U.S. Army helicopter fatigue sensitive dynamic components are required to maintain structural integrity throughout their operational life cycle. Typical metal alloy fatigue sensitive dynamic components require the presence of surface compressive residual stresses to inhibit the initiation and propagation of fatigue cracks. However, some of these components are susceptible to localized mechanical and corrosion surface damage that must be removed by blending. The surface blending process results in the requirement to reintroduce compressive residual stresses, normally by shot peening. The shot peening operation is currently performed at military depots and commercial facilities using non-portable peening equipment. Army Aviation has the potential for increasing reliability, availability, and maintainability (RAM), while reducing Operation & Support (O&S) cost by deploying a portable capability to reliably restore the structural integrity of fatigue sensitive dynamic components that have experienced usage related surface defects. Avion (Prime) and Sonats (Sub) have teamed to demonstrate the feasibility of developing a portable, field-deployable Stressonic® shot peening capability that reliably reintroduces compressive residual stresses in Army helicopter fatigue sensitive dynamic components that have had localized surface damage blended out.
Keywords: Rotorcraft, Dynamic Component, Surface Damage, Blending, Residual Stress, X-Ray Diffraction, Fatigue Life, Ultrasonic Peening
