Sound transmission of double-wall active sound package with porous materials based on (u,p) formulation

A method based on the combination of the (u,p) formulation and finite element method is applied to calculating the acoustical performance of double-wall active sound packages with porous materials.The (u,p) formulation based on the displacement in solid phase and the pressure in fluid phase is developed to investigate sound propagation in porous materials.The acoustic performance of the double-wall active sound packages having porous materials was calculated and the measurement was taken.The numerical results matched well with the measured data.More than 10 dB of the transmission loss of the double-wall active sound packages can be improved in the resonance frequency with active control,and its absorption coefficient is up to 0.6 over 500 Hz.The relative error between the prediction and measurement is less than 5%in the resonance frequency of the porous materials.