Methods to effectively and reliably embed the optical fiber sensors in the composite material have been investigated in this work with particular regard to a sailing boat mast manufacturing process by means of bagging technique in autoclave. At first, small samples were produce in order to investigate the effect of the curing process parameters on the light transmission characteristics of the embedded optical fibers. Polyamide and acrylate coated optical fibers were tested measuring the relative coefficient of attenuation by an Optical Time Domain Reflectometer. Carbon fiber reinforced epoxy laminas with embedded FOBGs were then manufactured and specimens for tension tests were extracted from the laminas. Each specimen had a centrally positioned FOBG in the specimen mid-plane and a conventional electrical strain gage (eS/G) adhesively bonded on its surface. The comparison between the FOBG and eS/G measurements, recorded during static and dynamic tensile tests, permitted to assess the strain monitoring capability of the FOBGs and assess their sensitivity and accuracy. The integration of a FOBG system into an advanced composite structure is a crucial issue for the development of a realtime monitoring system integrated into a composite sailing boat mast, able to detect in-service strain and prevent failure. KEYWORDS Composite materials, Fiber Optic Bragg Gratings (FOBG), Mechanical behavior, Nautical sector
Strain monitoring in advanced composite structures for nautical applications
DI SANTE, RAFFAELLA;DONATI, LORENZO;TROIANI, ENRICO;PROLI, PAOLO
2012
Abstract
Methods to effectively and reliably embed the optical fiber sensors in the composite material have been investigated in this work with particular regard to a sailing boat mast manufacturing process by means of bagging technique in autoclave. At first, small samples were produce in order to investigate the effect of the curing process parameters on the light transmission characteristics of the embedded optical fibers. Polyamide and acrylate coated optical fibers were tested measuring the relative coefficient of attenuation by an Optical Time Domain Reflectometer. Carbon fiber reinforced epoxy laminas with embedded FOBGs were then manufactured and specimens for tension tests were extracted from the laminas. Each specimen had a centrally positioned FOBG in the specimen mid-plane and a conventional electrical strain gage (eS/G) adhesively bonded on its surface. The comparison between the FOBG and eS/G measurements, recorded during static and dynamic tensile tests, permitted to assess the strain monitoring capability of the FOBGs and assess their sensitivity and accuracy. The integration of a FOBG system into an advanced composite structure is a crucial issue for the development of a realtime monitoring system integrated into a composite sailing boat mast, able to detect in-service strain and prevent failure. KEYWORDS Composite materials, Fiber Optic Bragg Gratings (FOBG), Mechanical behavior, Nautical sectorI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
