Footwear incorporating a composite shell sole structure

1. An article of footwear having an upper and a sole structure secured to the upper, the sole structure comprising:

a shell having a ground portion and a footbed portion, a periphery of the footbed portion being secured to the ground portion to define a cavity between the ground portion and the footbed portion, the shell being formed from a composite material;

a core located within the cavity and substantially filling the cavity, the core being formed from a polymer foam material; and

mounting hardware for a cleat, the mounting hardware attached directly to the ground portion and having a top surface completely covered by the core.

2. The article of footwear recited in claim 1 , wherein the shell extends around and encloses substantially all of the core.

3. The article of footwear recited in claim 1 , wherein the ground portion of the shell forms at least a portion of a ground-contacting surface of the footwear.

4. The article of footwear recited in claim 1 , wherein the mounting hardware extends only through the ground portion of the shell.

5. The article of footwear recited in claim 1 , wherein a portion of the shell located in a heel region of the footwear extends upward and joins with the upper to form a heel counter.

6. The article of footwear recited in claim 1 , wherein the ground portion of the shell forms a portion of a lower surface and a side surface of the sole structure, and the footbed portion forms a portion of an upper surface of the sole structure.

7. The article of footwear recited in claim 1 , wherein the composite material of the shell includes a polymer matrix and carbon fiber reinforcement with a tensile strength greater than 0.60 gigapascals.

8. The article of footwear recited in claim 7 , wherein the core directly contacts one of the polymer matrix and carbon fiber reinforcement.

9. The article of footwear recited in claim 7 , wherein the fiber reinforcement includes layers of a textile, the ground portion incorporating a greater number of the layers of the textile than the footbed portion.

10. The article of footwear recited in claim 1 , wherein the sole structure includes a supplemental layer that extends between the footbed portion of the shell and a lower area of the upper.

11. An article of footwear having an upper and a sole structure secured to the upper, the sole structure comprising:

a shell formed from a composite material having a polymer matrix and fiber reinforcement with a tensile strength greater than 0.60 gigapascals, the shell including:

(a) a ground portion having a convex outer surface and an opposite concave inner surface, at least a portion of the outer surface forming a portion of an exterior surface of the sole structure,

(b) a footbed portion having an upper surface that faces the upper and an opposite lower surface, the footbed portion being joined to the inner surface of the ground portion to form an integral, one-piece unit, and the footbed portion extending continuously between opposite sides of the inner surface and continuously along a length of the sole structure, and

(c) a cavity located between the inner surface of the ground portion and the lower surface of the footbed portion,

each of the ground portion, footbed portion, and cavity extending through a majority of a length and a width of the sole structure;

a core formed from a polymer foam material, the core being located within the cavity and substantially filling the cavity; and

mounting hardware extending through and attached directly to the ground portion of the shell, the core completely covering a top surface of the mounting hardware.

12. The article of footwear recited in claim 11 , wherein the shell extends around and encloses substantially all of the core.

13. The article of footwear recited in claim 11 , wherein the core directly contacts the top of the mounting hardware.

14. The article of footwear recited in claim 11 , wherein the core directly contacts one of the polymer matrix and carbon fiber reinforcement.

15. The article of footwear recited in claim 11 , wherein the ground portion extends upward and joins with the upper to form a heel counter in a heel region of the footwear.

16. The article of footwear recited in claim 11 , wherein the footbed portion is contoured such that the upper surface defines a depression in a heel region of the footwear and a protruding area in a midfoot region and on a medial side of the footwear.

17. The article of footwear recited in claim 11 , wherein the fiber reinforcement includes layers of a textile, the ground portion incorporating a greater number of the layers of the textile than the footbed portion.

18. An article of footwear having an upper and a sole structure secured to the upper, at least ninety percent of a mass of the sole structure comprising:

a shell formed from a composite material including a polymer matrix and fiber reinforcement with a tensile strength greater than 0.60 gigapascals, the shell having a ground portion and a footbed portion joined together to define an interior cavity;

a core formed from a polymer foam material, the core being located within the cavity and substantially filling the cavity; and

mounting hardware for a cleat, the mounting hardware attached directly to the ground portion and having a top surface completely covered by the core.

19. The article of footwear recited in claim 18 , wherein the shell is an integral, one-piece unit.

20. The article of footwear recited in claim 19 , wherein the fiber reinforcement includes layers of a textile, the ground portion incorporating a greater number of the layers of the textile than the footbed portion.

21. The article of footwear recited in claim 18 , wherein the shell extends around and encloses substantially all of the core.

22. The article of footwear recited in claim 18 , wherein a portion of the shell located in a heel region of the footwear extends upward and joins with the upper to form a heel counter.