<title>Processing monitoring of carbon/phenolic composites using smart sensors</title>

Abstract

It is well documented that high void content and delaminations are observed during the fabrication of thick carbon/phenolic composites due to the high percentage of volatile release that occurs during polymerization. In order to eliminate these imperfections and enhance product quality for thick carbon/phenolic composites, smart sensors are used to monitor the property changes during the processing and control of the component to minimize this effect. This paper documents an effort to develop a technique to monitor and collect sensor data during the curing process of a general material system. Data obtained from sensors are used to generate an expert processing knowledge base which automatically controls the composite cure state based on direct sensor response, in lieu of classical time/temperature techniques (i.e. recipes). Microdielectric, ultrasonic, thermopile, thermal couple, and Extrinsic Fabry-Perot Interferometer (EFPI) sensors are investigated as potential candidates to monitor and subsequently control the manufacturing process of a composite material. In addition to classical optical sensors, a modified EFPI thermal sensor is employed to monitor temperature variations.