To support development at NASA’s Stennis Space Center (SSC) testing facilities and infrastructure for the monitoring of remote or inaccessible measurement locations, American GNC Corporation (AGNC) and Rensselaer Polytechnic Institute (RPI) have developed the Through Wall Wireless Intelligent Sensor and Health Monitoring (TWall-ISHM) System. This technology allows deploying flexible instrumentation and health monitoring capability in fully enclosed areas such as vacuum jacketed pipelines or pressurized tanks by a non-intrusive data and energy transfer through-wall system where perforations are avoided, maintaining structural integrity of monitored systems. Major innovations and capabilities are: (a) non-intrusive sensing where holes in isolating walls are not required; (b) wireless data and power transmission through solid walls by robust ultrasound techniques; (c) self-diagnostics of piezoelectric (PZT) elements used either for ultrasound communications or as sensors; (d) embedded intelligent algorithms in the TIMs (Transducer Interface Modules), i.e. smart sensors; and (e) sensor network operation capability, i.e. smart sensors on both sides of the wall and in remote locations can communicate to a network coordinator. TWall-ISHM is an integral solution with Instrumentation and Measurement methods, advanced ultrasound communications (in addition to RF and wired communication), and health monitoring in an innovative yet practical product.
The TWall-ISHM will directly support NASA testing facilities by providing an innovative cost-effective instrumentation and measurement (I&M) as well as health monitoring system with minimally intrusive ultrasound communication and intelligent data analysis diagnostic techniques. The innovation of the system is the ability to extend measurement capabilities in previously inaccessible spaces where physical holes would either comprise structural integrity or result in major disassembly downtime costs. Potential applications are: (a) long-duration use in vacuum jacketed pipelines; (b) cryogenic systems monitoring; (c) explosive environments such as propulsion systems in test stands; (d) pressurized tanks and storage vessels; (e) strain gage instrumentation, (f) distribution systems, etc. Generally, the system can be used for expanding I&M in critical systems and test stands such as those at Stennis Space Center. Rather than requiring manual inspections over miles of pipelines, TWall-ISHM nodes (internal sensor system and outside data acquisition system) can be installed at specific locations for automatic data recovery. High-dollar value systems are a focus, where the TWall-ISHM should provide cost-savings by enabling flexible system monitoring without disassembling or drilling holes to obtain data and to analyze problems. The technology can be readily applied to different structure types, thus maximizing flexibility and ease of installation, further reducing costs for NASA.
The TWall-ISHM provides novel instrumentation and monitoring capability with significant application potential for a wide range of non-NASA systems within both civilian and military sectors. For example, the TWall-ISHM can be applied to systems health monitoring (processing of strain, stress, humidity, temperature, etc.) of equipment, machinery, and assets in difficult to reach locations such as airframe components (wings or enclosed fuselage compartments) and remote/inaccessible bridge elements, civil structures, and military systems. Innovative aerospace instrumentation and advanced measurement techniques will be enabled when considering data and energy transfer in pressurized aircraft cabins or cockpits, where sensors in both the outside and inside of the cabin can transmit data and power with the thru-wall ultrasound technology. Other applications are: (1) oil wells; (2) submarine hull data acquisition; (3) shipment containers monitoring (e.g. ultrasound tags instead of RFID tags); (4) underwater vehicles; (5) extending the coverage of existing wireless sensor networks (WSNs); (6) corrosion monitoring of civil structures, vessels, military infrastructure; (7) tracking of military assets and life-cycle status monitoring; (8) Computerized Maintenance Management Systems (CMMS) and Enterprise asset management; (9) complex system maintenance and repair guidance; (10) logistics and depot maintenance; and (11) Internet of Things (IOT).