Study on ultimate strength for stiffened plates with elasto-plastic damages

Abstract

To investigate the ultimate strength of stiffened plates under cyclic uniaxial loadings considering fatigue damage, a damage-coupled cyclic constitutive model of marine high strength steels (HSSs) is first established based on continuum damage mechanics. Fatigue damages are involved in the constitutive modelling, which is calibrated and verified by the experimental data. Then, the application of the constitutive model is implemented to established ultimate strength assessment method of stiffened plates under cyclic loadings. Cyclic loading tests of stiffened plates are carried out to obtain the hysteresis behaviours and validate the assessment method. The influences of cyclic hardening and fatigue damage are discussed in detail. The results show that the ultimate strengths of stiffened plates linearly decline in the first several loading cycles, then tend to be stable. The fatigue damage shows a trivial share on ultimate strength reduction in the limited cycle, while the cyclic hardening considerably contributes.