大丝束CF/EP汽车地板VARTM模拟与高温力学性能

VARTM simulation and high temperature mechanical properties of large tow CF/EP automobile floor

汽车轻量化是全球面临的共同问题,采用更具成本优势的大丝束碳纤维(CF)增强复合材料是实现汽车轻量化结构化的重要途径。然而,大丝束碳纤维在液体成型时,单束过多的纤维丝易导致纤维束内微观浸润困难,易产生干斑、气泡等缺陷。同时,传统的汽车电泳烘干工艺对复合材料的高温性能提出了挑战。鉴于此,本文采用0°/90°双轴向缝编大丝束碳纤布和耐高温环氧树脂(EP),开展了纤维渗透率测试和汽车地板真空辅助树脂传递成型(VARTM)模拟优化研究,设计、制造了成型模具,成功试制出汽车地板样件,超景深显微镜观测显示纤维束内和层间浸润良好,无明显缺陷。高温在线拉伸和应变测试显示,温度对材料拉伸模量影响显著而对强度影响不大,180℃高温下应变恢复能力良好,表明该材料在高温下仍具备较好的强度和抗蠕变性能,该结果对指导复合材料能否通过传统汽车的电泳烘干工艺具有重要意义。

The lightweight of automobile is a global problem.The large tow carbon fiber(CF)reinforced composites with low cost are considered to be an important way to realize the lightweight and structured of automobile.However,for the liquid forming process of large-tow CF,the micro-wetting in the fiber bundle is usually difficult because of too many filaments in a single bundle,which may lead to defects such as dry spots and bubbles.At the same time,the traditional automobile electrophoresis drying process also poses a challenge to the high temperature performance of composites.In view of this,the fiber permeability test and the simulation and optimization of vacuum assisted resin transfer molding(VARTM)for automobile floor were carried out by using 0°/90°biaxial stitching of large-tow CF cloth and high temperature resistant epoxy(EP)resin.The forming mold was designed and manufactured,and the automobile floor sample was trial-produced successfully.The observation of super depth of field microscope showed that the fiber bundles and interlayers were infiltrated well,and there were no obvious defects.High temperature on-line tensile and strain test indicated that temperature had a significant effect on tensile modulus but little effect on strength,and the strain recovery ability was good at 180℃,which revealed that the composites still had excellent strength and creep resistance at high temperature.The results were of great significance to guide whether the composites could pass the traditional electrophoretic drying process of automobile.