Determination of the strain distribution in adhesive joints using Fiber Bragg Grating (FBG)

Abstract

This work focuses on the development and testing of a technique used to measure strain levels inside an adhesive joint. As more industries adopt high performance structural adhesives, the need for structural monitoring and quality control of adhesive joints rises. The method presented in this work, based on optic fibers, is proposed as a possible means for real-time health monitoring of adhesive connections. In the first part of this work a procedure for embedding optical fibers etched with Bragg sensors is explained. Instrumented, single lap joints were fabricated and subjected to tensile test. The results were compared with finite element models to ensure the accuracy and provide a better understanding of the measurement process.

Keywords:

• fiber Bragg grating
• adhesive joints
• single lap joint
• strain distribution

Acknowledgments

Fiber Bragg grating sensors were kindly supplied by FiberSensing, Portugal. Dr. P Moreira acknowledges POPH (Programa Operacional Potencial Humano) and QREN (Quadro de Referência Estratégico Nacional) – Tipologia 4.2 promotion of scientific employment funded by the ESF (European Social Fund) and MCTES (Ministério da Ciência, Tecnologia e Ensino Superior).