Barrel nut with stress reduction features

A method of reducing stress in a barrel nut comprising:

• forming a partial-cylindrical body having a first planar end surface and a second planar end surface;
• forming a threaded bore through the partial-cylindrical body with a central axis substantially parallel to the first planar end surface and the second planar end surface;
• and
• forming at least one groove in each of the first planar end surface and the second planar end surface extending at least a part of a distance between a curved upper surface of the partial-cylindrical body and a bottom surface of the partial-cylindrical body in a direction substantially parallel to the central axis of the threaded bore.

A method of mounting an aircraft engine to an aircraft, comprising the steps of:

• inserting a barrel nut into a cylindrical bore extending through an aircraft engine mount, the barrel nut comprising a partial-cylindrical body having a first planar end surface and a second planar end surface, a threaded bore extending through the partial-cylindrical body and at least one groove in each of the first planar end surface and the second planar end surface extending at least a part of a distance between a curved upper surface of the partial-cylindrical body and a bottom surface of the partial-cylindrical body in a direction substantially parallel to a central axis of the threaded bore;
• aligning the barrel nut within the cylindrical bore with bolt holes positioned through a top surface of the aircraft engine mount;
• and
• inserting bolts through the bolt holes and into the threaded bore in the barrel nut and tightening the bolts to a desired preload.