J.S.M Moghadam - Mechanical Engineering Department, Ferdowsi University of Mashhad, Mashhad, Iran
H.E Toosi - Mechanical Engineering Department, Ferdowsi University of Mashhad, Mashhad, Iran
S.A Razavi - Mechanical Engineering Department, Ferdowsi University of Mashhad, Mashhad, Iran

Thick-walled vessels have many applications in military, chemical, and aerospace industries and also in nuclear facilities. Increasing the internal pressure inside these vessels can take some of the layers of the vessel into the plastic zone. If this happens several times, we will see the accumulation of plastic strains called ratcheting. This paper assumes that the thick-walled vessel is subjected to a cyclic internal pressure between zero and a maximum value. In order to analyze this phenomenon, first, we present the quasi-creep method, and then we validate this method using the finite element Abaqus Software based on the combined hardening model. Then we employ this method to evaluate the effect of internal pressure and thickness of the vessel on the amount of ratcheting strains in different cycles. In the end, the results of this research and the accuracy and speed of the quasi-creep method are stated.

Thick-walled cylinder, Ratcheting, Quasi-creep, Combined hardening