The objective of this NASA STTR program is to develop conformal thin film sensors and sensor arrays for the direct measurement and mapping of distributed skin friction on the surfaces of flight-test vehicles and wind tunnel models at DFRC and other NASA centers. NanoSonic would use its patented Metal RubberTM
materials to fabricate the patterned "sensor skin" arrays. Metal RubberTM
is a free-standing self-assembled nanocomposite that acts as a transducer to convert shear stress into changes into electrical impedance. During this program, NanoSonic would work cooperatively with Virginia Tech to develop an improved mechanical and electrical model of skin friction sensor performance that will allow quantitative optimization of material properties and suggest optimal methods for sensor attachment and use for NASA applications. We will perform synthesis of sensor skin materials with optimized transduction, hysteresis and environmental properties, specifically for high Reynold's number flow and also varying temperature use. We will fabricate patterned two-dimensional sensor arrays and internal electronics using optimized materials. NanoSonic and Virginia Tech will perform complete analysis of sensor cross-sensitivities and noise sources to allow optimization of signal-to-noise ratio and practical sensor sensitivity. Support electronics will be developed to acquire, multiplex, store and process raw sensor array data. NanoSonic and Virginia Tech will also experimentally validate sensor array performance through extended water and wind tunnel evaluation, and possible flight testing, and produce a first-generation skin friction sensor array and data acquisition electronics system for sale.