Embedded Long Service Life Monitoring System for Aluminum Alloy Sensitization

The Navy is adopting more extensive use of aluminum to achieve the mission requirements of high-speed combatant and non-combatant vessels such as the Littoral Combat Ship (LCS) and Joint High Speed Vessel (JHSV). Although 5XXX series alloys have excellent marine corrosion resistance, sensitization can cause susceptibility to intergranular corrosion, exfoliation and stress corrosion cracking. Alloy sensitization can occur over time due to a combination of improper processing and elevated service temperatures. To maximize structural performance and minimize inspection demands, Luna proposes a robust monitoring system that will measure degree of sensitization (DoS) and physical property degradation of 5XXX series aluminum. Luna"s embedded monitoring system will merge complimentary measurements of ultrasonic attenuation and velocity with temperature and strain to determine DoS, mechanical properties, texture parameters, and plastic and elastic strain. The open architecture, autonomous system will provide accurate and reliable information for improved monitoring and damage state awareness. Luna will leverage its ultrasonic inspection instrumentation for residual stress, fatigue and weld characterization, as well as Luna"s smart wireless sensor systems for health monitoring of Navy ships and aircraft. The system will be compatible with Navy maintenance networks systems such as ICAS. These wireless network devices can be powered by energy harvesting.