Fatigue Life Prediction of Composite Laminates under Block Loading
The loading sequence effect and life prediction of carbon fiber-reinforced polymer (CFRP) composite materials were experimentally investigated in this paper. All fatigue tests of block loading under four stress ratios R (including 0.1, 0.5, 10 and –1) were carried out on the servo-hydraulic Shimadzu testing machine. The fatigue damage index derived from the linear Palmgren–Miner rule was as reference to evaluate the damage degree. The life prediction model based on residual strength theory was proposed. The experimental results showed that the effect of loading sequence on the fatigue damage was obvious. The relation between the parameter of the proposed model and the stress ratio was studied depending to different failure mode. At last, the contrast of prediction and experimental data indicated that the proposed model had enough accuracy to predict fatigue life of block loading for composite materials.