Optimization of joint strength of adhesively bonded glass fiber epoxy based double strap butt joint

Abstract

Fiber reinforced composite laminates has various industrial applications. It is important to investigate the joining methods of composite laminates. In this research paper, the effect of overlap length (OL), surface roughness (SR) and adhesive layer thickness (ALT) on the strength and failure modes of adhesively bonded double strap GFRP (glass fiber reinforced epoxy based composite laminate) butt joint was investigated. The adhesively bonded double strap GFRP butt joints were prepared from unidirectional glass fiber and epoxy by hand layup technique as per ASTM standard. The number of experiments was optimised using Taguchi’s L9 approach. It is observed that the variation in overlap length has significant effect on butt joint strength. It is also observed that SR and ALT are less significant factors in comparison to OL. It is concluded that increase in ALT adversely affect the butt joint strength. The failure mode in specimens was generally thin layer cohesive failure or light fiber tear failure.