Design And Experimental Analysis Of Acoustic Insulation And Absorption Composite Honeycomb Sandwich Structure

High-speed train can cause serious noise influence on waiting hall when passingthrough high-speed railway elevated station. The noise sources of waiting hall includedirect sound incoming from the platform layer and indoor reverberation sound, and thebuilding roof is the main noise source. To improve the indoor acoustical environment,mounting the noise reduction structure to the ceiling is the most direct and effectivemeasure. So this paper proposes an acoustic insulation and absorption compositehoneycomb sandwich structure, and combines with theoretical analysis, simulation andexperimental test on the composite structure parameter design, finally verifies the noisereduction effect of the composite structure.In this paper, the acoustic insulation expression of the honeycomb sandwich plateis derived according to the principle of the sound propagation. Using acoustic indirectboundary element method to calculate the transmission loss of different specificationsof the honeycomb sandwich, studied the influence laws of parameters on the soundinsulation performance. Modal analysis method has been used to study the noisespectrum characteristics of the structure. Comparing with other structures, honeycombsandwich plate shows better low frequency sound insulation effect.The acoustoelectric analogy model of the microperforated panel is established; alsothe sound absorption coefficient of the structure has been calculated. It studies theprinciple of the peak of absorption coefficient, bandwidth of absorption coefficient, andresonance frequency changing with structural parameters. On this basis, it calculates thesound absorption coefficient of double-leaf micro-perforated structure, studies the lawshow cavity thickness combination influent the bandwidth of absorption coefficient andthe peak of absorption coefficient. Comparing with single-layer microperforatedstructure, the absorption bandwidth of double-leaf structure extends to the lowfrequency area, low frequency absorption effect is more pronounced.The transmission loss of honeycomb sandwich plate and the absorption coefficientof the microperforated–honeycomb composite panel are tested by using the impedancetube. By processing and testing the samples of different specification, it sums up therule that the noise reduction results of the two structures change with the parameters. Itcompares the simulation calculation result and test result of transmission loss of thehoneycomb sandwich structure, analyses the sound insulation effect in low frequencyarea that influenced by sealing and boundary conditions.The insulation structure parameters of the acoustic insulation and absorptioncomposite structure are designed according to the calculation result and test result of thehoneycomb sandwich plate. Also the acoustic absorption part is designed by orthogonal test method, the optimal parameter combination has been determined. The acousticinsulation and absorption composite structure is designed by combing with the studyresults of double-leaf microperforated structure and the absorption characteristics ofporous material, the cascade mode and main structural parameters are determined aswell. The equivalent surface density of the designed composite structure is calculated;also the transmission loss and absorption coefficient are tested. Calculation and testresults show that the designed acoustic insulation and absorption composite honeycombsandwich structure can meet the design goals and objectives.