Comparative Statistical Analysis and Tensile Behavior of Agave and Alfa Natural Fibers for Sustainable Composite Applications

Natural lignocellulosic fibers are increasingly used as sustainable reinforcements in polymer composites due to their low density and favorable specific mechanical properties. However, their mechanical behavior exhibits significant variability due to their heterogeneous structure. This study presents a comparative statistical analysis of the tensile properties of Agave (Agave americana) and Alfa (Stipa tenacissima) natural fibers. Single-fiber tensile tests were conducted on 23 specimens per fiber type using a gauge length of 40 mm. Tensile strength, Young’s modulus, and strain at break were determined, and statistical variability was analyzed using graphical tools and a Weibull distribution. The results show that both fibers exhibit comparable tensile strength values (~222 MPa for Agave and ~208 MPa for Alfa). However, Alfa fibers demonstrate significantly higher stiffness (Young’s modulus ≈15 GPa), while Agave fibers exhibit much higher strain at break (~19%), indicating a more ductile behavior. These complementary characteristics reveal distinct macroscopic tensile profiles. The findings highlight a stiffness–ductility trade-off and suggest that Alfa fibers are suitable for stiffness-driven applications, whereas Agave fibers are more appropriate for energy absorption. These results provide a useful basis for optimized fiber selection in hybrid bio-composites requiring tailored mechanical performance.