Structural Analyses of GFRP with Embedded Fibre Optics Manufactured using Standard and Additive Manufacturing Methods

Abstract

This paper aims to analyse the structural differences between glass fibre reinforced polymer (GFRP) with embedded fibre optic sensors, in relation to the manufacturing method. Two methods were analysed: standard infusion and additive manufacturing (AM). For the AM method, a modified fused deposition modelling (FDM) technique was selected.

Structural analyses were performed using a Scanning Electron Microscopy (SEM) and a THz spectrometer. The results showed that the impact of embedded fibre optics on the internal structure of the composite depends on the manufacturing method. In the standard method, the embedded fibres are surrounded by a larger amount of polymer (referred to as a ”resin pocket”), while in the AM structure, part of the next 3D-printed layer shifts over the embedded fibre.

The samples were divided into two sets: one remained intact, while the other was exposed to elevated temperature and tensile loading. The structural integrity of the samples from both sets was assessed using SEM and the THz spectrometer. It was observed that the temperature affected the polymer matrix (resulting in matrix cracking) and the quality of the fibre/matrix interface (with fibres being pulled out). These analyses provided a deeper understanding of the degradation processes in GFRP under mechanical and environmental loading.