碳纤维及其二元混合填料增强复合材料导热性能的数值研究

发布时间：2018-05-03 23:28

本文选题：导热性能 + 复合材料　；参考：《青岛科技大学》2017年硕士论文

【摘要】：由于科技的飞速发展,复合材料的导热得到了广泛的应用,尤其填充型复合材料已经成为了广大学者们的研究热点。本文通过DIGIMAT软件得到了碳纤维填料及二元混合填充橡胶复合材料的代表体积单元模型,并通过有限元分析软件ANSYS对复合材料模型的导热性能进行数值模拟计算。主要讨论了碳纤维填充量、填充个数、长径比、弯曲度对复合材料导热性能的影响;二元混合填料填充顺序、填充配比及其中一种含量变化时对复合材料导热性能的影响。研究表明:在不同填料添加复合材料时,由于碳纤维有明显的各向异性,填料空间分布对复合材料导热性能的影响较为明显。碳纤维填充根数变化时复合材料热导率的变化微乎其微,复合材料热导率随着碳纤维填充分数的增大而增大,数值模拟结果与理论结果及实验结果的变化趋势一致;当碳纤维含量一定时,增大碳纤维的长径比能更好的提高复合材料的热导率。对于直形碳纤维,定向填充复合材料时的热导率最大。在复合材料中添加弯曲碳纤维时,其热导率随着弯曲度的增大先增大后减小。当弯曲碳纤维长径比变化时,拟合得到了不同区段长径比与复合材料导热性能的关系,利用拟合公式可以更好的预测不同长径比下复合材料的热导率。二元混合添加的复合材料,两种填料的添加顺序对复合材料导热性有一定的影响,先添加碳纤维时复合材料的热导率较高;两种填料在不同配比下,碳纤维对复合材料热导率起主导作用,随着碳纤维配比的增大,复合材料导热性随之增大;其中一种添加物含量一定时,复合材料热导率伴随另一种添加物含量的增加而增大。除了讨论碳纤维,还探讨了碳纳米管添加复合材料的热导率,将多壁碳纳米管等效为圆柱体。碳纳米管弯曲度增大,复合材料热导率下降;增加碳纳米管直径提高其填充量,复合材料热导率呈现出线性增大的趋势。
[Abstract]:Due to the rapid development of science and technology, the heat conduction of composite materials has been widely used, especially the filled composite materials have become the research hotspot of the majority of scholars. In this paper, the representative volume element model of carbon fiber filler and binary mixed filled rubber composite is obtained by DIGIMAT software, and the thermal conductivity of the composite model is simulated by finite element analysis software ANSYS. The effects of carbon fiber filling amount, filling number, aspect ratio, bending degree on the thermal conductivity of composites were discussed, and the effects of filling sequence, filling ratio and one of them on the thermal conductivity of composites were discussed. The results show that the space distribution of carbon fiber has obvious influence on the thermal conductivity of the composites due to the obvious anisotropy of carbon fiber when the composites are added with different fillers. The thermal conductivity of the composite increases with the increase of the carbon fiber filling fraction, and the numerical simulation results are consistent with the theoretical and experimental results. When the content of carbon fiber is constant, increasing the aspect ratio of carbon fiber can improve the thermal conductivity of composites better. For straight carbon fiber, the maximum thermal conductivity is obtained when the composite is filled in directionally. When the bending carbon fiber is added into the composite, the thermal conductivity increases first and then decreases with the increase of the bending degree. When the ratio of length to diameter of bending carbon fiber changes, the relationship between the ratio of length to diameter and the thermal conductivity of composites in different regions is obtained, and the thermal conductivity of composites under different ratio of length to diameter can be better predicted by using the fitting formula. The addition order of two fillers has a certain influence on the thermal conductivity of the composites, and the thermal conductivity of the composites is higher when carbon fiber is added first, and the thermal conductivity of the composites is higher when the two kinds of fillers are added in different proportions. Carbon fiber plays a leading role in the thermal conductivity of composites, and the thermal conductivity of composites increases with the increase of carbon fiber ratio, and the thermal conductivity of the composites increases with the increase of the content of the other additives when the content of one additive is constant. In addition to carbon fiber, the thermal conductivity of carbon nanotubes (CNTs) added into composites is also discussed, and the multi-walled CNTs are equivalent to cylinders. The thermal conductivity of the composites decreases with the increase of the bending degree of carbon nanotubes, and the increase of the diameter of carbon nanotubes with the increase of the filling amount, the thermal conductivity of the composites increases linearly.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB332

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