Development of a Distributed Direct Current Sensor System for Intelligent Resin Transfer Molding

Resin transfer molding (RTM) and other liquid molding techniques hold the promise of affordable manufacturing for a variety of critical Army applications including the Composite Armored Vehicle (CAV) and Comanche helicopter. A critical barrier to the development of a quality control system and to our ability to consistently manufacture quality parts using RTM is the availability of an integration-friendly and cost-friendly flow and cure sensing system. SMARTweave is an ARL-patented system for sensing the existence and state of cure of resin in RTM. The process uses a grid of conductive filaments laid within an RTM mold. As resin fills the mold, gaps between transverse filaments at the flow front are bridged by resin, and an electrical circuit is closed providing a signal that the flow front has reached that node. SMARTweave provides researchers and manufacturers with a sensing system that can be placed into an RTM mold and provide low-cost, real time information about the resin location and state of cure. This information is useful to validate and refine flow and cure models and to study flow and cure for various RTM techniques and materials, providing insight on the role of a complex system of variables that include viscosity, mold temperature, resin inlet temperature, mold design, port and vent locations, pressure, preform architecture and permeability, preform placement techniques, etc. Prepared in cooperation with University of Delaware.