Additive manufacturing process grown integrated torsional damper mechanism in gas turbine engine blade

1. A blade for a gas turbine engine comprising:

an airfoil portion configured with a tip, a leading edge, a trailing edge, a concave pressure sidewall, a convex suction sidewall and at least one internal cavity formed by and extending laterally between the concave pressure sidewall and the convex section sidewall, the airfoil portion extending spanwise to the tip, and the airfoil portion extending longitudinally from the leading edge to the trailing edge; and

a damper located within the internal cavity, the damper including a friction bridge, a rub surface pad, a cantilever spring arm and a base that extends across the cavity from the concave pressure sidewall to the convex suction sidewall, the cantilever spring arm projecting longitudinally out from the base towards the leading edge or the trailing edge and to the rub surface pad, the rub surface pad located within the cavity adjacent the friction bridge, and the friction bridge extending laterally across the cavity between and connected to the concave pressure sidewall and the convex suction sidewall.

2. The blade as recited in claim 1 , wherein the airfoil portion extends from a platform portion of a fan blade.

3. The airfoil as recited in claim 1 , wherein the cantilever spring arm terminates with the rub surface pad.

4. The blade as recited in claim 1 , wherein the damper further includes a motion limit bridge extending laterally across the cavity between and connected to the concave pressure sidewall and the convex suction sidewall, and the rub surface pad is located spanwise between the friction bridge and the motion limit bridge.

5. The blade as recited in claim 1 , further comprising a clip removable mounted to at least one of the rub surface pad and the friction bridge.

6. The blade as recited in claim 1 , further comprising a clip additively manufactured to the friction bridge, the clip additively manufactured of a material different than the friction bridge.

7. The blade as recited in claim 1 , further comprising a clip additively manufactured to the rub surface pad, the clip additively manufactured of a material different than the rub surface pad.

8. The blade of claim 1 , wherein the friction bridge is located spanwise between the rub surface pad and the tip.

9. The blade of claim 1 , wherein the rub surface pad is configured to engage the friction bridge in a spanwise direction.

10. The blade of claim 1 , wherein

the base is longitudinally separated from the airfoil portion at the leading edge by at least a first longitudinal gap; and

the base is longitudinally separated from the airfoil portion at the trailing edge by at least a second longitudinal gap.

11. The blade of claim 1 , further comprising:

a second damper including a second friction bridge, a second rub surface pad, a second cantilever spring arm and a second base;

the second base extending from the concave pressure sidewall to the convex suction sidewall;

the second cantilever spring arm projecting longitudinally out from the second base towards the trailing edge and to the second rub surface pad, wherein the cantilever spring arm projects longitudinally out from the base towards the leading edge;

the second rub surface pad located adjacent the second friction bridge; and

the second friction bridge extending laterally between and connected to the concave pressure sidewall and the convex suction sidewall.

12. A fan blade for a gas turbine engine, comprising:

an airfoil portion configured with a tip, a leading edge, a trailing edge, a concave pressure sidewall, a convex suction sidewall and at least one internal cavity formed by and extending laterally between the concave pressure sidewall and the convex section sidewall, the airfoil portion extending spanwise to the tip, and the airfoil portion extending longitudinally from the leading edge to the trailing edge; and

a damper located within the internal cavity, the damper including a cantilever spring arm that terminates with a rub surface pad spanwise adjacent to a friction bridge that extends across the cavity from the concave pressure sidewall to the convex suction sidewall, wherein the rub surface pad is configured to engage the friction bridge in a spanwise direction.

13. The fan blade as recited in claim 12 , wherein the cantilever spring arm extends from a base that extends between and is connected to the concave pressure sidewall and the convex suction sidewall.

14. The fan blade as recited in claim 12 , wherein the rub surface pad is located spanwise between the friction bridge and a motion limit bridge between the concave pressure sidewall and the convex suction sidewall.

15. A method of damping a blade of a gas turbine engine, the method comprising:

deflecting a cantilever spring arm in a spanwise direction towards a tip of the blade to contact a rub surface pad with a friction bridge that extends, across a cavity in an airfoil portion of the blade, from a concave pressure sidewall to a convex suction sidewall of the airfoil portion of the blade such that the friction bridge is connected to the concave pressure sidewall and the convex suction sidewall.

16. The method as recited in claim 15 , further comprising deflecting the cantilever spring arm under a centrifugal load generated by rotation of the blade.

17. The method as recited in claim 16 , wherein the centrifugal load generated by rotation of the blade is on the order of about thirty and about sixty thousand Gs.

18. The method as recited in claim 16 , wherein the rub surface pad and the friction bridge include a fretting surface coating.

19. The method as recited in claim 15 , further comprising additively manufacturing the concave pressure sidewall and the convex suction sidewall.

20. The method as recited in claim 19 , further comprising additively manufacturing the cantilever spring arm and the friction bridge with the concave pressure sidewall and the convex suction sidewall.