Micro- and Macro-Mechanical Behavior of Inter- and Intra-Laminar Hybrid Composite Laminates with Natural and Synthetic Fibers: RVE Modeling and Classical Laminate Theory

This study investigates the micromechanical and macromechanical behavior of hybrid composite laminates composed of flax and E-glass fibers in an epoxy matrix. At the microscale, effective mechanical properties are determined using Representative Volume Element (RVE) modeling with Periodic Boundary Conditions (PBC), validated against analytical models such as the Modified Halpin-Tsai and the rule of mixtures. At the macroscale, the laminate stiffness is evaluated using Classical Laminate Theory (CLT). Two hybridization configurations with symmetrical ply stacking sequences are analyzed: inter-laminar, where flax and E-glass fibers are distributed in separate plies, and intra-laminar, where both fiber types are combined within each ply. Both configurations maintain a total fiber volume fraction (V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</inf>) of 0.5. Results show that the intra-laminar hybrid provides more balanced stiffness, whereas the inter-laminar configuration increases longitudinal stiffness but reduces transverse stiffness while enhancing shear properties. These findings provide insights into the influence of hybridization configurations on composite laminate performance.