Composite blade root lay-up

1. A blade for a gas turbine engine, the blade having a neck flaring to a root, the blade comprising:

composite layers including uni-directional layers extending through the neck and the root, the uni-directional layers having adjacent surfaces spaced apart circumferentially from one another by a wedge-shaped gap that extends from an apex to an innermost radial end of the root, and a fabric compliant wedge layer arranged in the gap and joining the adjacent surfaces of the uni-directional layers, the fabric compliant wedge layer is uninterrupted in extending circumferentially at the innermost radial end to join the adjacent surfaces, the fabric compliant wedge layer has a reduced compressive Young's modulus compared to the uni-directional layers.

2. The blade according to claim 1 , wherein the composite layers are provided by a matrix composite material.

3. The blade according to claim 2 , wherein the matrix composite material is integrated with fibers.

4. The blade according to claim 2 , wherein the fabric compliant wedge layer is provided in the root, the uni-directional layers and the compliant wedge layer are integrated into a unitary matrix composite structure.

5. The blade according to claim 4 , wherein the fabric compliant wedge layer extends axially to an end face of the root.

6. The blade according to claim 1 , wherein the uni-direction layers extend in a generally radial direction to provide an airfoil.

7. The blade according to claim 6 , wherein uni-direction layers includes a matrix composite material having fibers extending in the radial direction, and the fabric compliant wedge layer includes a matrix composite material having fibers extending in a direction transverse to the radial direction.

8. The blade according to claim 7 , wherein the fabric compliant wedge layer is woven.

9. The blade according to claim 7 , wherein the fabric compliant wedge layer is non-woven.

10. The blade according to claim 1 , wherein the fabric compliant wedge layer has a tapered cross-section.

11. The blade according to claim 1 , wherein the fabric compliant wedge layer is 50%-90% of theoretical density.

12. The blade according to claim 11 , wherein the fabric compliant wedge layer has a compressive Young's modulus less than 75% of the uni-directional layers.

13. The blade according to claim 12 , wherein the fabric compliant wedge layer has a compressive Young's modulus in the range of 25-50% of the uni-directional layers.

14. A rotating stage of a gas turbine engine comprising:

a rotor including a slot; and

a blade having a root received in the slot, and a neck flaring to the root, the blade having composite layers including uni-directional layers extending through the neck and the root, the uni-directional layers having adjacent surfaces spaced apart circumferentially from one another by a wedge-shaped gap that extends from an apex to an innermost radical end of the root, and a fabric compliant wedge layer arranged in the gap and joining the adjacent surfaces of the uni-directional layers, the uni-direction layer extending through the neck and the root, and the fabric compliant wedge layer provided in the root, the uni-directional layers and the fabric compliant wedge layer are integrated into a unitary matrix composite structure, wherein the uni-direction layers extends in a radial direction to provide an airfoil, wherein uni-direction layers include a matrix composite material having fibers extending in the generally radial direction, and the fabric compliant wedge layer is uninterrupted in extending circumferentially at the innermost radial end to join the adjacent surfaces, the fabric compliant wedge layer includes a matrix composite material having fibers extending in a direction transverse to the radial direction, the fabric compliant wedge layer has a reduced compressive Young's modulus compared to the uni-directional layers.

15. The rotating stage according to claim 14 , wherein the composite layers are provided by a matrix composite material, wherein the matrix composite material is integrated with the fibers.

16. The rotating stage according to claim 14 , wherein the fabric compliant wedge layer extends axially to an end face of the root, wherein the fabric compliant wedge layer has a tapered cross-section.

17. The rotating stage according to claim 14 , wherein the fabric compliant wedge layer is 50%-90% of theoretical density.

18. The rotating stage according to claim 17 , wherein the fabric compliant wedge layer has a compressive Young's modulus less than 75% of the uni-directional layer.

19. The rotating stage according to claim 18 , wherein the fabric compliant wedge layer has a compressive Young's modulus in the range of 25-50% of the uni-directional layer.

20. A component for a gas turbine engine comprising:

composite layers including uni-directional layers extending through the neck and the root, the uni-directional layers having adjacent surfaces spared apart circumferentially from one another by a wedge-shaped gap that extends from an apex to an innermost radial end of the root, and a fabric compliant wedge layer arranged in the gap and joining the adjacent surfaces of the uni-directional layers, the uni-directional layer and the fabric compliant wedge layer are integrated into a unitary matrix composite structure, wherein the matrix composite material is integrated with fibers, wherein uni-direction layers include the fibers extending in a generally first direction, and the fabric compliant wedge layer is uninterrupted in extending circumferentially at the innermost radial end to join the adjacent surfaces, the fabric compliant wedge layer includes a matrix composite material having the fibers extending in a second direction transverse to the first direction, the fabric compliant layer has an increased porosity compared to the uni-directional layers, the fabric compliant wedge layer is 50%-90% of theoretical density, wherein the fabric compliant wedge layer has a compressive Young's modulus less than 75% of the uni-directional layers.