RESEARCH ON ACCUMULATIVE PLASTIC DAMAGE FOR LOW-CYCLE FATIGUE ANALYSIS OF HULL NOTCHED PLATE

摘要

Ship plates suffer from both low-cycle fatigue damage and accumulative plastic damage under asymmetric low-cycle fatigue loading. The accumulative plastic damage under asymmetric low-cycle fatigue loading was investigated using the Chaboche model for numerical analysis, during which the accumulative plastic deformation localized around the region of the notch root was taken as the control parameter. The corresponding experiments were conducted and compared with the results of theoretical analysis in this paper. Based on a series of calculations by finite element simulation, the influence of stress amplitude, mean stress, stress ratio, and initial notch radius on the accumulative plastic strain were investigated and discussed. Based on the fatigue fracture toughness at the root of the ship plate, this paper presents a new assessment approach for additional damage caused by plastic deformation under asymmetrical low cycles.