Pultruded FRP Beams with Embedded Fibre Bragg Grating Optical Sensors for Strain Measurement and Failure Detection.

Daniel Maldonado-Hurtado,Salvador Sales,Javier Madrigal,Rocío Ruiz,Antonio Penades,Ana Isabel Crespo

doi:10.3390/s21217019

Abstract

Composites have added new dimensions to the design and construction of buildings and structures. One of the wider spread composite applications in the construction industry is composite beams or pillars, which can be manufactured through pultrusion processes. These types of construction elements are usually used to withstand the weight of large loads, so their integrity must be guaranteed. Due to optical sensors’ advantages over their electrical counterparts—small sizes, low weight, non-conductive, and immunity to electromagnetic interference—and FBGs having an outstanding position among optical fibre sensors—due to their multiplexation capability and relatively easy monitoring—in this study, we propose the integration of FBG sensors for the observation and analysis of the integrity of structures made with composite beams over time. The validation test results showed the successful embedding integration of FBG-based fibre optical sensors in an FRP pultrusion beam and strain transmission up to 7500 µɛ from the composite test piece to the sensor. Additionally, we were able to anticipate the piece failure by the FBG spectrum deformation.

Highlights

Fibre-Reinforced Polymer (FRP) beams can be produced by several composite manufacturing processes (CMPs) other than pultrusion, such as autoclave, vacuum infusion, and resin transfer moulding (RTM)
If we compare all these processes, pultrusion is the unique continuous manufacturing process resulting in the steady output of a composite profile, which is cut to length at the end of the process
During the pultrusion process, roving continuous fibres are pulled through a resin bath where they become impregnated with resin and are later pulled through a heated die

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Composite materials are formed at macroscopic scale from the combination of two or more different materials. This allows the structural use of materials in forms with superior properties to the constituent elements. The difference between materials can be recognized as they do not dissolve or blend into each other

Methods

Results

Conclusion