镁合金材料具有密度小、比刚度高、阻尼大、抗冲击性好等优势，已成功用于汽车仪表板。应用结构-声耦合法分析仪表板的隔声性能，可避免传统理论求解对模型的苛刻要求和实验条件的限制。通过与实验结果比较，证实结构—声耦合法预测结构隔声性能的可靠性，并得出了扩散声场内汽车仪表板传声损失的数值结果。结果表明，在低频段，相同面密度的压铸镁合金仪表板的隔声性能明显优于钢质仪表板。换用轻质镁合金材料后，需改进原有的结构，使仪表板的固有频率避开噪声源的峰值频段，避免结构在某些频段内的声学特性恶化。采用镁合金材料可在满足汽车减重要求的同时，改善驾驶室内的声学环境。

Magnesium alloy is light, and has large specific stiffness, great damping and excellent shock absorption. It had been made into automotive dash successfully. In order to avoid severe requirements of theoretical model and experiment condition limits, sound insulation performance of dash could be obtained by structure-sound interaction method. This approach was validated by comparing the numerical solutions with experimental results. Sound transmission loss of automotive dash in diffuse field was computed. The results indicated that in low frequency band, comparing with steel based dash, sound insulation performance of magnesium alloy based dash is much better. Replacing steel by magnesium alloy, original structure of dash needs to be improved, and its eigenfrequency should be beyond the peaks of noise source, avoiding deterioration of acoustic characteristic in certain frequency bands. Applying magnesium alloy to vehicle could lose weight as well as improve cab’s acoustic environment.