Fatigue Design Method of Ship Structural Members Based on Fatigue Crack Growth Analysis

摘要

Instead of the current fatigue design method, a new fatigue design procedure has been proposed, and is applicable to an initial fatigue design, a residual fatigue life prediction and a fatigue crack damage analysis. The new procedure is derived based on (1) the concept of a fatigue crack growth analysis (the Paris law), (2) the authors' new storm model for the time history of stress occurrence and (3) a new sailing model instead of the all headings model. To improve more the proposed fatigue design procedure, the effect of following factors on fatigue life is examined: (1) an initial surface crack size occurred at weld toe. (2) a mean stress corresponding to full and ballast loading conditions. (3) a time history of stress occurrence. (4) a relative angle (the angle at which a ship encounters a wave).