As a new functional material, foam aluminum is of characteristics of sound absorption and vibration attenuation. A type of composite structure consisting of a foam aluminum layer and base plates is put forward. The sound insulation performance is investigated. The method for computation of sound transmission loss for normal wave incidence is developed. The influences of different thickness of the foam aluminum layer on the transmission loss of the structure are analyzed by numerical method. The results are in good agreement with those of experimental testing. It is found that the thickness of foam aluminum has a great impact on the sound transmission loss of the composite structure.

For traditional chute vibration and noise is very large, chute with viscoelastic damping layer free on it is designed. In this paper, hammer excitation method and the LMS test. Lab vibration test system are used to carry out modal testing for chute with viscoelastic damping layer. In this test, we find the former six ranks mode frequencies，damping and modal shape of the chute. The test of MAC matrix proves that the experimental modal parameters measured are true and valid. It is found by analysis of the result that the vibration on the exit of the chute is lapped over by the torsional vibration and bending vibration. It should be strengthened to reduce the local vibration. The results offer reference for the optimization design of chute with viscoelastic damping layer free on it