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为了揭示超高分子量聚乙烯(UHMWPE)纤维增强环氧树脂基复合材料的吸湿机制,利用ABAQUS有限元软件,建立二维模型,对此类复合材料的吸湿行为及吸湿应力进行研究。模拟计算了两种不同纤维分布模型内部的水分浓度场分布;根据获得的水分浓度场,对两种模型随温度及时间变化的吸湿应力场进行了分析。结果表明:水分在两种模型中的扩散都符合Fick扩散定律,纤维按正六边形分布模型比纤维随机分布模型更早达到吸湿平衡,但后者更符合实际情况,也与实验结果比较吻合;长时间的吸湿会导致材料内部吸湿应力达到很高的水平(>60MPa),温度越高,越早达到吸湿平衡,应力越大,最大的吸湿应力出现在纤维聚集最密集的基体区域,纤维随机分布模型的吸湿应力水平高于纤维按正六边形分布模型。
In order to reveal the hygroscopic mechanism of ultrahigh molecular weight polyethylene (UHMWPE) fiber reinforced epoxy resin matrix composites, a two-dimensional model was established by ABAQUS finite element software to study the hygroscopicity and hygroscopic stress of the composites. The distribution of moisture concentration in two different fiber distribution models was simulated. According to the obtained moisture concentration field, the hygroscopic stress field with temperature and time of the two models was analyzed. The results show that the diffusion of water in both models accords with the Fick diffusion law, and the fiber accords with the stochastic distribution model of fiber uniformly. The latter is more in line with the actual situation and the experimental results are in good agreement. Long-term moisture absorption will lead to the material to achieve high levels of hygroscopic stress (> 60MPa), the higher the temperature, the earlier the hygroscopic equilibrium, the greater the stress, the maximum hygroscopic stress in the fiber aggregation of the most intensive matrix region, the fiber randomly The hygroscopic stress level of the distribution model is higher than that of the regular hexagon distribution model.