Indian Journal of Science and Technology

Abstract

Objectives: This work investigates the flexural behaviour of Kevlar composite that are prepared by hand layup method. Methods/Analysis: Hand lay-up is a simple method for composite production. The epoxy resin of LY556 grade and an Araldite HY951 hardener is mixed with correct ratio. Then the Kevlar fiber is placed over the plate and an epoxy resin with a hardener is rolled over the fiber, by continuing which forms the layer by layer as per the requirement. Then after fabrication flexural test is carried out and then SEM analysis has been done to analyze the tested specimen. Findings: When tested under flexural load the composite breaks at 226 kN. It strains to maximum displacement of 6.7mm with ultimate stress of 5.56N/mm2 , that is it can withstand the maximum load of 226 kN with ultimate stress of 5.56N/mm2 . As we know that in the flexural test a uniform load is applied on the middle of the specimen, which tends a tensile stress is developed on the convex side and a compression stress is developed on the concave side of the specimen. This will create an area of shear stress along the middle line of the specimen resulting in its breakage. The Kevlar fibre having excellent strength survives even very high flexural loads and the result shows some unbroken Kevlar fibres in the middle even after the flexural load. Novelty/Improvement: While changing the orientation of the fibers from 00 , 300 , 450 and 900 the ultimate stress withstand by the specimen may also change. From this experiment we came to know that specimen may withstand the maximum of ultimate stress 5.56 N/mm2 at 450 fibre orientation.
Keywords: Flexural Testing, Hand Lay-Up Method, Kevlar, Scanning Electron Microscope (SEM)