Based on the transfer matrix method

a different backing situation of underwater isolating-sound and decoupled cover model is established.The sound absorption performance of isolating-sound and decoupled tile is discussed under soft backing

rigid backing

single-shell and double-shell backing.The results show that the absorption coefficient curve marks modulation behavior under double-shell backing

the water layer between the shells thickens and absorption peak value moves to low frequency.In addition

the number of peak increases and concentrates

the peak value also drops.The absorption coefficient is little influenced by the outer shell thickness.Under single-shell backing conditions the more the thickness of the shell plate is

the less the first absorption peak value is

and the peak moves to lower frequency.When the plate thickness is up to a certain thickness

the absorption coefficient curve gradually approached that in rigid backing.