Tensile fracture and failure behavior of technical flax fibers

The apparent tensile strength of technical flax fibers was determined in single-fiber tests at various clamping lengths (20, 40, and 80 mm) and the outcome was compared with literature data. It was demonstrated that the strength of flax at each clamping length obeyed the two-parameter Weibull model. The failure mode and sequence were studied in situ (i.e., during loading) by SEM and acoustic emission (AE). The failure sequence (axial splitting of the technical fiber along its elementary constituents, radial cracking of the elementary fibers, multiple fracture of the elementary fibers) concluded reflected the hierarchical build-up of the flax bast fibers. To the above failure events AE amplitude ranges were assigned. (C) 2003 Wiley Periodicals, Inc.