COMPOSITE STRUCTURE RESIN CURE MONITORING USING AN OPTICAL FIBER GRATING SENSOR

摘要

Resin curing of a composite laminated structure is monitored using an optical fiber (20) having a grating sensor (28) embedded therein. The fiber (20) is surrounded by upper and lower buffer regions (12, 14) having a predetermined minimum number of layers (30) (or thickness) with uni-directional reinforcing filaments (32) and resin (34) therebetween. When the filaments (32) are oriented perpendicular to the longitudinal axis of the fiber (20), the buffer regions (12, 14) allow the sensor (28) to exhibit maximum sensitivity to detection of the minimum resin viscosity and the gelation point (i.e., the onset of a rapid cross-linking rate) of the resin (34). The buffer regions (12, 14) also have a minimum thickness which serves to isolate the sensor (28) from interfering stresses from arbitrarily angled filaments (32) in layers (30) of outer regions (10, 16) which surround the buffer regions (12, 14).