Multi scale analysis by acoustic emission of damage mechanisms in natural fibre woven fabrics/epoxy composites.

C. Bonnafous^1a, F. Touchard¹ and L. Chocinski-Arnault¹

¹ Institut Pprime, CNRS – ENSMA - Université de Poitiers, Département Physique et Mécanique des Matériaux, ENSMA - Téléport 2, 1 avenue Clément Ader, BP 40109, F86961 Futuroscope Chassseneuil cedex

^a e-mail : claire.bonnafous@lmpm.ensma.fr

Published online: 10 June 2010

Abstract

This paper proposes to develop an experimental program to characterize the type and the development of damage in composite with complex microstructure. A multi-scale analysis by acoustic emission has been developed and applied to hemp fibre woven fabrics/epoxy composite. The experimental program consists of tensile tests performed on single yarn, neat epoxy resin and composite materials to identify their AE amplitude signatures. A statistical analysis of AE amplitude signals has been realised and correlated with microscopic observations. Results have enabled to identify three types of damage in composites and their associated AE amplitudes: matrix cracking, interfacial debonding and reinforcement damage and fracture. Tracking of these damage mechanisms in hemp/epoxy composites has been performed to show the process of damage development in natural fibre reinforced composites.