عنوان مقاله [English]
The basic definitions of fatigue behavior for polymer materials are mentioned. Regarding the thermal fatigue of polymers that is due to the viscoelastic property of polymers is discussed and mechanical fatigue of polymers has been discussed in various aspects. Under the definition of mechanical fatigue, there is a three-step mechanism for the fatigue of polymers, initiation, propagation and fracture . Stress amplitude to the number of cycles to fatigue failure curves is one way to predict the fatigue behavior of the polymers. The tests used to predict the fatigue behavior of polymers are based on theoretical relations. According to Paris law, the fatigue crack growth rate graph is plotted in terms of the stress intensity factor, Which is very effective in predicting the fatigue behavior of materials. The fatigue behavior of polymers can be affected by many factors , About the effect of different experimental and structural variables Temperature, geometry, orientation, molecular weight, crosslinking, the effect of reinforcement, environmental factors such as solvent and moisture on Engineering polymers polycarbonate (PC) , Polyoxymethylene (POM), Polymethylmethacrylate (PMMA), polyamide( PA), polyphenylene oxide (PPO) and polytetrafluoroethylene (PTFE) have been discussed.