Vibration fatigue behavior of T-shaped part of three-dimensional braided Cf /Al composites

Abstract

Three-dimensional braided Cf/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 Cf/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 Cf/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 .

Keywords

• three dimensional braided cf/al composites
• t-shaped parts
• vibration fatigue
• s-n curve
• brittle fracture