In-situ experimental and numerical investigation on fatigue crack growth in perfluorosulfonic-acid membrane with overloading effect

Fatigue crack growth behavior of perfluorosulfonic-acid membrane is investigated under single overload conditions by in-situ fatigue testing. The results show that the effected range of overload on cyclic plasticity positively correlates with the overload ratio (R_ol), indicating that overload-induced residual stress is aggravated with increase of R_ol. Besides, crack-tip sharpening occurred at higher R_ol can promote cyclic plasticity deformation, thus initially accelerating the crack growth. Moreover, the cyclic plasticity can be used to interpret the post-overload crack growth. Based on plastically dissipated energy, a numerical scheme incorporated with developed elastic-viscoplastic constitutive relationship is established to predict the fatigue crack growth.