The impact of graphene reinforcement on z-pin and adhesively bonded composite for enhancing flexural strength of co-cured single lap joints
Anandhan Venugopal, P. Edwin Sudhagar, R. Vasudevan, Vignesh Suresh, N. Karthikeyan, Jesuarockiam Naveen
Abstract
The present work presents an investigation into the flexural characteristics of a composite joint consisting of various volume percent of carbon fiber reinforced polymer (CFRP) Z-pins inserted into a glass fiber reinforced polymer (GFRP) Co-cure single lap composite joint (CC-SLJ). The flexural strength of a single lap joint (SLJ) with 2.5 volume percent (vol%) CFRP Z-Pin is higher than that of other reinforcements with different Z-pin volume percentages. The bending strength of the SLJ was examined using an optimized 2.5 volume percent of Z-Pin with varying pin alignment (30°, 45°, 60°, and 90°), and it was found that 90° orientation showed good improvement in flexural strength. Compared to plain SLJ, 1.25% graphene nanoparticles (GNP) incorporated CC-SLJ significantly increased the flexural strength by 45.59%. SLJ with dual reinforcement of the 2.5 vol% CFRP Z-pin with 1.25 wt.% GNP exhibited high bending strength and multi-reinforcement of epoxy/GNP adhesive, and CFRP Z-pin and graphene-reinforced Z-pin were found with higher flexural strength enhancement. The results of the three-point bending test indicated a decrease in Z-pin strength and stiffness as the volume percentage of the pin increases. The specimen’s fractured surface was examined under a microscope following the testing procedure, and the images were captured to detect any indications of failure. It was found that adding graphene nanoparticles (GNP) and Z pins to the single lap joint (SLJ) makes the surface rougher and easier for the adhesive and adherend to stick to each other.