温度对碳纤维平纹布正交层合板拉伸疲劳性能的影响

The fatigue performance of composites decreases with the temperature increase. The effect of temperature should be considered when determining the composite structure life. In this paper, the tensile fatigue properties of orthotropic composite laminates in CTD, RTD and ETD environment were tested. The S-N curves in three environments were obtained, and the influence of temperature on fatigue properties of composite was analyzed. Based on experimental results, the fatigue finite element model (FEM) of composite under the temperature condition was established to simulate the fatigue life and damage mechanism. The linear fitting fatigue results show that the maximum fatigue stress in CTD environment is a little smaller than that in RTD environment, while the maximum fatigue stress in ETD environment is obvious less than that in RTD environment. In CTD environment, the fracture surface of fatigue failure is relatively neat, the fiber is basically broken at the same longitudinal position, and the matrix near the fracture surface is relatively intact. The degree of fracture is very low, and there is no delamination; In RTD environment, there is no obvious delamination at the fracture surface of the specimen; In ETD environment, there is obvious delamination along the thickness with fibers pulled out and serious matrix cracks. The FEM analysis shows that the fatigue failure of the specimen is brittle fracture under CTD environment, which shows flat fracture section and narrow fracture area, while the fracture section is not smooth and uniform with relatively wider fracture area under RTD and ETD environments.