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为了研究形状记忆合金(SMA)丝增强环氧树脂复合材料的界面粘结行为,首先通过单纤维拔出试验测定了SMA/环氧树脂界面的粘结强度,重点考察了埋入深度对界面极限粘结强度及其拔出行为的影响。然后,结合ABAQUS有限元分析方法,利用基于表面内聚力行为的单元对SMA丝拔出过程中应力分布随拔出时间的变化关系进行了模拟。最后,针对SMA/环氧树脂复合材料界面粘结强度较弱的缺陷,提出了利用纳米SiO2改性SMA丝表面提升材料界面粘结强度的方法,并通过拔出试验进行了验证。结果表明:随着埋入深度从1.0cm增加到1.5cm和2.0cm,最大拔出载荷显著增加,平均界面粘结强度却逐渐下降。当纤维埋入深度为2.0cm时,在0.300s时临界脱粘出现。利用在SMA表面涂覆纳米SiO2颗粒的方法可以增加纤维的表面粗糙度,进而有效提高SMA丝增强环氧树脂复合材料的临界拔出强度。研究结论为SMA丝在实际工程领域中的应用提供了理论指导。
In order to study the interface bonding behavior of shape memory alloy (SMA) wire reinforced epoxy composites, the bonding strength of SMA / epoxy interface was first measured by single fiber pullout test. The effect of embedding depth on the interface limit Bond strength and its pull out behavior. Then, with ABAQUS finite element analysis method, the relationship between the stress distribution and pull-out time of SMA wire during pull-out process was simulated based on the unit of surface cohesion behavior. Finally, aiming at the defects of SMA / epoxy composite interface with weak bonding strength, the method of using nano-SiO2 to modify the surface of SMA wire to improve the bonding strength of the material was proposed and verified by pull-out test. The results show that with the embedding depth increasing from 1.0cm to 1.5cm and 2.0cm, the maximum pull-out load increases significantly, and the average interfacial bond strength decreases gradually. When the fibers are embedded at a depth of 2.0 cm, critical debonding occurs at 0.300 s. The method of coating nano-SiO2 particles on the SMA surface can increase the surface roughness of the fiber, thereby effectively improving the critical pull-out strength of the SMA wire to enhance the epoxy resin composite material. The conclusion of the research provides theoretical guidance for the application of SMA wire in practical engineering.