On-Aircraft Electrical Excitation for Damage Detection in Complex Structures

ABSTRACT:Structural issues in aircraft such as aging, fatigue, and cracking have significant effects on the reliability, safety, and lifetime of airframes. Historically managed through nondestructive evaluation (NDE) techniques, verification of airframe structural integrity has proven to be a costly and labor intensive process. Furthermore, NDE techniques often require removal of aircraft from service in order to perform the necessary analysis for crack detection and structural health verification. The ability to monitor for crack initiation and growth in-service throughout an aircrafts lifecycle will ensure early detection of impending faults while simultaneously supporting the Aircraft Structural Integrity Program (ASIP). To provide visibility into aircraft structural health, Luna proposes the development of an in-service, multi-modal sensing platform based on electrical impedance tomography and time domain reflectometry techniques to perform long-term evaluations of structural health including crack identification and quantification. The on-line, real-time measurements from an array of embedded electrodes will provide localization and quantification of structural defects while autonomously accounting for stochastic variability associated with complex aircraft structural components. The Phase I design will focus on demonstrating the feasibility of the measurement and analysis techniques, and will conclude with the development of a Phase II transition plan and a laboratory demonstration.BENEFIT:Development of the proposed system will offer aircraft maintainers a new, on-line method for evaluation of structural health without requiring significant aircraft down-time or labor intensive manual inspections. Using an array of measurement electrodes for electrical impedance tomography and time domain reflectometry, maintainers will be able to quickly identify, locate, and quantify damage within an airframe, allowing for adherence to damage tolerance concepts highlighted in the Air Forces Aircraft Structural Integrity Program. This project is a unique opportunity to combine technologies and expert knowledge in nondestructive evaluation, electronics, materials science, and structural health monitoring to establish a broadly applicable and comprehensive system for assessing in-service structural damage. Outside of the Air Force, civilian aerospace, transportation markets, infrastructure, and marine vessels can all benefit from the multi-modal impedance and reflectometry damage detection techniques.