Tensile, Compressive, and Flexural Characterization of CFRP Laminates Related to Water Absorption

Abstract

CFRP structures are often exposed to humid environment resulting in water absorption and causing property degradation. Water swelling and its effect on tensile, compressive, and flexural properties were investigated according to ASTM standards. Fracture modes were evaluated by analyzing micrographs of fracture areas. The specimens were cut from twill wave CFRP composite plates fabricated using a vacuum infusion technique. Some of them were immersed in water prior to being mechanically tested. It was found that tensile strength, as well as compressive, and flexural strength and moduli decreased due to water swelling, but fracture strain was found to increase due to water swelling. The most severely affected by water swelling is flexural strength (decreased by 25.72%), and the least is compressive modulus (decreased by 1.89%). Tensile specimens underwent fibre breakage followed by matrix cracking, compressive and flexural specimens showed fibre buckling followed by kinking and crushing where flexural specimens failed in their compressive side. In conclusion, water absorption has a bad impact on the composite strength.

Enhanced damage tolerance and fracture toughness of lightweight carbon-Kevlar fiber hybrid laminate

“…Similar behavior of CFRP laminate has also been shown by others. 31,32 KFRP laminate shows more like a ductile response, followed by a stepwise stress drop after reaching maximum stress. Oliwa 33 has demonstrated KFRP laminate that exhibits comparable behavior.…”