Acoustic panel with one or more structural stiffeners

1. An acoustic panel, comprising:

a perforated first skin;

a second skin; and

a core including a first wall, a second wall and a stiffener;

the core forming a plurality of cavities that extend vertically between the perforated first skin and the second skin and that extend laterally between the first wall and the second wall, the plurality of cavities including a first cavity; and

the stiffener projecting partially into the first cavity, the stiffener and connected to the first wall and the second wall, and the stiffener comprising a flat panel that extends laterally across the first cavity from the first wall to the second wall.

2. The acoustic panel of claim 1 , wherein one or more perforations in the perforated first skin are fluidly coupled with the first cavity.

3. The acoustic panel of claim 2 , wherein

the first cavity forms a resonance chamber having a minimum length that extends between the perforated first skin and the second skin along a baffle; and

the minimum length is longer than a vertical thickness of the core.

4. The acoustic panel of claim 1 , wherein

the core further includes a plurality of baffles and a plurality of septums, the plurality of baffles include a first baffle and a second baffle, and the plurality of septums include a first septum;

the plurality of baffles are arranged in a longitudinal linear array, each of the plurality of baffles is connected to and extends laterally between the first wall and the second wall, and the first cavity extends longitudinally between the first baffle and the second baffle;

the plurality of septums are arranged in a longitudinal linear array, each of the plurality of septums is connected to and extends laterally between the first wall and the second wall, the first septum is disposed between the first baffle and the second baffle, and the first septum divides the first cavity into fluidly coupled first and second sub-cavities.

5. The acoustic panel of claim 4 , wherein the stiffener projects partially into the first sub-cavity and is between the first baffle and the first septum.

6. The acoustic panel of claim 1 , wherein an edge of the stiffener extends laterally along and parallel with the perforated first skin from the first wall to the second wall.

7. The acoustic panel of claim 1 , wherein the stiffener is arranged perpendicular to the first wall and the perforated first skin.

8. The acoustic panel of claim 1 , wherein the stiffener is configured with a triangular base that extends laterally across the first cavity.

9. The acoustic panel of claim 1 , wherein

the stiffener includes a base and a mount cantilevered from the base;

the base extends laterally across the first cavity; and

the mount is bonded to at least one of the first wall or the second skin.

10. The acoustic panel of claim 9 , wherein

the stiffener further includes a second mount cantilevered from the base; and

the mount is bonded to at least one of the second wall or the perforated first skin.

11. The acoustic panel of claim 1 , wherein an aperture extends longitudinally through the stiffener.

12. The acoustic panel of claim 1 , wherein

the plurality of cavities further include a second cavity longitudinally adjacent the first cavity; and

the core further includes a second stiffener projecting partially into the second cavity and connected to the first wall and the second wall.

13. The acoustic panel of claim 1 , wherein

the plurality of cavities further include a second cavity longitudinally adjacent the first cavity; and

the core is configured without a stiffener within the second cavity.

14. The acoustic panel of claim 1 , wherein the core comprises fiber-reinforced composite material.

15. The acoustic panel of claim 1 , wherein the perforated first skin, the second skin and the core form a component of an aircraft propulsion system.

16. An acoustic panel, comprising:

a first skin;

a second skin; and

a core including a first wall, a second wall and a stiffener;

the core forming a plurality of cavities, the plurality of cavities extending vertically along a z-axis between the first skin and the second skin, the plurality of cavities extending laterally along a y-axis between the first wall and the second wall, the plurality of cavities including a first cavity; and

the stiffener projecting partially into the first cavity, the stiffener extending vertically along the z-axis in a direction towards the first skin to an edge of the stiffener, and the edge of the stiffener extending parallel with the first skin as the edge of the stiffener extends laterally along the y-axis across the first cavity from the first wall to the second wall;

wherein an aperture extends longitudinally along an x-axis through the stiffener; and

wherein one or more perforations in the first skin are fluidly coupled with the first cavity.

17. The acoustic panel of claim 16 , wherein the stiffener is connected to the first wall and the second wall.

18. The acoustic panel of claim 16 , wherein the stiffener is connected to the first skin between the first wall and the second wall.

19. The acoustic panel of claim 16 , wherein the stiffener is arranged perpendicular to the first wall and the first skin.

20. An acoustic panel, comprising:

a perforated first skin;

a second skin; and

a core including a first wall, a second wall and a stiffener;

the core forming a plurality of cavities that extend vertically between the perforated first skin and the second skin and that extend laterally between the first wall and the second wall, the plurality of cavities including a first cavity; and

the stiffener projecting partially into the first cavity, the stiffener connected to the first wall and the second wall, and the stiffener extending vertically to the second skin.