三维编织C_(f)/Al复合材料T型件振动疲劳性能

Vibration fatigue behavior of T-shaped part of three-dimensional braided C_(f)/Al composites

采用真空压力浸渗法制备的三维编织C_(f)/Al复合材料具有良好的力学性能,在航空航天等领域的应用上具有较大潜力。本工作以三维编织C_(f)/Al复合材料为研究对象,对其在不同加载应力下进行振动疲劳实验,并观察疲劳实验后其断口处的微观结构。结果表明:加载应力越大,达到疲劳稳定阶段时T型件的固有频率降幅百分比也越大,即对T型件内部结构的破坏也越显著;对不同加载应力下的疲劳数据进行拟合,绘制S-N曲线,得到T型件振动疲劳损伤演变规律的数学模型,可用于预测三维编织C_(f)/Al复合材料的疲劳寿命;对实验后T型件进行断口处的宏观和微观分析,发现实验后的T型件呈现典型的脆性断裂特征。

Three-dimensional braided C_(f)/Al composites prepared by vacuum pressure infiltration method have good mechanical properties and great potential in aerospace applications.In this paper,the three-dimensional braided C_(f)/Al composites were taken as the research object,and the vibration fatigue tests were carried out under different loading stresses,and the microstructure of the fracture was observed after the fatigue tests.The test results show that the greater the loading stress is,the greater the percentage of natural frequency decrease is when T-shaped part reaches reach the fatigue stability stage,that is,the more significant the damage to the internal structure of T-shaped part is.By fitting the fatigue data under different loading stresses and drawing the S-N curve,the mathematical model of vibration fatigue damage evolution law of T-shaped part is obtained,which can be used to predict the life of three-dimensional braided C_(f)/Al composites.It is found that T-shaped part after the experiment shows typical brittle fracture characteristics through the macroscopic and microscopic analysis of the fracture.