Hydrothermal aging effect on crushing characteristics of intraply hybrid composite pipes

In this study, the crushing properties of hybrid glass, basalt, and carbon fiber-reinforced composite pipes under a hydrothermal aging environment were investigated. Hybrid and non-hybrid composite pipes manufactured by filament winding technique were immersed in distilled water and seawater at 30 degrees C for four months. The water sorption parameters of the samples were calculated theoretically and weighed experimentally. Dry and aged pipes were subjected to quasi-static axial compression to examine aging effects on the crushing properties. The experimental weighing results showed that all composites exhibited a Fickian-like water absorption line. The non-hybrid basalt pipes were the most water-absorbing among all groups. In addition, the results proved that the hybridization effect in pipes is highly effective on water absorption parameters. In line with the results of nonhybrid pipes, hybrid pipes containing basalt fiber absorbed more water than other hybrid ones. Additionally, pipes aged in different environments showed that composite pipes absorbed more distilled water compared to seawater. Also, it was found that hydrothermal aging having adverse effects on the crushing characteristics of the pipes led to significant decreases. This can be explained by the degradation of the fiber-matrix interphase due to aging. However, maximum specific energy absorptions were achieved from non-hybrid carbon pipes regardless of environmental conditions. Also, the hybridization enhanced the crushing properties of the non-hybrid pipes that have lower characteristics. Additionally, it can be said that hybrid samples providing better stability in crushing showed better mean crushing load values since they mostly had a progressive crushing mode. The maximum mean crushing loads were obtained from the unconditioned hybrid GC samples as 36.2 kN which was 9.5 % and 34 % higher than unconditioned hybrid CB and BG samples. In conclusion, the study proved that the samples with low crushing properties can be improved by hybridization even if they are subjected to harsh environmental conditions.