非对称夹芯板隔声量的解析计算模型及影响因素

提出了一种计算上下面板非对称的三明治夹芯板隔声性能的方法。通过对非对称夹芯梁表观抗弯曲刚度的计算,得到对应夹芯板随频率变化的表观抗弯刚度,代入4阶的控制方程,应用模态展开法可以方便地计算简支非对称夹芯板的隔声量。对4种定制的3层非对称碳纤维夹芯板进行了理论计算和实验测试对比,在频率范围100~3150 Hz内,计权隔声量误差在3 dB以内。着重分析了面板对称性、芯层剪切模量对隔声性能的影响,发现在夹芯板面密度一定时,芯层剪切模量对夹芯板的隔声性能影响最为显著。当芯层剪切模量较小时,上下面板非对称分布导致吻合频率显著降低,对夹芯板的整体隔声亦不利。 

An analytical calculation model and influencing factors for sound insulation of asymmetric sandwich plates

An approach for the prediction of the sound transmission through asymmetric sandwich plates is proposed.Through the calculation of the apparent bending stiffness of the asymmetric sandwich beam,the frequency-dependent bending stiffness of the corresponding sandwich plate is obtained,and by substituting the fourth-order governing equation,the sound transmission loss of asymmetric sandwich plate can be easily calculated by applying the modal expansion method.Four customized sandwich plates with carbon fiber sheets and polymethacrylimide core layer are compared through theoretical calculations and experimental tests.The error between the predicted and measured weighted sound reduction index is less than 3 dB in the frequency range of 100 Hz to 3150 Hz.The influences of symmetry of the sheets and the shear modulus of core on the sound transmission loss of sandwich plates are discussed.It is found that the shear modulus of the core has the most significant influence on the Transimission Loss(TL) when the surface density of the composite plate is constant.When the shear modulus of the core layer is small,the asymmetry of sheets results in a significant decrease in the coincidence frequency,which is also detrimental to the overall sound transmission of the sandwich panel.