An improved Manson–Coffin model for fatigue life prediction of large crude oil storage tanks via environment temperature and surface roughness

Large crude oil storage tanks (LCOST) are subjected to cyclic loads during use, and they always work in variable environment. Accurately predicting the fatigue life of LCOST is of great significance for their usage. In order to obtain fatigue life of LCOST, the effects of surface roughness and environment temperature on fatigue life are analyzed and discussed. A modified Manson–Coffin method (MC) is proposed based on the Manson–Coffin fatigue life prediction model, taking into account the effects of surface roughness and environment temperature. The fatigue life prediction of the improved method is compared with the conventional MC method for 45# steel and the results turn out that the modified MC method is more precise. The fatigue life of LCOST is predicted by means of the analysis and calculation of stresses, and the validity of the method is verified by comparing with its service life, which provides a method for fatigue life prediction.