ABSTRACT
Fatigue design of marine structures is important when the dissipation of the longterm variation of local stresses is addressed. Long-term variations of local stress are generally caused by environmental loads, predominantly by waves. The main contribution to fatigue damage comes essentially from these load effects, which are in the order of 10%–20% of the effects caused by extreme loads during the service life of the structure. Fatigue failures are catastrophic; they cause significant damages without warning. Physical problems of fatigue consist of (i) initiation of crack, (ii) stable crack growth, and (iii) unstable crack growth until rupture. Once the crack is initiated, it tends to propagate in an orthogonal direction of tensile stresses developed.
