Landing Gear Fatigue Damage Detection and Tracking Using MWM-Arrays

ABSTRACT: The high-strength steels (HSS) used for landing gear components have a relatively low fracture toughness, and, therefore, once a crack is formed in a HSS component, it may grow rapidly, potentially leading to catastrophic failure of the part and potential loss of the aircraft. This SBIR program will demonstrate the capability of JENTEK Sensors'substantially improved MWM-Array flexible eddy current technology to detect early stage fatigue damage in high-strength steels used for landing gear. In Phase II, JENTEK will implement enhancements in the measurement and data processing procedures, scanning apparatus, and most importantly, a new GridStation instrument that is expected to dramatically improve early fatigue damage detection capability. Fatigue tests will be performed on HSS coupons and subcomponents to demonstrate the MWM-Array's capability to image fatigue damage associated permeability changes for HSS. Early fatigue damage identified by MWM-Array imaging will be verified using methods such as scanning electron microscopy and fractography. A scanning fixture will be adapted for MWM-Array imaging of a landing gear component to support demonstration on an actual landing gear component or representative subcomponent. Coupon and subcomponent tests will include selected features such as shot peening, coatings and geometric complexity to address specific Air Force needs. BENEFIT: Landing gear is a critical, non-redundant system in military and commercial aircraft. The capability to inspect for early fatigue damage with the MWM-Array technology is expected to enable reduction in inspection frequency, increased margins of operational safety, transitioning to a condition-based maintenance paradigm and the corresponding life extension of landing gear components. These benefits could be achieved on both military and commercial landing gear and any other application with high value HSS components. The technologies developed will be readily adaptable to rotorcraft, ship, and ground vehicle drive trains, and to ferrous steel elements in commercial aircraft and other critical structures. Because maintenance and support tasks account for the largest portion of total ownership costs, significant savings can be realized over the lifecycle of these systems with condition-based maintenance.