Pressure vessel having substantially flat panel

1. A pressure vessel, comprising:

at least one pair of side bulkheads spaced apart from each other and each having a bulkhead top portion;

at least one substantially flat panel having at least one panel span extending between the pair of side bulkheads and being in non-contacting proximity to the bulkhead top portions, the panel and the side bulkheads collectively forming at least a portion of a structural assembly enclosing the pressure vessel; and

a first plurality of panel braces coupling each of the side bulkheads to the panel at a corresponding first plurality of panel attachment nodes distributed along the panel span, at least two of the panel braces of the first plurality of panel braces having a different axial stiffness configured to result in an outward deflection of the first plurality of panel attachment nodes by substantially equal deflection amounts when the panel is subjected to an out-of-plane pressure load during internal pressurization of the pressure vessel.

2. The pressure vessel of claim 1 , further including:

at least one vessel rib located between the pair of side bulkheads and having a rib top portion in non-contacting proximity to the panel; and

the at least one vessel rib coupled to the panel using a second plurality of panel braces extending from the rib top portion to a second plurality of panel attachment nodes distributed along the panel.

3. The pressure vessel of claim 1 , wherein at least one panel brace of the first plurality of panel braces coupling one of the side bulkheads to the panel has at least one of the following configurations:

a cross-sectional area and a corresponding axial stiffness that is different than a cross-sectional area and a corresponding axial stiffness of one or more of the remaining panel braces of the first plurality of panel braces coupling the pair of side bulkheads to the panel; and

an elastic modulus and a corresponding axial stiffness that is different than an elastic modulus and a corresponding axial stiffness of one or more of the remaining panel braces of the first plurality of panel braces coupling the pair of side bulkheads to the panel.

4. The pressure vessel of claim 1 , wherein:

a panel brace of the first plurality of panel braces coupling one of the side bulkheads to the panel at a panel attachment node of the first plurality of panel attachment nodes nearest the one of the side bulkheads has a lower stiffness than the remaining first plurality of panel braces coupling the one of the side bulkheads to the panel.

5. The pressure vessel of claim 1 , wherein:

the first plurality of panel attachment nodes are non-uniformly spaced along the at least one panel span.

6. The pressure vessel of claim 1 , wherein:

at least two of the first plurality of panel braces extending from one of the at least one pair of side bulkheads are attached to the bulkhead top portion at a single brace-bulkhead attachment location.

7. The pressure vessel of claim 1 , further including:

at least one pressure containment mechanism configured to seal the panel to at least one of the pair of side bulkheads for internal pressurization of the pressure vessel.

8. The pressure vessel of claim 1 , wherein:

at least one of the panel and the first plurality of panel braces is configured for fail-safety to prevent failure of the panel in event of a failure of one of the first plurality of panel braces.

9. The pressure vessel of claim 8 , wherein the fail-safe configuration comprises at least one of the following:

at least one of the first plurality of panel braces has an axial strength capability to prevent failure of the panel in event of a failure of another one of the first plurality of panel braces;

at least one of the first plurality of panel braces has a residual axial strength and a residual axial stiffness capability to prevent failure of the panel in event of a failure of the at least one of the first plurality of panel braces; and

the panel has a bending load capability to prevent failure of the panel in event of a failure of one of the first plurality of panel braces.

10. The pressure vessel of claim 1 , wherein:

the pressure vessel comprises at least one of a passenger cabin and a cargo hold of an aircraft; and

the panel comprising a skin panel defining an aerodynamic surface of the aircraft and configured to sustain flight loads during pressurization of at least one of the passenger cabin and the cargo hold.

11. A method of loading a pressure vessel, comprising:

internally pressurizing the pressure vessel at least partially enclosed by a panel having at least one panel span extending between a pair of side bulkheads each having a bulkhead top portion in non-contacting proximity to the panel;

generating an out-of-plane pressure load on the panel in response to internally pressurizing the pressure vessel;

transmitting the out-of-plane pressure load from the panel to the pair of side bulkheads using a first plurality of panel braces coupling individual ones of the side bulkheads to the panel at a first plurality of panel attachment nodes distributed along the at least one panel span; and

limiting an outward deflection of the first plurality of panel attachment nodes to substantially equal deflection amounts when internally pressurizing the pressure vessel, the outward deflection being limited by the first plurality of panel braces having an axial stiffness that is different among at least two of the panel braces of the first plurality of panel braces.

