Quantitative Gun Barrel Diagnostics with Eddy Current Techniques and Artificial Intelligence

ABSTRACT: The useful life of medium caliber gun barrels is dominated by fatigue cracking initiated early in the weapons’ deployment. Fatigue cracks worsen in severity throughout the life of the barrel until they reach a critical size, indicating end of life. During the Phase I effort, Luna demonstrated that eddy current (EC) techniques are effective in detecting both machined and fatigue-induced cracks inside gun barrels. EC-based measurements performed on several medium caliber barrels were not influenced by the intricate rifling profile of the bore of the barrel while remaining sensitive to cracks ranging from under 0.02 inches to greater than 0.375 inches. In the Phase II effort, Luna proposes development of an EC-based prototype with artificial intelligence post-processing algorithms for complete autonomy in assessing fatigue condition within barrels. A man-portable prototype for use on flight lines will be assembled, allowing for barrel evaluation without requiring their removal from the aircraft. Based on a multi-frequency excitation scheme, an improved design of the probes, and a trained neural classifier, the prototype will identify the number of existing cracks around the barrel circumference and assess their individual depths and locations.; BENEFIT: This project directly addresses the need for increasing savings and reducing maintenance cost of medium caliber gun barrels. Maintenance time and costs will be reduced by increasing barrel usage and reducing barrel replacement frequency. Currently, medium caliber gun barrels are retired when a maximum number of rounds is reached, often leading to premature removals. The developed system will allow for continued barrel usage throughout its entire useful life. The overall anticipated result of this effort is development of a new tool for assessing the condition of medium caliber gun inventory, replacing today’s statistically-based gun retirement protocol with a condition-based inventory management protocol. The proposed technology has broad market potential and meets a significant economic and national security need. Anticipated commercial uses include pipe inspection in the electric power, marine propulsion, and petrochemical industries.