MICROSTRUCTURE AND MECHANICAL PROPERTIES OF HEMP TECHNICAL FIBRES FOR COMPOSITE APPLICATIONS BY MICRO COMPUTED TOMOGRAPHY AND DIGITAL IMAGE CORRELATION

This research presents a novel experimental approach to characterize the non-linear behaviour of hemp fibres, by combining standard tensile tests with a detailed strain analysis during tensile loading. First, the strength and Young’s modulus distribution of technical hemp fibres of 78 different variants (fibre species and geographic location) were analysed using the modified Weibull distribution (length-based model), and one-way ANOVA statistical analysis. Next, strain mapping via digital image correlation analysis was used for evaluating the local mechanical behaviour heterogeneity along a technical natural fibre. The different tests performed allow a complete characterization of hemp fibres, which reveals 3 typical types of tensile stress-strain curves depending on their strength, and a complex and very irregular pattern of strain concentrations. Micro tomography is used to study the fibre microstructure and linked with the mechanical behavior analysis, in order to obtain a deeper understanding of the hemp fibre tensile behavior.status: publishe