Contribution of field measurements in the study of composites reinforced with flax fibers during quasi-static tensile tests

TL;DR

This study uses field measurements and image correlation during tensile tests to analyze the mechanical behavior of flax fiber reinforced epoxy composites, validating optical methods against classical extensometry.

Contribution

It demonstrates the effectiveness of image correlation techniques for measuring strains in flax fiber composites during tensile testing, providing a non-contact alternative to traditional methods.

Findings

Optical measurements closely match classical extensometry results.

Image correlation effectively captures strain fields at low strain levels.

The method offers a promising tool for composite material analysis.

Abstract

This work is based on the study of the behaviour of flax fibres twill reinforced epoxy composites. The aim of the study is to determine the modulus of elasticity, Poisson coefficients and strength of these composites materials with image correlation. The specimens used in this work were manufactured by the infusion vacuum process and after subjected to quasi-static tensile tests. Two numeric cameras were disposed perpendicular to the front and to the side of the specimen so as to achieve a sequence of visible digital pictures during the test. The recorded pictures were analysed with the image correlation software 7D in order to calculate ad hoc measurements of displacements and strain fields. To check the validity of the results, measurements were compared to those obtained by classical extensometry. We found that, despite the low levels of strains, results of identifications from optical extensometry were very promising.