Method for release of fan blisk airfoil with external shaped charge

1. A method of releasing a fan blade for testing a turbofan engine, comprising:

modifying an airfoil by extricating material from one or more external sides of the airfoil at one or more locations;

placing one or more explosive charges adjacent the one or more locations;

providing with the one or more explosive charges a liner between the one or more explosive charges and the one or more external sides of the airfoil;

aligning the one or more explosive charges and the liner with the one or more cavities in the one or more sides of the airfoil; and

detonating the one or more explosive charges such that the airfoil is released at a selected time and the liner accelerates through a cavity provided by the one or more cavities.

2. The method of claim 1 , further comprising:

modifying the airfoil by extricating a first portion of material from a leading edge to provide a first cut out;

modifying the airfoil by extricating a second portion of material from a trailing edge to provide a second cut out; and

arranging one or more detonators in the first cut out or the second cut out.

3. The method of claim 2 , further comprising:

modifying the airfoil by extricating additional portions of material from one or more sides of the airfoil; and

aligning the one or more explosive charges with one or more cavities formed in the one or more sides of the airfoil by the extricating of the additional portions.

4. The method of claim 3 , further comprising:

selectively weakening the airfoil by extricating the additional portions of material from the one or more sides of the airfoil;

wherein, by aligning the one or more explosive charges and the liner with the one or more cavities in the one or more sides of the airfoil, the liner operates in combination with the selective weakening such that the airfoil is evenly released.

5. The method of claim 1 , wherein the liner cuts through the airfoil from an exterior of the airfoil toward an interior of the airfoil.

6. The method of claim 5 , wherein the liner cuts through the airfoil from both first and second sides of the one or more sides of the airfoil.

7. The method of claim 3 , further comprising:

arranging a first detonator holder in the first cut out;

arranging a second detonator holder in the second cut out; and

holding with the first and second detonator holders the one or more detonators.

8. The method of claim 7 , wherein the one or more explosive charges comprises an external shaped charge and further comprising:

holding the external shaped charge to first and second sides of the one or more sides of the airfoil with first and second charge holders;

the first and second detonator holders in combination with the first and second charge holders detonating the external shaped charge such that the airfoil is evenly released.

9. The method of claim 8 , further comprising:

detonating the external shaped charge from both the first and the second sides of the airfoil at both the leading edge and the trailing edge such that the airfoil is evenly released.

10. The method of claim 9 , further comprising:

controlling the detonating of the external shaped charge with a detonation controller that is operatively coupled to the one or more detonators.

11. The method of claim 9 , further comprising:

detonating the external shaped charge from both the first and second sides of the airfoil at both the leading edge and the trailing edge simultaneously.

12. An assembly for releasing a fan blade from a turbofan engine during testing, comprising:

an airfoil;

an external shaped charge arranged about the airfoil;

one or more detonators operatively coupled to the external shaped charge;

wherein the airfoil is modified to accommodate the external shaped charge; and

wherein the airfoil is modified to selectively weaken the airfoil; and

a liner arranged in a cavity along first and second sides of the airfoil, wherein the one or more detonators detonate the external shaped charge to cause the liner to cut the airfoil from an exterior of the airfoil toward an interior of the airfoil.

13. The assembly of claim 12 , further comprising:

first and second charge holders;

wherein the first charge holder is on the first side of the airfoil and the second charge holder is on the second side of the airfoil; and

wherein the cavity is formed by a combination of at least one of the first and second charge holders and modification of the airfoil by removing material at selected locations on the first and the second sides of the airfoil.

14. The assembly of claim 13 , further comprising:

a leading edge and a trailing edge of the airfoil; and

first and second cut outs;

wherein the first cut out is formed by modifying the leading edge of the airfoil; and

wherein the second cut out is formed by modifying the trailing edge of the airfoil.

15. The assembly of claim 14 , further comprising:

first and second detonator holders, wherein each of the first and the second detonator holders holds one or more detonators;

wherein the first detonator holder is disposed within the first cut out;

wherein the second detonator holder is disposed within the second cut out; and

wherein the one or more detonators held by each of the first and the second detonator holders is stimulated such that the external shaped charge on the first side and the second side of the airfoil is detonated to evenly release the airfoil.

16. A method of simulating a blisk fan blade off event, comprising:

arranging an external shaped charge about a fan blade;

wherein the external shaped charge is disposed radially outside of a blade platform and a blade root;

providing a liner between the external shaped charge and the fan blade; and

detonating the external shaped charge such that the liner accelerates into the fan blade and the fan blade is released; wherein the portion of the fan blade outside of the blade platform is released while the blade platform and the blade root are not released; and

wherein the portion of the fan blade released by the external shaped charge comprises at least a portion of a simulated blisk airfoil.

17. The method of claim 16 , further comprising:

modifying the fan blade to mount one or more detonator holders, one or more detonators, and one or more charge holders; and

modifying the fan blade to strategically weaken the fan blade such that the portion of the fan blade is evenly released.

18. The method of claim 17 , further comprising:

detonating the external shaped charge with more than one detonator;

detonating the external shape charge from more than one location along the external shaped charge; and

timing the detonation of the external shaped charge such the portion of the fan blade is evenly released.