| 摘要 |
A method of coldworking a hole through a work piece which includes placing a seamless tubular member within the hole with a prescribed hoop strength to allow the tubular member to be expanded and prescribed column strength which prevents axial movement of the outside of the tubular member as the tubular member is expanded, holding the tubular member within the hole so that the tubular member is substantially axially fixed with respect to the hole, and passing an expansion mandrel through the inside of the seamless tubular member to radially and circumferentially expand the tubular member sufficiently to induce a compressive stress gradient of a prescribed magnitude in the material of the work piece substantially uniformly about the entire inside surface of the hole so as to increase the fatigue strength thereof. The application also discloses a method of isolating the fastener bearing interface from the inside surface of the hole of the work piece to isolate the fretting phenomenom associated with the bearing interface at the fastener from the work piece.
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