Bilinear approach to tensile properties of flax composites in finite element analyses

Flax fibers show potential in bio-efficiency compared to conventional composite fibers with good mechanical properties. The tensile behavior of flax fibers shows a nonlinear stress–strain relation. Within this work, a bilinear elastic–plastic approach is described, which is based on the generalized Hill potential theory and easily applicable in ANSYS. The method was used to model the nonlinear stress–strain behavior under quasi-static tensile loading of flax fiber-reinforced laminates. Hashin failure mechanisms using the stress–strain data of the bilinear model are applied as well. The results were compared to experimental data, carried out using pre-impregnated flax fibers in three types of tensile test specimens. The layups of investigation were [ 0 ] 6 , [ 90 ] 6 and [ ± 45 ] 8 . The strain was evaluated using the non-contact, digital image correlation measurement ARAMIS. Good agreement with the test results was achieved, and the method of bilinear elastic–plastic modeling of flax fiber-reinforced structures was evaluated as simple but effective for quasi-static elongation under uniaxial tensile loading.