The primary NASA application focus for the Metal Rubber extensometers developed through this STTR program is the nondestructive measurement of creep in woven fabric webbings used to control and maintain the shape of space habitats. Monitoring long-term creep allows the statistical estimation of the remaining lifetime of the webbing material, and it is important that this estimate be significantly longer than the required mission lifetime of the inflatable. NanoSonic's Metal Rubber material may be formed into either sheet materials that may be dimensioned into discrete creep extensometers, or into yarn that may be directly woven into webbings during their manufacturing. For NASA, discrete creep extensometers may be applied where needed on existing habitat webbing, or built into the webbings during habitat production. Other similar NASA applications that require the measurement of strains without interfering with the performance of devices include use in 1) landing airbags such as those used on Mars rover landings, 2) atmospheric decelerators such as HIAD and SIAD, 3) high altitude atmospheric research balloons used on earth and elsewhere, 4) high altitude airships, 5) EVA space suit and glove fabrics and bladders, 6) inflatable UAVs, and 7) aerostats. In all of these cases, the measurement resolution at small strains is important. Such sensors could also be used in e-textiles to monitor astronaut motions during operations and exercise.
The developed piezoresistive sheet and yarn extensometers may also be used for measurement of the strain, creep, shape and load on non-NASA inflatable structures including 1) commercial EVA space suits such as the recently demonstrated StatEx suit manufactured by our ILC Dover partner, 2) passenger airships that display messages at sporting events, 3) heavy-lift lighter-than-air vehicles used for military transport to remote regions supported by little infrastructure, 4) inflatable devices such as ILC Dover's tunnel plug used for New York City subway flood protection, 5) military aerostats, and 6) inflatable military or hobby UAVs. Additional uses include: motion-sensing fabrics, the development, testing and use of military and commercial round, cruciform, ribbon and ram-air parachutes, the design and testing of fabrics for custom clothing, measurement of extension in large civil structures and installations, such as the large strains due to subsidence in soil and rock formations and the long-term displacements of buildings, dams, roadways and pipelines, and in sensor-instrumented webbings used for climbing, load securing, sporting goods and healthcare products.
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