Structural Performance of Hybrid Fiber–Metal Laminates Reinforced With Natural and Synthetic Fibers: Tensile, Dynamic–Mechanical, and Residual Stress Behavior

Abstract

ABSTRACT This work studied how hybridization between natural and synthetic fibers influences the structural tensile performance, viscoelastic response, and residual stress distribution in fiber–metal laminates (FMLs). Two groups of laminates were produced: (i) fiber‐reinforced polymer (FRP) composites made from carbon, glass, and sisal fibers and (ii) FMLs, including nonhybrid and hybrid configurations with alternating natural and synthetic FRP layers. Tensile properties were determined using digital image correlation (DIC), and failure mechanisms were characterized by x‐ray microtomography. The viscoelastic response was analyzed by multifrequency dynamic mechanical analysis (DMA), while residual stresses were quantified using the layer removal method. The results showed that hybridization did not significantly affect tensile strength but increased strain capacity and energy dissipation due to sisal fibers. DMA indicated higher T g (up to 108°C) and E a (up to 520 kJ mol −1 ) when sisal plies were placed at the laminate core, reflecting enhanced confinement. Residual stress analysis confirmed reduced tensile stresses in aluminum and compressive stresses in FRP layers, leading to a more homogeneous stress state. These findings show that integrating natural fibers improves structural stress distribution and viscoelastic stability while reducing the synthetic fiber content in hybrid composite structures.