Strength failure criteria analysis for a flax fibre reinforced composite

Natural fibre composites are being utilized increasingly in high-performance, structurally demanding applications, in part because of their material properties and in part because they are a more sustainable choice compared to other engineering materials. However, there is a current lack in understanding of best practices for strength modelling of natural fibre composites. This study aims to understand how well common failure criteria predict strength in multidirectional flax fibre composite laminates. Four failure criteria are compared to experimental data from tension and compression tests of flax composite laminates with five different layups. Parametric optimization is performed on each criterion in order to determine the optimal strength, stiffness, and interaction parameters. In conclusion, the Hashin and Puck failure theories are recommended because they have the smallest error compared to experimental data. Values for parallel-to-fibre shear strength are also presented, and they are found to be comparable to the shear strength of conventional glass fibre composites with similar matrix materials.