Research on Ultimate Strength of Hull Structure Based on Cumulative Plastic

The ultimate strength of hull structure becomes more and more important in the whole life cycle. Many ways of assessment are developed in the design stage and the calculation accuracy can meet the need of safety. However, all methods of assessment are based on one-time collapse. This certain method is in conflict with the random of wave environment. In this paper, stiffened plates with cyclic loads are researched. The ultimate strength, which considers cumulative plastic, is simulated by NLFEA. The results indicate that the assessment criteria based on one-time collapse may magnify the actual ultimate capacity. This will be very important to research the sea damage in non-extreme environment.