2010 R&D 100 Winner
Carefully applied, compressive stress can improve the impact resistance and fatigue life of metallic components. In airplane wings and other structures, techniques such as shot peening and laser shocking are used, but drawbacks with these methods include high cost, cold working time, and component damage. Low Plasticity Burnishing (LPB), a new technology from NASA Glenn Research Center, Cleveland, Ohio, and Lambda Technologies, Cincinnati, Ohio, offers residual stress orders of magnitude deeper than shot peening with minimal plastic deformation.
LPB produces a layer of compressive stress of high magnitude and depth, with minimal plastic deformation or cold work. A single pass of a smooth, free-rolling spherical ball under a normal force deforms the surface of the material in tension, creating a compressive layer of residual stress. The ball is supported in a fluid with sufficient pressure to lift the ball off the surface of the retaining spherical socket, which means it is in mechanical contact only with the surface of the material being burnished. This allows the ball to roll freely on the surface, and for exact control of the force being applied. The approach also extends tool life and eliminates the possibility of dragging the ball and damaging the surface.
Technology
Metal-strengthening process
Developers
NASA Glenn Research Center
Lambda Technologies
Honeywell Engine Systems
Development Team
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| Timothy P. Gabb and Ignacy (Jack) Telesman, NASA Glenn Research Center |
The Low Plasticity Burnishing Development Team:
Tim Gabb, NASA Glenn Research Center
Doug Hornbach, Lambda Technologies
Pete Kantzos, Honeywell Engine Systems
Perry Mason, Lambda Technologies
Paul Prevey, Lambda Technologies
Ignacy (Jack) Telesman, NASA Glenn Research Center
