Effect of Holes and Defects on Flexural Strength and Fracture Toughness of GFRP Composite under Three-Point Bending

Abstract

The glass fiber reinforced plastic (GFRP) composite materials are widely used in industries; these composites are coupled into large structures by drilled holes. In the present investigation, the characteristics of such drilled holes and defects were studied using GFRP composite samples with open-hole (at different positions), half-through holes and epoxy filled holes under three-point bend loading conditions. The “composite with epoxy filled holes” envisages maximum flexural strength, "composite with holes at a depth of 2.5 mm" showed intermediate and "composite with an open hole" exhibited minimum flexural strength. However, the flexural strength of the "composite" was increased when the relative distance between the holes was increased. The hypothesis of investigating the effect of defects in the form of Teflon exhibited significant results. The flexural strength was minimum in the case of multiple defects, however, it showed maximum fracture toughness. It was also observed that if the defect is present only at one end, it exhibited maximum flexural strength and minimum fracture toughness value.