海水环境下玻璃纤维增强复合材料力学性能演化规律研究

目的研究海水环境下海流能发电机组叶片用玻璃纤维复合材料力学性能的变化规律。方法在实验室内通过海水浸泡试验、拉伸试验、弯曲试验以及剪切试验,测定叶片用玻璃纤维树脂基复合材料的吸水特性,以及在人工海水介质中各项力学性能参数的演变规律。结果随着浸泡时间的增加,玻璃纤维树脂基复合材料吸水率先逐步增大、后趋于稳定,总吸水率约0.075%。抗拉强度呈先降低、后提高、又降低的趋势,抗拉强度最高可超过1100 MPa,最小值约为940 MPa。弹性模量和弯曲强度呈逐渐降低的趋势,弹性模量降幅约9.5%,弯曲强度降幅约为30%。弯曲模量变化起伏不定,变化幅度在15%以内。材料剪切强度呈先增大、后降低的趋势,最小值为189 MPa,较初始值高10 MPa。剪切模量呈先降低、后提高的现象,在浸泡28 d时,剪切模量最小,为16.4 GPa。结论玻璃纤维增强树脂基复合材料经过长期海水浸泡后,拉伸及抗剪切性能略有降低,但降幅不大,抗弯性能下降明显,需要在叶片结构设计和强度计算时,充分考虑抗弯性能衰减的负面影响。

Study on the Evolution of Mechanical Properties of Glass Fiber Reinforced Composite in Seawater Environment

The variation of mechanical properties of glass fiber reinforced composite for blades of marine current power generation units under artificial seawater was studied. In the laboratory, the water absorption characteristics of glass fiber reinforced polymer matrix composites for blades and the evolution of mechanical property parameters in the artificial seawater medium were investigated by seawater immersion test, tensile test, bending test and shear test. The results show that the water absorption of glass fiber reinforced polymer matrix composite increases initially and then gradually becomes stable with the increase of immersion time, and the final water absorption is about 0.075%. The tensile strength first decreases and then increases, and later it resumes decrease, while the maximum tensile strength can reach 1100 MPa and the minimum value is about 940 MPa. However, the elastic modulus and bending strength decrease gradually, and the decrease rates are about 9.5% and 30% respectively. The change range of bending modulus is within 15%. The shear strength of the material first increases and then decreases, with the minimum shear strength being 189 MPa, 10 MPa higher than the initial value. The shear modulus first decreases and then increases, and it decreased the lowest value, 16.4 GPa, after 28 d immersion. After immersion in seawater for a long time, the tensile and shear strength of the glass fiber reinforced resin matrix composites are slightly reduced, but the reduction is not large, while the bending strength are obviously reduced. Therefore, the negative effect of the degradation of the bending properties should be fully considered in the structural design and strength calculation of the blades.