中文摘要：

为了揭示短纤维无纺布对碳纤维增强树脂基复合材料（CFRP）层板层间韧性的影响规律,测试了不同面密度（1.95、3.90、7.80和15.60 mg/cm^2）和不同纤维平均长度（0.8 mm和4.3 mm）的碳纤维无纺布增韧的CFRP层板I型层间断裂韧性。实验结果表明：对于不同短纤维增韧的CFRP层板,平均长度为0.8mm的短纤维增韧效果优于平均长度为4.3mm的短纤维,并且面密度为7.8mg/cm^2、厚度约为150μm、平均长度为0.8mm的碳纤维无纺布显著提高了CFRP层板的层间断裂韧性,与未改性的CFRP层板相比,其能量释放率最大可提高99%。光学显微镜观察结果表明环氧基体中长度为0.8mm的短纤维具有三维交织结构,该结构可以有效地阻止裂纹的扩展;SEM观察结果表明短纤维从环氧基体中的脱粘和拔出以及短纤维周围环氧基体的塑性变形是CFRP层板的主要增韧机制。研究结论为层板短纤维增韧技术的应用奠定了基础。

英文摘要：

In order to reveal the effect laws of non-woven short fiber tissues on interlaminar fracture toughness of carbon fiber-reinforced polymer（CFRP）laminates,the mode I interlaminar fracture toughness of CFRP laminates toughened with non-woven carbon fiber tissues of different areal densities（1.95,3.90,7.80 and 15.60mg/cm^2）and different average lengths of fibers（0.8mm and 4.3mm）were investigated.The experimental results show that for the CFRP laminates toughened with different short fibers,the toughening performance of short fibers whose average length is 0.8mm is better than that of short fibers whose average length is 4.3mm,and the non-woven carbon fiber tissue with the areal density of 7.8mg/cm2,thickness about 150μm and average length of 0.8mm significantly enhances the interlaminar fracture toughness of CFRP laminates,the energy release rate is improved by 99%at best comparing with that of unmodified CFRP laminate.The optical microscopy observation results show that the short fibers whose length is 0.8 mm have 3Dinterleaved structure in epoxy matrix,the structure can prevent the cracks form propagation effectively.SEM observation results indicate that the debonding and pullout of short fibers from epoxy matrix and plastic deformation of epoxy matrix around short fibers are the main toughening mechanisms of CFRP laminates.The research conclusions lay down the foundation for application of short fibers toughening technique for laminates.