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以多向铺层碳纤维增强双马来酰亚胺(T700/HT280)复合材料和双马来酰亚胺(HT280)树脂为研究对象,采用刚度降的方法研究高温老化对复合材料抗疲劳性能的影响。测量了复合材料和树脂的质损率,并利用FTIR、超声C扫描和动态力学热分析仪(DMA)对高温老化前后材料的化学结构、内部损伤、动态力学行为进行了分析。实验结果表明,随着高温老化时间的延长,两种材料的质损率均呈现先迅速增加后缓慢增加的变化规律。经历长期高温老化后,树脂发生了热氧老化。HT280树脂动态力学性能的变化归因于后固化与热老化效应,T700/HT280复合材料则归因于后固化、热老化和界面脱粘的综合作用。高温老化后T700/HT280复合材料刚度下降的速率与幅度明显小于原始态,表明高温老化后复合材料的后固化与热老化的强化效应明显,导致其抗疲劳性能有一定的提高。
The multilayered carbon fiber reinforced bismaleimide (T700 / HT280) composites and bismaleimide (HT280) resin were used as the research object to study the effect of high temperature aging on the fatigue properties of composites influences. The mass loss rate of the composites and resin was measured. The chemical structure, internal damage and dynamic mechanical behavior of the composites before and after aging at high temperature were analyzed by FTIR, ultrasonic C-scan and dynamic mechanical thermal analyzer (DMA). The experimental results show that with the aging time of high temperature, the mass loss rates of the two materials increase rapidly and then slowly increase. After experiencing long-term high temperature aging, the resin undergoes thermal oxygen aging. The change of dynamic mechanical properties of HT280 resin is attributed to the effect of post-cure and thermal aging. T700 / HT280 composites are attributed to the combination of post-cure, thermal aging and interfacial debonding. After the high temperature aging T700 / HT280 composite stiffness decrease rate and amplitude was significantly less than the original state, indicating that the composite material after high temperature aging hardening and heat aging of the strengthening effect is obvious, resulting in its fatigue resistance increased to some extent.