Shielding pockets for case holes

1. A case for a gas turbine engine, the case comprising:

a wall defining a through-hole, the wall configured with a base and a boss projecting out from the base, and the through-hole extending through the boss; and

first and second pockets adjacent to, and on opposite sides, of the through-hole;

wherein at least one of the first pocket or the second pocket includes a circular periphery;

wherein the wall extends axially along and circumferentially around an axis;

wherein the boss axially and circumferentially overlaps a first portion of the first pocket such that the boss is axially and circumferentially aligned with the first portion of the first pocket relative to the axis; and

wherein the boss is circumferentially adjacent a second portion of the first pocket.

2. The case as recited in claim 1 , wherein the first and the second pockets circumferentially flank the through-hole.

3. The case as recited in claim 1 , wherein at least one of the first or the second pockets each extends a depth from an inner surface of between 10%-50% of a thickness of the wall.

4. The case as recited in claim 1 , wherein a diameter of at least one of the first pocket or the second pocket is 100%-500% a diameter of the through-hole.

5. The case as recited in claim 1 , wherein an outer periphery of at least one of the first or the second pockets is circumferentially spaced a distance from an outer diameter of the through-hole along a hoop line, and the distance is between 10%-100% the diameter of the through-hole.

6. The case as recited in claim 1 , wherein

at least the first pocket or the second pocket extends for a depth from an inner surface between 10%-50% a thickness of the wall and has a diameter of 100%-500% of a diameter of the through-hole; and

the at least the first pocket or the second pocket has an outer edge circumferentially spaced a distance from an outer edge of the through-hole along a hoop line, and the distance is between 10%-100% of the diameter of the through-hole.

7. The case as recited in claim 1 , wherein the wall is an outer wall of a diffuser case.

8. The case of claim 1 , wherein the boss does not circumferentially overlap the second portion of the first pocket.

9. The case of claim 1 , wherein the boss and the first pocket are disposed on opposing sides of the base.

10. The case of claim 1 , wherein the boss has a circular outer peripheral edge.

11. A method of reducing stress in a case of a gas turbine engine, comprising:

reducing stress about a through-hole by providing a first concavity and a second concavity on opposing sides of the through-hole;

wherein the case extends axially along and circumferentially around an axis;

wherein the case includes a boss that projects out from a first side surface of the case, and the through-hole extends through the boss;

wherein the first concavity extends into the case from a second side surface of the case that is opposite the first side surface of the case; and

wherein the first concavity is configured with a circular periphery that partially circumferentially and axially overlaps the boss relative to the axis such that the circular periphery is axially and circumferentially aligned with the boss relative to the axis.

12. The method as recited in claim 11 , further comprising defining each of the first concavity and the second concavity in an inner surface of a wall, wherein the second side surface of the case is the inner surface of the wall.

13. The method as recited in claim 11 , further comprising defining each of the first concavity and the second concavity for a depth from an inner surface of the case between 10%-50% of a thickness of the wall.

14. The method as recited in claim 11 , further comprising defining each of the first concavity and the second concavity with an outer edge having a diameter of between 100%-500% of a diameter of the through-hole.

15. The method as recited in claim 11 , further comprising circumferentially spacing each of the first concavity and the second concavity a distance along a hoop line from between 10%-100% of a diameter of the through-hole.

16. A gas turbine engine assembly, comprising:

a case comprising a wall configured with a boss, a through-hole, a first pocket and a second pocket;

the wall extending axially along and circumferentially around an axis of the case;

the through-hole extending through the boss;

the first pocket and the second pocket arranged adjacent to and on opposing circumferential sides of the through-hole;

the wall comprising a first concave surface that forms the first pocket; and

a portion of the first concave surface axially and circumferentially overlapped by the boss such that the boss is axially and circumferentially aligned with the portion of the first concave surface relative to the axis.

17. The gas turbine engine assembly of claim 16 , wherein the first pocket is configured with a circular periphery.

18. The gas turbine engine assembly of claim 16 , wherein the first through-hole, the first pocket and the second pocket are arranged along a hoop line.

19. The gas turbine engine assembly of claim 16 , wherein a center of the through-hole is axially offset from a center of the first pocket along the axis.

20. The gas turbine engine of claim 16 , wherein

the wall further comprises a second concave surface that forms the second pocket; and

the second concave surface extends along a continuously curved line as the second concave surface extends between opposing edges of the second pocket when viewed in a plane parallel to the centerline of the first through-hole.