Influences of various natural fibers on the mechanical and drilling characteristics of coir-fiber-based hybrid epoxy composites

In this research, the hybrid natural fiber composite specimens were fabricated with a 64 wt% epoxy resin matrix, 20 wt% coir fiber, and 16 wt% of various natural fibers by the hand-layup method. The influences of various natural fibers (Coir, Jute, Flax, Cotton, Human Hair, Sisal, Kenaf, and Calotropis) on the mechanical characteristics (tensile, flexural, and impact strengths) and drilling properties (delamination factor and ovality) of the Coir-fiber based hybrid composite have been investigated. The maximum tensile strength (48.15 MPa), maximum flexural strength (47.87 MPa), and maximum impact strength (2.85 kJ m(-2)) have been obtained by Coir/Flax, Coir/Sisal, and Coir/Hair Fiber hybrid composite materials, respectively. The minimum delamination factor (1.0) and ovality (169.4 mu m) were obtained by coir/flax and coir/jute hybrid composite specimens when compared to other combinations of specimens. The delamination factor and ovality of the drilled hole of all combinations of hybrid composite specimens have been analyzed by scanning electron microscopy (SEM) images. The delamination factors of Coir/Flax and the drilling ovalities of Coir/Jute composite specimens are lower than those of other combinations of Coir-fiber-based composites.