Failure Analysis of Adhesively Bonded GFRP Single Lap Joints After Cyclic Environmental Loading

Abstract

This experimental study provides an insight into failure mode analysis of adhesively bonded composite single lap joint that are tested in tensile shear after they have been subjected to cyclic heat and high relative humidity conditions. Glass fiber reinforced polymer (GFRP) composite is used with a liquid type adhesive. Changes in static load transfer capacity is examined in light of the failure analysis of fracture surfaces. Fracture surfaces of the bonded area is divided into different regions, and they are examined with both Scanning Electron Microscope and Energy Dispersive Spectrometry, as well as the cross-section of the adherend by Optical Metallography. Test data show that the ultimate failure load of GFRP/GFRP single lap joint is tripled by heat cyclic at high relative humidity, as compared to the baseline value at ambient condition. Detailed failure analysis, discussions, and conclusions are presented.