Figure 1.

Gradient fluid-solid superlattice (a)Structure schematic diagram (b)The filling fraction distribution function diagram"

Figure 2.

Theoretical calculation results of sound transmission characteristics of GFSL structure (a)Transmission spectrum (b)Transmittance of periodic structure and GFSL structure when the sound wave is incident vertically"

Figure 3.

Transmittance of GFSL structure at incident angles of 10°, 30°, 50°and 70°"

Figure 4.

The transmittance of GFSL structure with the period number N is equal to 7, 13, 19 and 41 when the sound wave is incident vertically"

Figure 5.

The transmittance of GFSL structure with gradient function slope change when the sound wave is incident vertically (a)Maximum υm change (b)Minimum υ0 change"

Figure 6.

Transmittance of GFSL structure when the sound wave is incident vertically (a~b)The number of solid layers on both sides is the same, but the change of filling fraction gradient is different (c~d)The gradient change of filling fraction of solid layers on both sides is the same, but the number of layers is different"

Figure 7.

Transmission spectrum of GFSL structure with filling fraction as quadratic function gradient distribution"

Figure 8.

Theoretical and simulation results of transmittance of GFSL structure when the sound wave is incident vertically"

Figure 9.

Sound pressure field of GFSL structure at oblique incidence angle (a)10° (b)20° (c)30°"

Figure 10.

Filtering performance test (a)Input signal (b)Output signal"