Reliability and Damages of Ship Structures

This paper presents three areas of ship reliability. The first part treats the buckling collapse of deck plates having initial distorsion. At ultimate load a hinge line is formed across a deck after successive collapses of weaker panels under the extreme wave load during ship's life. The second part deals with the fatigue damages using a mathematical model with uncertainty of crack initiation in group of structural members, for example, row of bottom floors in cargo ships. Further, the design criteria for fatigue stress is discussed. The last part is a discussion on the reliability for corrosive damages of ships of several ages and kinds. The theoretical results of last two areas are compared with the observation obtained from survey reports of ships registered with Nippon Kaiji Kyokai.