Abstract: A numerical simulation technology of fatigue life prediction of pressure vessel based on cyclic J-integral is developed. Through finite element numerical calculation and experiment test on pressure vessel containing inner portrait surface crack, the results show that initia ellipse surface crack tends to round surface crack gradually during fatigue developing and keeps the round shape to develop. The velocity of crack fatigue development is not uniform and presents the trend of more quickly. The numerical simulation results of fatigue life prediction based on J have higher precision than those of K based and satisfy the engineering requirement. This technology have important application value for fatigue life prediction of pressure vessel in use containing defects.

Key words: Cyclic J-integral, Fatigue life, Numerical simulation, Pressure vessel