Laser Peening for Army Vehicle Life Extension

The U.S. Army is evaluating laser peening technology in support of major helicopter programs, including the AH-64 Apache, UH-60 Black Hawk, and CH-47 Chinook fleets. The Army has a critical need to boost the engine horsepower for these helicopters, especially when operating in high altitude theaters such as Iraq and Afghanistan. Laser peening offers a method of increasing the fatigue performance and damage tolerance of these components without increasing the size or the weight of the propulsion system. Laser shock peening has been demonstrated to significantly increase the fatigue life of metallic components by the introduction of deep compressive residual stresses. The U.S. Army utilizes numerous fatigue-critical components, which potentially could be improved by laser peening. The overall objective of the work proposed in this SBIR II program is to develop, optimize, and demonstrate laser peening technology specifically for rotorcraft materials and components, such as carburized steels for gear applications. The results from the Phase I program and the LSPT’s subsequent work with bend fatigue tests and component tests indicate that a very significant benefit from laser peening can be achieved when laser peening gears, and is driving the extension of this work to advanced rotorcraft gear steels.