碳纤维和SiO2纳米颗粒增强环氧树脂复合材料的压缩性能
Compressive performance of multi phase reinforced epoxy composites with carbon fibers and nano SiO2

纤维增强聚合物复合材料的压缩性能与聚合物基体力学性质密切相关。本文利用连续碳纤维（CF）和含有均匀分散的SiO2纳米颗粒改性的环氧树脂基体，制备了CF-nano SiO2/Epoxy微纳米多相复合材料单向层合板，并对其轴向压缩性能进行了系统的研究。试验表明，将纳米颗粒引入基体能够有效提高纤维增强聚合物基复合材料的压缩强度，占nano SiO2/Epoxy体积为8.7%的纳米颗粒可将复合材料的压缩强度提升约62.7%。基于单向层合板的弹塑性微屈曲模型对纳米颗粒的增强效应进行了理论分析。根据含纳米颗粒的环氧树脂在压缩过程中的损伤行为，提出了一套基于加卸载试验建立纳米复合材料基体压缩本构关系的方法。将模型获得的基体本构关系与经典复合材料弹塑性微屈曲模型耦合，能够较为准确地预测本研究制备的微纳米多相复合材料的压缩强度。经试验检验，预测结果与实测数值达到很好的一致性。 The compressive performance of fiber reinforced polymer composites is closed associated with the mechanical properties of polymer matrix. In this paper, unidirectional laminates of CF-nano SiO2/Epoxy multi-phase reinforced composites have been prepared using continuous carbon fibers(CF) and epoxy matrix with uniformly-dispersed SiO2 nanoparticles. The systematic experimental study has been carried out. It shows that the incorporation of nanoparticles into matrix contributes to the considerable enhancement of compressive strength of fiber reinforced polymers. The compressive strength of composites is found to be increased by 62.7% with the nanoparticle vlume ratio to nano SiO2/Epoxy of 8.7%. The reinforcing effects of nanoparticles have been theoretically analyzed based on the elasto-plastic micro-buckling model for unidirectional laminates. A method was proposed to construct the constitutive relation during compression for nanocomposite matrix through loading-unloading tests, according to the damage behaviors of epoxy matrix containing nanoparticles. The compressive strength of the prepared multi-phase reinforced composites can be well predicted by combining the classic elaso-plastic micro-buckling model and constructed constitutive relation of nanocomposite matrix. The experimental verification demonstrates the good agreement achieved between the predicted results and the measured data. 国家自然科学基金（11772131；11712132；11712134