TDR-LINE SENSOR FOR MULTIFUNCTIONAL AND DISTRIBUTED SENSING IN LCM

摘要

Automated composite processes rely on feedback from embedded and tool-mounted sensors. Liquid composite molding (LCM) requires sensors for flow and cure monitoring. Most current sensors are point sensors that monitor DC or AC response at discrete locations. A large array of point sensors is required for lull spatial resolution. The current study has developed a novel lineal sensor based on Time-Domain-Reflectometry (TDR). The TDR-Line sensor is capable of providing distributed sensing of several process parameters such as flow, cure and potentially strain. E-TDR is a method of sending a high-speed pulse down a controlled-impedance transmission line, and detecting reflections returning from impedance discontinuities within the line. Time scales are extremely fast, so the reflections occurring at different positions in the line are separated by time-of-flight of the electromagnetic pulse. The TDR-Line sensor provides high-resolution information (resolution of approximately 3mm) of the resin flow front location during resin injection when the sensor is placed along the flow direction. The sensor has the unique features to locate multiple flow fronts during resin infusion and to monitor accurately the cure behavior over time. The paper highlights the multi functional capability of the sensor to detect flow and cure simultaneously compared to conventional point sensors.