Fringing Capacitive Array Sensor for Evaluation of Fiber Coatings

To address the U.S. Navy need for technologies/methods of low-cost, rapid nondestructive evaluation (NDE) of fiber coatings for ceramic matrix composites (CMCs), Physical Optics Corporation (POC) proposes to develop a new Fringing Capacitive Array Sensor (FCAS) system. The system is based on recent advances in fringing field sensors (FFSs) and a parameter estimation algorithm for NDE of materials. The innovative and unique structure of the multiwavelength FFS array will enable the FCAS system to rapidly (<5 minutes) evaluate large areas (scalable to specific needs, with a large number of sensor elements) of fiber coatings in one scan. In Phase I POC will demonstrate the feasibility of FCAS by designing a system prototype with 576 electrodes covering three wavelengths (for each wavelength, there is a 4x4 sensor array; each sensor element has six drive and six receive electrodes) and testing it on CMCs with fiber coatings from a CMC fabricator. In Phase II we plan to improve the FCAS system by optimizing the sensor, electronics, and data processing algorithm. We will quantify the measurement results, demonstrate this technique in a commercial fiber coating setting, and characterize coated fiber/fabric/perform samples.