Hybrid Laminates Reinforced with Natural and Synthetic Fibers: Experimental Characterization and Preliminary Finite Element Assessment for Prosthetic Applications

Abstract

Highlights: What are the main findings? Among the four hybrid configurations evaluated, the flax–glass–flax (LVL) laminate demonstrated the highest tensile strength and flexural deformation capacity. Its elastic behavior was reproduced through finite element modeling, showing close correlation with experimental results (≤0.86% stress error, ≤5.25% strain error). The orthotropic elastic properties of the LVL laminate were experimentally characterized and confirmed to be suitable for structural use in prosthetic applications. What is the implication of the main finding? The LVL laminate offers a viable and more sustainable alternative to fully synthetic composites in load-bearing prosthetic components, maintaining mechanical reliability while incorporating natural fibers. The finite element model developed using the experimental data enables accurate simulation and design of hybrid composite prostheses. The proposed fabrication method—vacuum-assisted hand lay-up with additional weight—proves to be a practical and low-cost route for producing high-performance bio-composites. Four configuration laminates made of flax, glass, and basalt were fabricated via vacuum-assisted hand lay-up with added weight and tested under ASTM D3039 and D790. The flax–glass–flax lay-up exhibited the highest tensile strength and flexural strength. Orthotropic elastic properties were determined from remanufactured 90°-rotated specimens. A hexahedral-meshed finite element model using these inputs under a 5256 N load predicted the stress and strain within 1% and 5% of the experimental values. These findings demonstrate that flax–glass hybrids offer mechanical reliability, sustainability, and affordability for next-generation prosthetic applications.