Numerical Modeling of the Flax / Glass / Epoxy Hybrid Composite Materials in Bending

The main purpose of this paper is the numerical analysis of the mechanical behaviour in bending of the both flax / epoxy composite material and E-glass / flax / epoxy hybrid composite material. Theoretical results are compared with the experimental results obtained in bending tests in case of the both kinds of composites. The finite element analysis (FEA) is used for simulation of the mechanical behaviour of the beams. Three kinds of beams made of laminated composite materials are modelled with finite element method: a beam made of eight flax /epoxy layers; a sandwich beam having two glass / epoxy layers as bottom shell layers, four flax / epoxy layers as core, and again two glass / epoxy layers as top shell layers (Hybrid 1); a beam made of four flax /epoxy layers and four glass / epoxy layers alternately arranged (Hybrid 2). The composite layers are modelled as orthotropic materials because the layers are reinforced either with glass or with flax bidirectional woven fabrics. The theoretical results obtained in finite element analysis were compared with the experimental results obtained in bending tests in terms of both the force-displacement curves (F-w) on the elastic domain and the equivalent modulus of elasticity Ex of the beam. Regarding the equivalent modulus of elasticity Ex it was found that the greater values of the errors were 6.11% and 5.58% and these correspond to the E-glass / flax / epoxy hybrid composite in weft direction and warp direction of the flax fabric, respectively.