高寒区高速列车阻尼铝型材低温环境下隔声特性研究

Analysis of Sound Insulation Performance of Extruded Aluminum with Damping Layers in Low Temperature Environments

随着环境温度的降低,含阻尼层铝型材的隔声性能逐渐降低。通过理论分析阐明传播媒质特性阻抗对隔声的影响。通过隔声试验,分析从20℃变化到-40℃含阻尼层铝型材在400 Hz~2 500 Hz 1/3倍频程的隔声规律。建立含阻尼层铝型材的有限元模型,进行温度场仿真计算、隔声仿真技术和阻尼优化设计。理论分析表明:温度降低使空气特性阻抗增大,进而隔声量降低。试验结果表明:2 000 Hz频段的隔声量对温度变化最为敏感,灵敏度达0.17dB/℃,其次是2 500 Hz频段和500 Hz频段。仿真优化表明:使用耐低温阻尼替换原阻尼,可明显提高低温环境下的隔声量。

As temperature decreases, the sound insulation capacity of extruded aluminum with damping layers gradually decreases. In this paper, the effect of the characteristic impedance of the medium on sound insulation is clarified theoretically. Through the test, the sound insulation performance of extruded aluminum with damping layers from 20 ℃ to-40 ℃ at 400 Hz-2 500 Hz 1/3 octave is revealed. Finite element model of the extruded aluminum is established, the temperature field is simulated, sound insulation technique and damping optimization are designed. Theoretical analysis shows that temperature decreasing can increase the characteristic impedance of the air, thereby reduce the sound insulation. The test results show that the sound insulation in the 2 000 Hz frequency band is most sensitive to the temperature change, the sensitivity can reach 0.17 dB/℃, followed by 2 500 Hz and 500 Hz frequency bands. Simulation optimization shows that the extruded aluminum is an orthotropic structure. Using low-temperature-resistant damping material instead of the original damping material can significantly improve the sound insulation capacity in low temperature environments.