Damage to flax fibre slivers under monotonic uniaxial tensile loading

Usual testing methods developed for synthetic fibre bundles or slivers do not suit for plant fibres which exhibit specific characteristics. This paper reports damage investigation in flax fibre slivers (collection of disentangled and aligned fibre bundles more or less bonded by bark residues or other tissues) especially prepared for uniaxial tension testing using a new methodology and a dedicated device. The analysis of the acoustic emission data by using clustering methodology allowed categorizing three populations of damage mechanisms. Identification of the damage mechanisms was made by correlation of the tensile loading curves with acoustic emission data and by optical observations. Different damage parameters defined from the mechanical data (released elastic energy) were compared with those from acoustic data (energy of the hits). The results showed that the extension of damage vs. deformation can be expressed by using either of these two data sets. (C) 2014 Elsevier Ltd. All rights reserved.