论文部分内容阅读
使用拉曼光谱研究了架桥纤维与裂缝微观力学,以超高分子量聚乙烯(UHMWPE)纤维为例,将纤维搭桥试样进行微拉伸试验,着重分析架桥纤维的止裂作用和架桥纤维/环氧树脂界面的应力分布,并对不同位置架桥试样的裂缝扩展速度和应力分布进行分析,并进一步运用剪切滞后模型,对架桥纤维在不同拉伸载荷下的应力分布进行了拟合分析,结果表明:架桥纤维能够分散部分外载应力,对于裂纹扩展具有显著的止裂作用。在低于UHMWPE纤维最大应变拉伸时,发现在裂缝中心位置处架桥纤维所承受的应力最大,其应力不超过2GPa,而基体树脂的应力可达到12GPa,架桥纤维/基体界面的应力传递达不到100%。以UHMWPE为架桥的应力传递模型呈“正抛物线”型,应力分布存在于粘结区、脱粘区和架桥区。
Raman spectroscopy was used to study the microcosmic mechanics of bridging fibers and fractures. Taking ultra-high molecular weight polyethylene (UHMWPE) fibers as an example, micro-tensile testing of fiber-bridging samples was carried out, with emphasis on crack arrest and bridging of bridging fibers Fiber / epoxy interface, and analyze the crack propagation speed and stress distribution of bridge specimens in different positions, and further use the shear lag model to study the stress distribution of bridge fiber under different tensile loads The fitting analysis shows that the bridging fiber can disperse part of the external stress and has a significant effect on crack propagation. At maximum tensile strain below the UHMWPE fiber, it was found that the bridging fibers at the center of the crack were the most stressed to 2 GPa, while the matrix resin had a stress of 12 GPa, bridging fiber / matrix interface stress transfer Less than 100%. The stress transfer model with UHMWPE as a bridge is “positive parabolic” and the stress distribution exists in the bond area, debonding area and bridging area.