Mechanical characterization and damage mechanism of a new flax-Kevlar hybrid/epoxy composite

A new composite, made with a woven constituted by Kevlar fibers and flax fibers in an epoxy resin is tested. Tensile and three-point bending tests are performed to identify mechanical properties and damage mechanisms. Compressive properties are identified by an inverse method using numerical simulation of the bending test. In addition, failure mechanisms are established by macroscopic and microscopic observations. The composite exhibits a strong non-linear anisotropic behavior. This non-linearity comes from the plastic strain of Kevlar fibers and flax fibers pull out, whereas the damaged modulus depends on the flax fibers damage. The hybrid composite has the same compression weakness as Kevlar composite, with compression properties that are lower than the tensile properties. Hybrid composite has an intermediate mechanical property between flax composite and aramid composite.