Wireless Sensing for In-Situ Impact and Damage Location in Anisotropic Aerospace Structures

The ability to quickly and inexpensively detect and identify incipient damage in aerospace structural components before catastrophic failure occurs has become a pressing need for the Air Force. Acoustic emission technologies have been explored extensively over the last 30 years for NDE and structural health monitoring applications, but significant limitations exist in practically implementing this technology due to the difficulty in damage location for composite and built-up structures, the relatively bulky acoustic emission sensors, and the extensive wiring required for the system. NextGen Aeronautics in collaboration with the University of Arizona are proposing to develop robust damage location algorithms and a very low power wireless AE sensor which will overcome the current limitations in AE system technology. The proposed AE sensor network will be capable of locating damage in composite and built-up structures without prior characterization of the structure by initially actively interrogating the structure, the system then switches to a passive listening mode which continuously monitors the structure, but requires very little power. This approach will allow the user to place the wireless sensor system as desired with little effort, maximizing the utility of the system and reducing installation costs. We will improve and optimize algorithms that have been developed previously by Dr. Kundu at the University of Arizona for impact location in composite plates using AE signals. The proposed sensor node will integrate the rapidly developing area of wireless communications, and integrated circuit technology, with smart materials technology to perform continuous monitoring of the vehicle structures. The objective of the Phase I program is to develop and demonstrate that the proposed damage locator algorithms and conceptually design the low power wireless sensor node. In order to achieve this goal, the proposed algorithms will be experimentally tested on a variety of metallic and composite specimens and a breadboard level prototype of the wireless AE sensor will be developed.  We will achieve a TRL of 3 in Phase I and subsequent technology transition to a TRL of 5 in Phase II. NextGens strength lies in related prior work, comprehensive knowledge of damage detection techniques, as well as an established history transferring R&D efforts into higher technology readiness levels (TRLs) for integration onto military platforms BENEFIT: The proposed technology has the potential to significantly reduce the life-cycle cost of new aerospace structures by allowing condition based maintenance. The proposed damage location algorithms and wireless acoustic emission sensors will make a practical SHM system feasible which will help reduce the repair time by detecting impacts and damage at an early stage, thereby increasing overall system readiness and increasing probabilities of mission success. In addition to aerospace applications, other commercial applications of this technology include monitoring of pressure vessels, storage tanks, piping, nuclear power plants, Naval surface ships and submarines and other critical engineering structures)