Fatigue Strength of a Typical Ship Structural Detail: Tests and Calculation Methods

In previous years, several large-scale specimens have been fatigue tested in the Ship Structures laboratory of the Dipartimento di Ingegneria Navale e TecnologieMarine (DINAV) of the University of Genova (Italy). They represent the crossing of a T-shaped beam into deep web plates, simulating either a primary supporting member or bulkhead plating. Each specimen is characterized by two joints, both watertight but with different geometry. The purpose of this paper is to review all the available test results using calculation methods for fatigue strength of welded structural details, namely: nominal stress approach, local stress approaches and the fracture mechanics approach. Test results allow SNcurves to be drawn which can be used for these and similar details, quite common in shipbuilding. Moreover, calibration of stress concentration factors and coefficients in the various fatigue life calculation methods is possible using the experimental data.