Flexible Shear Stress Smart Skin for Submarine Applications

Physical Optics Corporation's (POC) objective is to develop a flexible MEMS-based shear stress sensor for Navy radio-controlled submarine model experiments. An array of transducers can enhance the flow characteristics of model hulls and control surfaces. POC proposes development of a novel waterproof shear stress transducer that can detect the direction and magnitude of shear stress under a water pressure environment with high spatial and temporal resolution. The device can assist with evaluating the hydrodynamic merit of new submarine designs. A robust stress transducer uses a floating element, coupled with fiber Bragg gratings (FBGs), which is deflected when exposed to fluid flow. A transducer uses Bragg gratings etched onto a symmetrical pair of fibers. A pair of FBGs balances deflection of the floating element, thereby reducing noise caused by the temperature/pressure effect. Gaps within the exposure surface of the floating element are covered by a silicon rubber thin film to resist water contamination. In Phase I, proof-of-concept will be demonstrated for waterproofing techniques on a MEMS-based transducer. A smart sensor network will be deisnged to address a large number of proposed devices to build a solid foundation for Phase II.