Improved Life Remaining Predictions and Modeling for Propulsion Drive Train Bearings Using Photon Induced Positron Annihilation (PIPA)

"Propulsion jet engine and drive train components are critical to our forward deployed military aircraft. Key components within are the bearings designed to make dependable operations a reality. Currently, drive train bearing life is based uponmanufacturer projections which address a nominal group-life failure before replacement. However, drive train bearings in combat jet engines experience varying loads and suffer from unique operational conditions. Spalling fatigue damage in one of the morecommon failure mechanisms in drive train bearings. Spalling, caused by micro-plastic deformation, leads to subsurface cracking, flaking and eventual bearing failure. Due to advances in improved bearing materials many bearings have mission life remainingeven with detectable damage. This would potentially extend operational readiness and minimize platform downtime. A definitive understanding of the buildup of operational damage and remaining bearing life once a fault is identified is required. A newtechnology, PIPA, has demonstrated a capability to nondestructively characterize operational damage in metallic materials leading to accurate assessment of remaining useful life. This Phase I effort will investigate the feasibility of quantifying usablelife remaining in jet engine bearings provided in collaboration with a major DoD vendor, delivering new bearing prognostic models for the military and commercial aerospace industry. This technol