Fatigue performance of MDYB-3 PMMA under different temperature

The fatigue behaviors of MDYB-3 PMMA (polymethyl methacrylate) in uniaxial tension under cyclic loading of constant amplitude at different temperatures are investigated experimentally. The S-N curves at the typical temperatures are obtained by fitting experimental data according to the fatigue power function. It is found that the fatigue strength decreases violently with the temperature increases. On the basis of the equations of linear regression at five experimental temperatures, the fatigue life assessment equation considering temperature effect is established using polynomial fitting method. The fatigue envelope lines roughly represent the stress levels at given life cycles under different temperatures. In addition, the relationships between the total fatigue strain and cycle ratio are analyzed, and the second stages of development of the strain at different temperatures are obtained, from which the fatigue life of PMMA can be predicted. The results of present investigation offer the basis and reference for the design and the life-evaluation analysis of aircraft windscreen and canopy.