Ultimate strength of ship hull girder with grounding damage

The paper presents a method for the assessment of residual strength of a ship hull damaged in a grounding accident. The strength assessment is based on a coupled beam (CB) method that allows time-efficient analysis. As a case study the method is applied to a double hull tanker. Three grounding damages are defined based on IACS guidelines and with a dedicated grounding assessment tool. The CB method is based on an assumption that global bending response of a ship can be estimated with the help of beams coupled to each other by distributed springs. To include the damage opening in the residual strength assessment, the structural elements in the damaged region are excluded by reducing their elastic modulus. For the validation of the CB method, the residual strength is also evaluated with non-linear finite element method. Good correlation between the methods is reported.