Evaluation of strength of composite single-lap bonded joint exposed to hot water environment

Abstract

The main objective of this study is to investigate the effects of tap water environment on the strength of composite single-lap bonded joints. The specimens were manufactured in an autoclave by secondary bonding method and immersed in the fresh water of 71? in different periods which provide the joints with various moisture contents: 0, 0.2, 0.5, 1.0% and saturation. Tests were conducted in two environment conditions, viz., room temperature (RT) and elevated temperature (ET). The results show that the joint strength tested in RT environment increases until the moisture contents of 1% and then radically drops below the strength of the joint that was not exposed to the water environment. Similar phenomena were found in the ET environment but the strength reduction of the saturated joint is much more conspicuous than in the RT environment. The strength decrease in the saturated joints is attributed to the degradation of the adhesive strength and stiffness.