Draft summary

This document outlines methods for measuring the strain distribution for randomly oriented chopped strand- or fibre-reinforced plastic composites, based upon the general principles given in ISO 527-4. The methods are used to statistically evaluate the inherent variation of strain-based properties. The main purpose of this document compared to existing standards is to evaluate the strain distribution due to the random orientation of chopped fibres, while ISO 527-4 is sufficient for evaluating only the bulk elastic modulus. This standard provides two methods for evaluating an inherent strain distribution of the material, Method A as using DIC analysis system and Method B as using several strain gauges with a short gauge length. The methods are suitable for use with fibre-reinforced thermosetting and thermoplastic composites incorporating discontinuous or chopped reinforcements such as mats, chopped strands or tapes, long-fibre injection or combination of such reinforcements. The methods are not normally suitable for continuous fibre-reinforced materials which generate homogeneous strain distribution on the surface of the test specimen.