Accumulative plastic strain model for low cycle fatigue analysis of stiffened plates

In order to analyze the increasing accumulative plastic damage of ship stiffened plate, combing the interaction coefficient of stiffener and plate, with plastic strain of damage evolution as the control quantity, the low-cycle fatigue accumulative increasing plastic damage model and low-cycle fatigue life model for stiffened plates have been derived based on the theory of damage mechanics. The fatigue damage variable of the stiffened plate under cyclic loading was introduced into the accumulative plastic strain equation. Then by means of integral transformation, the evolution equation of axial accumulative plastic strain and the constitutive model for low-cycle fatigue life were deduced under low cyclic loading. The general high strength steel 402 was adopted, the theoretical evolution results from presented models of the accumulative plastic strain damage were compared with finite element modeling results. The results indicated that the established model well reflects the evolution law of the axial plastic strain of the stiffened plate under cyclic loading and is convenient to evaluate low cycle fatigue strength of ship structure.