12. The method of claim 11 , further comprising:

transmitting the out-of-plane pressure load from the panel to at least one vessel rib using a second plurality of panel braces coupling a rib top portion to a second plurality of panel attachment nodes distributed along the at least one panel span, the at least one vessel rib located between the pair of side bulkheads and being in non-contacting proximity to the panel.

13. The method of claim 11 , wherein transmitting the out-of-plane pressure load from the panel to the pair of side bulkheads includes:

transmitting the out-of-plane pressure load using at least one panel brace of the first plurality of panel braces having at least one of the following configurations:

a cross-sectional area and a corresponding axial stiffness that is different than a cross-sectional area and a corresponding axial stiffness of one or more of the remaining panel braces of the first plurality of panel braces coupling the pair of side bulkheads to the panel; and

an elastic modulus and a corresponding axial stiffness that is different than an elastic modulus and a corresponding axial stiffness of one or more of the remaining panel braces of the first plurality of panel braces coupling the pair of side bulkheads to the panel.

14. The method of claim 11 , wherein in event of a failed brace among the first plurality of panel braces, the method further comprising at least one of the following:

carrying, in one or more remaining panel brace of the first plurality of panel braces, an axial load higher than an axial load carried by any of the first plurality of panel braces when none have failed, for preventing failure of the panel due to buckling;

carrying an axial load in the failed brace capable of preventing failure of the panel; and

carrying, in the panel, a bending load higher than a bending load carried by the panel when none of the first plurality of panel braces have failed, for preventing failure of the panel due to buckling.

15. The method of claim 11 , wherein the pressure vessel comprises at least one of a passenger cabin and a cargo hold of an aircraft, the panel comprising an aerodynamic surface, the method further comprising:

sustaining, using the panel, flight loads imparted upon the panel during pressurization of at least one of the passenger cabin and the cargo hold.

16. A method of manufacturing a pressure vessel, comprising:

positioning a pair of side bulkheads in a spaced relation to each other, the pair of side bulkheads each having a bulkhead top portion;

positioning a substantially flat panel in non-contacting proximity to the bulkhead top portion of each of the pair of side bulkheads such that at least one panel span extends between the pair of side bulkheads, the panel and the pair of side bulkheads collectively forming at least a portion of a structural assembly enclosing the pressure vessel; and

coupling, using a first plurality of panel braces, each of the side bulkheads to the panel at a corresponding first plurality of panel attachment nodes distributed along the panel span, at least two of the panel braces of the first plurality of panel braces having a different axial stiffness that results in an outward deflection of the first plurality of panel attachment nodes by substantially equal deflection amounts when the panel is subjected to an out-of-plane pressure load during internal pressurization of the pressure vessel.

17. The method of claim 16 , further including:

positioning at least one vessel rib between the pair of side bulkheads such that the panel is in non-contacting proximity to a rib top portion; and

coupling the at least one vessel rib to the panel using a second plurality of panel braces extending from the rib top portion to a second plurality of panel attachment nodes distributed along the panel.

18. The method of claim 16 , wherein coupling each of the side bulkheads to the panel at the first plurality of panel attachment nodes includes:

coupling each of the side bulkheads to the first plurality of panel attachment nodes, wherein the first plurality of panel attachment nodes are non-uniformly spaced along the panel span.

19. The method of claim 16 , wherein coupling each of the side bulkheads to the panel at the first plurality of panel attachment nodes includes:

coupling the side bulkheads to the panel using the first plurality of panel braces having at least one of the following configurations:

a cross-sectional area and a corresponding axial stiffness that is different than a cross-sectional area and a corresponding axial stiffness of one or more of the remaining panel braces of the first plurality of panel braces coupling the panel to the pair of side bulkheads; and

an elastic modulus and a corresponding axial stiffness that is different than an elastic modulus and a corresponding axial stiffness of one or more of the remaining panel braces of the first plurality of panel braces coupling the panel to the pair of side bulkheads.

20. The method of claim 16 , wherein coupling each of the side bulkheads to the panel at the first plurality of panel attachment nodes includes at least one of the following:

coupling the pair of side bulkheads to the panel using one or more panel braces of the first plurality of panel braces having an axial strength capable of preventing failure of the panel in event of a failed panel brace of the first plurality of panel braces;

coupling the pair of side bulkheads to the panel using at least one panel brace of the first plurality of panel braces having a residual axial strength capability and a residual axial stiffness capability to prevent failure of the panel in event of a failure of the same panel brace; and

coupling the pair of side bulkheads to the panel having a bending load capability value higher than a bending load carried by the panel when none of the panel braces of the first plurality of panel braces have failed.