In this seminar I will present recent developments towards optical fiber
sensors and sensor networks that can be integrated into composite structures
for real time structural health monitoring. Embedded sensor networks are ideal
for applications such as composite aircraft components or satellites where
damage cannot always be inspected during the service of the component.
Optical fiber sensor networks provide the ability to multiplex a large number
of sensors with minimal ingress to and egress from the structure and require no
electrical current running through the network. Additionally, as will be
emphasized in this presentation, the capability to multiplex multiple sensor
physical scales permits damage identification at much higher accuracies than
other sensing strategies. Current work at NCSU has focused on the optical
sensor design, their embedment during the fabrication of composite materials
and the design of sensor networks.
In particular, this presentation will focus on recent achievements in optical
fiber sensor network technology: (1) the development of intrinsic, single-mode polymer
optical fiber sensors that can sustain large deformations and are therefore
suitable for highly flexible structures; (2) the integration of multi-scale
fiber Bragg grating sensor networks into woven composite laminates to monitor
the formation and growth of damage due to multiple impact loads; and (3)
numerical modeling of state-of-the-art micro-optical devices such as microstructured and photonic bandgap
optical fibers for future micro-sensors. Additional applications such as
the integration of sensors into fiber reinforced polymer strengthening for
civil infrastructure applications and polymer cure testing for VARTM processing
of large structural components will be briefly presented. Finally, future
research directions will be outlined, focusing on sensor networks with low size
and power requirements such that they can be embedded into composite materials
at high densities without damaging the integrity of the composite material and
operate with wireless based systems.
This work has been funded by the NSF, NASA, AFOSR, and ONR.