between the radiation efficiency of modal sound and the size and frequency is obtained.The acoustic radiation efficiency of each plate under the excitation of simple harmonic force and plane wave is obtained through simulation.Since sound is generated by vibration,based on the vibration response relationship and the sound insulation theory,the sound insulation volume-size model of thin plate under the joint action of overall vibration and bending vibration is established with acoustic impedance rate as the intermediate variable,and the effect law of size change on the sound insulation volume can be obtained,especially at the resonance frequency.This effect exists mainly at the boundary of the structure and is described by the elasticity and damping coefficients.This effect exists mainly at the boundary of the structure,which is described by the elasticity and damping coefficients.A four-sided simply-supported simulation device is designed,and the loss factor and sound insulation volume of each experimental plate are obtained through experimental tests,then the accuracy of the model is verified.Finally,a simple prediction was made on the sound insulation performance of the hollow profile of high-speed trains.The expression of the sound insulation of the doublelayer plate structure and the equivalent problems of different forms of plate structure are given,and the equivalent forms under the conditions of stiffened form and additional damping material are considered,and the hollow section is simplified into double-layer plate + stiffened plate In the form of,the acoustic impedance ratio is introduced,and the law of the change of sound insulation with size is derived,and the sound insulation performance of the aluminum profile plate structure is predicted.