Description: This SBIR project delivers a single-sensor structural health-monitoring (SHM) system that uses the impedance method to monitor structural integrity, wave propagation methods to assess surfaces, and acoustic SHM to detect adverse events (impacts). This Adverse Event Detection (AED) unit supports nondestructive evaluation (NDE) systems and evaluates advanced composite structures. Implications of the innovation Increasingly demanding weight and performance needs encourage widespread use of composite materials. New systems are needed to detect incipient flaws in composites before damage becomes critical. Health analyzers that actively examine structures across several length and time scales in an autonomous fashion greatly reduce the number of sensors required and lower system complexity and cost; however, no practical system exists. We address this deficiency by building on our existing SHM system. Technical objectives AED leverages our previous NASA SHM research. Our initial Phase 1 prototype takes the form of a single custom printed circuit board, and is a TRL 5 unit. We have demonstrated both the impedance method and wave propagation SHM as implemented by a single sensor. Phase 1 will focus on performing similar demonstrations for acoustic SHM using the same single sensor element. Research description We have established feasibility for a chip-level approach that combines the impedance method and wave propagation, and demonstrated damage detection on a model composite. Phase 1 will validate chip-level feasibility for acoustic operation, and demonstrate this additional capability in a laboratory prototype. Anticipated results Phase 1 attacks the problem of monitoring structural integrity across multiple time and distance scales and completes a TRL 5 prototype that can be deployed wirelessly. Phase 2 delivers a TRL 6 unit that autonomously senses damage across several length and time scales by integrating impedance based, wave propagation, and acoustic SHM.

Benefits: Non-NASA commercial applications include Homeland Security structural analysis to mitigate threats (preparedness) and assess damage (response), smart structures, and SHM of civil infrastructures, land/marine structures, medical devices, and military structures. Civil infrastructure includes bridges, highway systems, buildings, power plants, underground structures, and windmills. Land/marine structures include automobiles, trains, submarines, ships, and offshore structures. Medical devices include implants and health monitoring devices. Military structures include helicopters, aircraft, unmanned aerial vehicles (UAV) and others. SHM is an emerging industry driven by an aging infrastructure, malicious humans, and the introduction of advanced materials and structures. SHM applications are also driven by a desire to lower costs by moving from schedule-based to condition-based maintenance. Government customers include NASA and the Departments of Defense, Transportation, and Energy. Non-government customers include energy companies, and other crucial-structure custodians. The Boeing Company is one of our civilian commercialization partners; we are also working with the United Space Alliance, Lockheed-Martin and Ball Aerospace.

AED directly supports NDE systems for safety assurance of future exploration vehiclesspecifically those making heavy use of composite materials. By provided increased reliability, AED also supports low-cost and reliable access to space (LCRATS). AED provides enabling technology for this effort. AED supports the NASA Engineering and Safety Center by providing tools for independent testing, analysis, and assessment of high-risk projects. AED applications include on-wing SHM of various aircraft components and is applicable to the next generation of turbine engines. These advanced propulsion systems will use revolutionary materials and structures. Structures based on such materials must withstand severe stresses and hostile aero-thermo-chemical environments, while weighing less and operating at higher temperatures than current engines. AED sensors are embeddable and are well suited to the highly curved surfaces found in pressure vessels and hard-to-access composite members of all sorts. AED detects incipient damage in near real-time and automatically provides early warning of structural damage. These capabilities are well suited to support of exploration missions where routine action may be taken to rectify damage situations before failure occurs.