Characterisation of fibre/matrix interfacial fracture energy using the single fibre peel experiment

Daan J Hottentot Cederløf,Bent F Sørensen

doi:10.1088/1757-899x/942/1/012029

Daan J Hottentot Cederløf, Bent F Sørensen

Open Access

https://doi.org/10.1088/1757-899x/942/1/012029

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Abstract

An experimental method for determining the interfacial fracture energy of a single fibre undergoing peeling is presented. Peeling of a partially embedded single fibre is observed under scanning electron microscopy. The fracture energy of the fibre/matrix interface is determined by analysis of the measured curvature of the fibre near the crack tip. This study serves as a demonstration of concept for the characterization of fibre/matrix interfaces through the single fibre peel experiment. A glass fibre/vinylester interface is used as an initial test case, from which obtained interfacial fracture energies was found to be in the range from 2 Jm−2 to 14 Jm−2.

Highlights

The utilization of fibre reinforced polymer (FRP) composites is widespread in industries such as aerospace, automotive and wind energy
The present paper presents a novel, scaled down adaptation of the experimental method shown by Kawashita et al [20] by analyzing the peeling of a single fibre inside a scanning electron microscope (SEM)
Summary An experimental method to characterize the fracture energy of fibre/matrix interfaces is presented

Summary

Introduction

The utilization of fibre reinforced polymer (FRP) composites is widespread in industries such as aerospace, automotive and wind energy. As the bridging fibres strain they transfer tractions between the crack faces and act as an energy absorbing (toughening) mechanism, reducing the delamination crack growth rate [4, 5] This toughening mechanism is not fully understood or controlled at the micro-mechanical level, meaning it cannot be reliably incorporated during design of critical composite structures. As evidence of the difficulty of isolating these two parameters: three different studies (using either analytical or numerical models) of the same test data (single fibre fragmentation test of glass/epoxy [13]) resulted in three different interfacial fracture energies: 120 Jm−2 [13], 12 Jm−2 [14] and 27 Jm−2 [10] These shear based experiments are not applicable in the case of fibre bridging where fibres are exposed to both peeling and pulling

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Conclusion