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MAE PhD Defense – Tyler Hudson
October 25, 2017 @ 12:00 pm - 2:00 pm
TITLE: Real-time cure monitoring of composites using a guided wave-based system with high temperature piezoelectric transducers, fiber Bragg gratings, and phase-shifted fiber Bragg gratings. (Advisor: Dr. Yuan)
DATE: Wednesday, October 25, 2017
TIME & LOCATION: 12 PM EB3 – 3320
A guided wave-based, in-process, cure monitoring technique for carbon fiber reinforced polymer (CFRP) composites was investigated. Two cure monitoring systems using ultrasonic, guided wave-based measurements were developed. In the first system, high-temperature piezoelectric transducers were employed for actuation and sensing. In the second system, piezoelectric discs, bonded to the surface of the composite, were utilized for excitation and fiber Bragg gratings (FBGs) and/or phase-shifted fiber Bragg gratings (PS-FBGs) for sensing.
Composite material properties (viscosity and degree of cure) of the panels fabricated from Hexcel® IM7/8552 prepreg were correlated to the amplitude, time of arrival, and group velocity of the guided wave-based measurements. In addition, key phase transitions (gelation and vitrification) during the cure cycle were clearly identified from the experimental data. The material properties and phase transitions were validated using cure process modeling software.