Effect of Hygrothermal Aging on Mechanical Properties of Glass Fiber/Epoxy VER Composites
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摘要: 为掌握玻璃纤维/环氧乙烯基酯树脂复合材料经湿热老化后的力学性能,采用真空辅助注射成型技术,制作玻璃纤维/环氧乙烯基酯树脂复合材料层合板,并根据复合材料压力容器在服役过程中的受力特点,利用水切割技术将层合板制成弯曲和剪切试样。考虑到压力容器的使用工况,对试样进行浸泡加速老化试验,分析了在不同温度和周期下复合材料的质量和力学性能变化。结果表明,随着浸泡时间的增加,复合材料的弯曲和剪切性能逐渐降低。相比于浸泡时间的影响,温度对复合材料性能的影响更显著,如在90 ℃水中浸泡6周后,复合材料的剪切强度、弯曲强度以及弯曲模量降为初始值的1/2。
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关键词:
- 玻璃纤维/环氧乙烯基酯树脂 /
- 水浸泡 /
- 老化 /
- 力学性能
Abstract: In this paper, the mechanical properties of glass fiber/epoxy vinyl ester resin (GF/epoxy VER) composite after hygrothermal aging were studied. The GF/epoxy VER composites laminates were fabricated by vacuum assisted injection molding technology. According to the stress characteristics of composite pressure vessels during service, bending and shearing samples were made by water cutting technology. Considering the working environment of pressure vessel, accelerated aging tests were carried out on the samples soaked in water to analyze the changes of the mass and mechanical properties of the composites at different temperatures and periods. Results show that bending and shear properties of composite materials decrease with the increase of water immersion time. The effect of temperature on the properties of composites is more significant than that of soaking time. If immersed in 90 ℃ water for 6 weeks, the shear strength, flexural strength and flexural modulus of the composite are reduced to half of the initial value.-
Key words:
- glass fiber/epoxy vinyl ester resin /
- water immersion /
- aging /
- mechanical properties
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表 1 湿热老化试验方案
Table 1. Wet heat aging test program
Temperature/℃ Number of shear specimens Number of bend specimens Temperature/℃ Number of shear specimens Number of bend specimens 25 18 18 90 18 18 50 18 18 Unaged 3 3 75 18 18 表 2 复合材料在不同温度下的吸水参数
Table 2. Water absorption parameters of composites at different temperatures
Temperature/℃ ${\omega }{_{\mathrm{s} } }$/% A/(10−6 mm2·s−1) D/(10−3 mm2·s−1) S/10−3 25 0.72 2.06 1.17 2.41 50 0.81 2.31 1.43 3.30 75 0.95 2.71 1.92 5.20 90 1.20 3.43 2.00 6.86 表 3 复合材料在不同温度和老化时间下的弯曲力学性能
Table 3. Bending mechanical properties of composites at different temperatures and aging time
Temperature/℃ Bending strength/MPa Unaged 1 week 2 weeks 3 weeks 4 weeks 5 weeks 6 weeks 20 663.21±35.76 573.19±5.62 564.99±11.01 546.40±20.46 537.47±17.57 531.71±4.20 497.96±44.22 50 663.21±35.76 568.40±48.72 557.23±32.80 530.29±29.27 527.81±23.14 522.56±38.24 480.33±26.20 75 663.21±35.76 524.70±23.80 474.84±23.54 446.91±48.68 403.94±56.79 400.68±20.07 383.33±7.14 90 663.21±35.76 434.02±38.77 387.33±15.31 367.55±0.93 366.35±6.06 326.88±4.28 276.05±24.52 Temperature/℃ Bending modulus/GPa Unaged 1 week 2 weeks 3 weeks 4 weeks 5 weeks 6 weeks 20 14.32±0.71 14.00±0.92 13.54±0.40 13.11±0.66 13.14±0.59 12.98±0.97 12.08±1.28 50 14.32±0.71 13.71±0.27 12.91±0.53 12.92±1.37 12.61±0.30 12.47±0.83 10.64±0.71 75 14.32±0.71 13.45±0.22 11.80±0.06 11.67±1.11 11.42±0.49 11.33±0.44 9.86±0.40 90 14.32±0.71 10.89±1.14 10.00±1.39 9.30±1.69 7.96±0.44 7.24±1.42 5.34±3.52 表 4 复合材料在不同温度和老化时间下的剪切力学性能
Table 4. Shear mechanical properties of composites at different temperatures and aging time
Temperature/℃ Shear strength/MPa Unaged 1 week 2 weeks 3 weeks 4 weeks 5 weeks 6 weeks 20 32.50±1.32 30.00±6.42 28.19±1.14 27.28±2.21 26.69±0.11 24.73±1.75 22.23±1.45 50 32.50±1.32 29.78±2.87 28.06±1.49 26.59±0.31 26.52±3.14 22.46±1.74 20.59±2.80 75 32.50±1.32 28.00±6.34 27.92±1.29 26.73±3.48 26.35±1.91 24.21±0.96 18.31±6.01 90 32.50±1.32 27.46±1.30 24.49±0.07 24.01±1.32 21.80±0.57 19.87±2.53 13.95±5.75 Temperature/℃ Shear strength change rate/% Unaged 1 week 2 weeks 3 weeks 4 weeks 5 weeks 6 weeks 20 0 −7.69±0.21 −13.26±0.04 −16.06±0.07 −17.88±0.00 −23.91±0.06 −31.60±0.05 50 0 −8.37±0.09 −13.66±0.10 −18.18±0.06 −18.40±0.05 −30.89±0.10 −36.65±0.06 75 0 −13.85±0.20 −14.09±0.04 −17.75±0.11 −18.92±0.03 −25.51±0.03 −43.66±0.19 90 0 15.51±0.04 −24.65±0.02 −26.12±0.04 −32.92±0.02 −38.86±0.08 −57.08±0.18 -
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