空间近零膨胀复合材料微观结构设计与分析

Microstructural Design and Analysis of Composite with a Near-zero Expansion Coefficient

中文关键词: 尺寸热稳定性  复合材料  纤维褶皱  微观热膨胀  碳纤维  氰酸酯树脂

英文关键词: thermal stability in dimension  composite  fiber wrinkles  microscopic thermal expansion  carbon fiber  cyanate ester

中文摘要:

      国家太空望远镜、空间引力波探测等前沿研究任务对尺寸热稳定复合材料构件提出了迫切的需求，这种复合材料构件是外空间高低温交替环境中大型精密光学平台保证成像/探测指向稳定的关键部件。然而，此类明显各向异性的复合材料在制造过程中极易产生纤维角度偏差。文中建立了含碳纤维褶皱的碳纤维/氰酸酯复合材料结构的微观模型，研究了纤维褶皱几何结构对材料各向热膨胀系数的影响，并进一步基于Layerwise理论建立了含褶皱的复合材料结构的热分析模型。研究表明：纤维褶皱主要影响复合材料纤维方向的热膨胀系数，纤维屈曲程度越大，结构局部受热后的热变形就越大；采用更薄的预浸料来增加堆叠层数，在一定程度上可减轻碳纤维褶皱缺陷对结构整体热稳定性能的影响。

英文摘要:

      The frontier research missions, including the national space telescope and the space gravitational wave detection, put forwards urgent demand for composite components with thermal stability in dimension. These composite components are crucial for ensuring directional stability for imaging/detection of large precision optical platforms in outer space’s alternating high and low temperature environment. However, these composites with obvious anisotropy are highly susceptible to fiber angle deviations during manufacturing. A microstructural model for carbon fiber/cyanate ester composites with carbon fiber wrinkles is established in this paper, the impact of fiber wrinkle geometry on the material’s anisotropic thermal expansion coefficient is studied and a thermal analysis model for composite structures with wrinkles is established based on the Layerwise theory. The study indicates that fiber wrinkles primarily influence the thermal expansion coefficient along the fiber direction in composites. The more severe the fiber buckling is, the greater the local thermal deformation after heated is. Employing thinner prepreg to increase the stacking layers can, to some extent, mitigate the effects of carbon fiber wrinkles on the structure’s overall thermal stability.