Experimental investigation on mechanical and vibration characteristics of Flax/CNSL composite laminates

Natural fiber reinforced composite materials are most increasingly used as sustainable structures in engineering industries due to their vast availability and eco-friendly nature. In this regard, an emphasis is given in the present work to the use of natural fiber in structural composite material in place of synthetic fibers for structural applications. In the present study, the mechanical properties and free vibration characteristics of a pure green composite laminate were experimentally evaluated. For complete understanding of the behaviour of green composite material, a second laminate is prepared using synthetic resin. Two types of composite laminates were fabricated by hand layup method. In the pure green laminate, natural flax fiber is embedded in cashew nut shell liquid (CNSL) resin and for the second laminate epoxy resin is used as matrix. The flax fiber is preferred due to its high mechanical strength among all the natural fibers. Alkaline treatment is done for the natural flax fiber before fabrication to remove impurities and also improve the surface adhesion. Both the laminates were tested for mechanical properties and free vibration characteristics according to ASTM standards. The experimentally evaluated tensile, flexural properties and modal frequency values of two types of laminates are reported and discussed.