Stress Concentration Factors of Damaged Ship Side Panels

Floating production systems units (FPSOs or FSOs) converted from VLCCs are subject to damage in side panels due to overloading operations involving supply vessels. Although damages of small magnitude do not significantly affect the ultimate strength of the panel, the stress concentration in damaged regions may lead to the nucleation of cracks, in view of the long term operational life of these units. The proposed study evaluates experimentally and numerically stress concentration factors (SCFs) in damaged reinforced flat panels. A small scale model of a panel was manufactured and damaged to measure SCFs under cyclic in-plane compressive loading. The strain measurements where correlated with numerical results obtained from a finite element model which reproduces the laser mapped geometry of the panel. The calibrated numerical model can then be used to investigate SCFs of damaged panels under different conditions of damage position and depth. The study has shown that SCFs may significantly reduce the fatigue life of these panels when cyclic in-plane compressive loading is considered.