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|Author:||Adam Benjamin Haskell|
|Title:||A Durability and Utility Analysis of EFPI Fiber Optic Strain Sensors Embedded in Composite Materials for Structural Health Monitoring|
|Committee Members:||Roberto Lopez-Anido, Ph.D., P.E., Associate Professor, Department of Civil and Environmental Engineering; Eric Landis, Ph.D., P.E., Associate Professor, Department of Civil and Environmental Engineering; William Davids, Ph.D., P.E., Associate Professor, Department of Civil and Environmental Engineering|
|Subjects:||Fiber optics; Optical fiber detectors|
|Date of Defense:||2006|
The objective of the research work was to develop a method to embed fiber optic sensors (FOS) that measure strain in polymer matrix composite (PMC) laminates and sandwich composite panels, to apply the technology to structural health monitoring, and to assess the durability of the sensor system through a fatigue test protocol applied to sandwich composite panels. There is a growing interest in determining and monitoring the performance and sustainability of structures such as bridges, buildings, marine vessels, and aerospace structures. By monitoring structural elements, damage to the structure can be detected resulting in more efficient repair and maintenance schedules, the life of the structure can be potentially prolonged, and design assumptions can be refined with a better understanding of the loading and performance of the structure. The goal of the structural health monitoring of the Advanced Engineered Wood Composites (AEWC) Center office building expansion was to develop a system of fiber optic strain sensors embedded in PMC laminates and combination temperature and relative humidity sensors to monitor the effect of changes in the building’s environment and loading conditions on the performance of structural elements. A method to embed FOS in sandwich composite panels fabricated by the Vacuum Assisted Resin Transfer Molding (VARTM) method with Seemans Composite Resin Infusion Molding Process (SCRIMP) technology was developed for the fabrication of both PMC laminates and sandwich composite panels. The durability of the FOS was assessed throughout the fabrication process, the handling and installation of FOS PMC laminates on beams within the AEWC office expansion, and during fatigue testing of the sandwich composite panels. The sensor laminates proved to be durable throughout the fabrication and installation process and have provided reasonable results which reflect expected loading conditions. A fatigue test program was developed to determine the performance of FOS embedded within the tension side face sheet of sandwich composite panels subject to cyclic loading utilizing the hydromat test system. The embedded fiber optic strain sensors proved to be durable as all sensors survived the duration of the fatigue cycling including failure of the sandwich composite panel. The FOS embedded in the sandwich composite panels constructed with carbon fiber face sheets exhibited a better performance than panels constructed with E-glass face sheets and correlated relatively well with multiple panels tested and with strain values obtained from a 3-D digital image correlation system.
Haskell, Adam Benjamin, University of Maine, CIE2006-004