Mechanical behavior of natural sisal fibers

Natural fibers are gaining a significant amount of attention as reinforcement in composite materials. In this work we present a systematic experimental investigation on the mechanical performance of sisal fibers. Tensile tests were performed and Young's modulus determined. Weibull statistics were used to quantify the degree of variability in fiber strength, at the different gage lengths. The Weibull modulus decreased from 4.6 to 3.0 as the gage length increased from 10 mm to 40 mm, respectively. Fatigue tensile tests were performed at stress-levels ranging between 80 to 400 MPa. The sisal fibers did not exhibit fatigue below a maximum fatigue level of 320 MPa. SEM was used to investigate the failure mode of the fibers. The failure mechanisms will be described and discussed in terms of the fiber microstructure as well as the defect population in the fibers.