Developing empirical formulations to predict residual strength and damages in tension-leg platform hulls after a collision

During service life, a TLP is under potential damage caused by attendant vessel collisions. The influence of local dents on the maximum strength of TLP is a challenge in ocean engineering structures. Proper regulations outside the industrial practices are required to identify and rehabilitate the strength of these structures subjected to collision. Existing design methods require improvement to accurately predict the ultimate strength of TLPs subjected to accidental collision. Thus, it is imperative to develop viable approaches for predicting the residual ultimate strength of such structures. This paper aims to establish practical modeling techniques and equations to predict the residual strength of dented TLPs subjected to combined axial compression and hydrostatic pressure. The proposed computational models employ nonlinear finite element analyses (NFEA) considering the dynamic effects of materials properties such as strain rate and dynamic fracture strain. A series of NFEA of actual TLP with different collision scenarios and parameters were carried out using ABAQUS software. The empirical equations were provided through the database out of the NFEA results. The reliability of derived empirical formulations was compared with NFEA results, existing formulations, and test data.