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The present study indicates the importance of using glass fiber reinforced polymer (GFRP) laminates with appropriate thickness and fibers orientation when exposed to harsh environmental conditions. The effect of different environmental conditions on tensile properties of different GFRP laminates is investigated. Laminates were exposed to three environmental conditions: (1) Freeze/thaw cycles without the presence of moisture, (2) freeze/thaw cycles with the presence of moisture and (3) UV radiation and water vapor condensation cycles. The effect of fiber configuration and laminate thickness were investigated by considering three types of fiber arrangement: (1) Continuous unidirectional, (2) continuous woven and (3) chopped strand mat and two thicknesses (2 and 5 mm). Microstructure and tensile properties of the laminates after exposure to different periods of conditioning (0, 750, 1250 and 2000 h) were studied using SEM and tensile tests. Statistical analyses were used to quantify the obtained results and propose prediction models. The results showed that the condition comprising UV radiation and moisture condition was the most aggressive, while dry freeze/thaw environment was the least. Furthermore, the laminates with chopped strand mat and continuous unidirectional fibers respectively experienced the highest and the lowest reductions properties in all environmental conditions. The maximum reductions in tensile strength for chopped strand mat laminates were about 7%, 32%, and 42% in the dry freeze/thaw, wet freeze/thaw and UV with moisture environments, respectively. The corresponding decreases in the tensile strength for unidirectional laminates were negligible, 17% and 23%, whereas those for the woven laminates were and 7%, 24%, and 34%. [ABSTRACT FROM AUTHOR]

Abstract This study investigates the flexural and impact behaviour of GFRP laminates after exposure to elevated temperatures. The effect of fibre's length and orientation, laminate's thickness, and exposure time is studied. A total number of 540 tests in terms of three-point bending and Charpy impact tests were conducted to obtain the mechanical properties. In addition, SEM analyses were carried out to investigate the degradation mechanisms. Finally, statistical study was conducted to investigate the contribution of each variable and develop probabilistic models using ANOVA and linear Bayesian regression method. The results showed that generally the flexural and impact properties of GFRP laminates decrease by increasing the temperature and time of exposure as well as decreasing the laminates' thickness. It is also observed that laminates with unidirectional fibres have the best performance under elevated temperatures, while laminates with randomly distributed fibres are the most vulnerable type. The performance of laminates with woven fibres are almost between those two other types. However, all types of the laminates lost almost all their flexural strength and impact energy absorption capacity at 300 °C. [ABSTRACT FROM AUTHOR]

This study investigates the tensile properties of various GFRP laminates after exposure to elevated temperatures. Fiber configuration, exposure temperature and laminate thickness were considered as the test variables. A total number of 180 specimens were tested in tension to obtain the mechanical properties of GFRP laminates. Alongside the mechanical tests, SEM analyses were conducted on selected samples before testing to investigate the resin, fiber, and their interface damages. Regardless of the sample type, it was generally observed that the reduction rate in the tensile strength increased with an increase in the exposure time and a decrease in the laminates' thickness. The results of tensile tests after exposure to elevated temperatures showed that the laminates with continuous unidirectional fibers performed the best, laminates with chopped strand randomly distributed fibers performed the worst, and the performance of the laminates with woven continuous fibers was somewhere in between. The maximum tensile strength reductions for the unidirectional and woven laminates were about 50% after exposure to 300 °C, whereas random chopped strand laminates lost almost all of their load carrying capacity under this exposure condition. [ABSTRACT FROM AUTHOR]