Property evolution of CFRP@GFRP hybrid composite rod exposed in the distilled water
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摘要: 碳纤维增强树脂复合材料(CFRP)@玻璃纤维增强树脂复合材料(GFRP)混杂复合材料杆体发挥碳纤维的高力学、疲劳性能与玻璃纤维的低成本、高变形能力等优势,在桥梁与海洋工程中具有巨大应用潜力,如跨海大桥斜拉索。针对CFRP@GFRP混杂复合材料杆体在服役环境下长期性能演化,本文采用加速试验方法研究蒸馏水环境下CFRP@GFRP混杂复合材料杆体的水吸收及界面剪切性能长期演化规律。研究结果表明:混杂复合材料杆体皮、芯层及杆体吸水行为符合Fick定律,GFRP皮层扩散系数最大,CFRP芯层次之,混杂复合材料杆体由于在皮/芯界面层形成吸水屏障而扩散系数最小。浸泡在蒸馏水环境下芯层、皮/芯界面及皮层界面剪切强度下降,这是由于浸泡过程中水分子通过氢键形式与树脂基体结合形成结合水,导致树脂基体发生水解和塑化及纤维/树脂界面脱黏。基于Arrhenius加速理论建立了混杂复合材料杆体在三座典型桥梁服役环境下的界面剪切强度预测模型。
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关键词:
- CFRP@GFRP混杂复合材料杆体 /
- 湿热老化 /
- 吸水性能 /
- 界面剪切强度 /
- 长期寿命预测
Abstract: Carbon fiber reinforced polymer (CFRP)@glass fiber reinforced polymer (GFRP) hybrid composite rod plays the advantages of carbon fiber (such as high mechanical and fatigue performances) and glass fiber (such as low cost and high deformation capacity) and has great application potential in bridge and ocean engineering, such as cross-sea bridge cable. In view of the long-term performance evolution of CFRP@GFRP hybrid composite rod under the service environment, the present paper adopted the experimental acceleration method to study the water absorption and interface shear performance evolution of CFRP@GFRP hybrid composite rod under the distilled water environment. The results show that the absorption behavior of hybrid composite rod is in accordance with Fick law. The diffusion coefficient of glass fiber shell is the largest, carbon fiber core is the second, and the hybrid composite rod is the smallest due to the water absorption barrier between the shell/core interface layer. Immersed in distilled water leads to the decrease of the interface shear strength of core, shell/core and shell layers. This is attributed to the water molecules combined with the resin matrix in the form of hydrogen bond to form the bond water, resulting in the hydrolysis and plasticization of the resin matrix and the debonding of the fiber/resin interface. The prediction model of interface shear strength of hybrid composite rod was established in three typical bridge service environments based on the accelerating theory of Arrhenius. -
表 1 CFRP芯层、GFRP皮层及CFRP@GFRP混杂复合材料杆体的扩散系数D
Table 1. Diffusion coefficients D of CFRP core, GFRP shell and CFRP@GFRP hybrid composite rod
10−7mm2/s Type 20℃ 40℃ 60℃ CFRP core 2.68 3.77 7.67 GFRP shell 3.08 6.03 9.14 CFRP@GFRP 1.26 2.30 8.14 表 2 CFRP芯层、GFRP皮层及CFRP@GFRP混杂复合材料杆体水吸收拟合度(R2)
Table 2. Degree of fitting R2 of water uptake of CFRP core, GFRP shell and CFRP@GFRP hybrid composite rod
Type 20℃ 40℃ 60℃ CFRP core 0.99 0.94 0.96 GFRP shell 0.96 0.99 0.94 CFRP@GFRP 0.98 0.99 0.99 表 3 CFRP@GFRP混杂复合材料杆体寿命预测的回归系数τ及R2
Table 3. Regression coefficient τ and R2 of life prediction for CFRP@GFRP hybrid composite rod
Type Immersion
temperature/°Cτ R2 CFRP core 20 310.2 0.98 40 224.7 0.96 60 178.6 0.96 GFRP shell 20 561.3 0.93 40 337.5 0.98 60 253.8 0.97 CFRP core/GFRP
shell interface20 641.4 0.92 40 508.1 0.98 60 360.5 0.97 表 4 CFRP@GFRP混杂复合材料杆体寿命预测的回归系数Ea/R及R2
Table 4. Regression coefficient Ea/R and R2 of life prediction for CFRP@GFRP hybrid composite rod
Type Strength
retention/%Ea/R R2 CFRP core 50 1350 0.99 60 1350 0.99 70 1350 0.99 80 1350 0.99 90 1350 0.99 GFRP shell 50 1 945 0.97 60 1 945 0.97 70 1 945 0.97 80 1 945 0.97 90 1 945 0.97 CFRP core/GFRP shell interface 50 1398 0.96 60 1398 0.96 70 1398 0.96 80 1398 0.96 90 1398 0.96 Notes: Ea—Activation energy of materials; R—Universal gas constant; R2—Degree of fitting. 表 5 CFRP@GFRP混杂复合材料杆体剪切强度寿命预测的时移因子参数
Table 5. Time-shift factor for life prediction of interface shear strength for CFRP@GFRP hybrid composite rod
Type T0/°C Time-shift factor Shenyang Youth Bridge (T=8.8°C) Jiangsu Yangtze River
Bridge (T=15.9°C)Hainan Century Bridge (T=26.9°C) CFRP core 20 1.20 1.07 0.90 40 1.61 1.43 1.21 60 2.09 1.86 1.56 GFRP shell 20 1.30 1.09 0.85 40 1.99 1.68 1.31 60 2.89 2.44 1.90 CFRP core/GFRP
shell interface20 1.21 1.07 0.90 40 1.64 1.45 1.22 60 2.14 1.90 1.59 Notes: T—Annual mean temperature data from China Meteorological Observatory (www.nmc.cn) for 2019;T0—Immersion temperature in the lab environment. -
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