纤维增强纳米SiO_2复合隔热材料的力学性能研究

Study of Mechanical Properties of Fiber Reinforced Nano-silica Composites

采用干法成型工艺制备了纤维增强纳米SiO2复合隔热材料,考察了成型压力和纤维长度对复合材料力学性能的影响。结果表明,成型压力越大,复合材料承受压力载荷的能力越强,纤维表面致密的纳米级颗粒覆层对纤维起到的保护和应力缓冲作用越强,抗折强度越高。增强纤维长度对抗压强度影响不大,纤维越长,抗折强度越高,但当纤维过长时会因分散困难而导致抗折强度下降,故适宜的纤维长度为5mm。此外,采用等效包容体理论建立了纤维增强复合材料细观力学分析模型,并对纤维增强机理进行了深入分析和探讨。

Fiber reinforced nano-silica composites were prepared by dry molding technology. The effects of molding pressure and fiber length on mechanical properties of the composites were investigated. The results indicate that the ability to endure pressure will be improved with the increase of molding pressure. Moreover, the bending strength will be enhanced by the protection of dense nano-particles cladding layer. Fiber length is proportional to bending strength, but it has little influenee on compressive strength. However, overlong fibers may lead to the decrease of bending strength because of difficult separation. So the suitable length of fibers here is 5mm. In addition, mechanical analysis mold of fiber reinforced composites was established on the basis of equivalent inclusion theory. The strengthening mechanism of fiber was also comprehensively analyzed and discussed.