The Improved Method of Risk Assessment for Falling Objects From the Crane of FPSO

It is very frequent for a crane to lift cargoes on the marine structure. The accident of falling objects often occurs and causes great damages to the marine structure. In this paper, the improved risk assessment of FPSO’s structural damage caused by falling objects is carried out. ANSYS/LS-DYNA is used to simulate the impact on the deck structure of FPSO and submarine pipelines respectively for several times. To gain the relationship between the maximum impact force and parameters of falling objects, it is necessary to fit the data obtained by simulation, so as to construct the failure function in Monte Carlo sampling during the subsequent work. Based on the method of DNV’s recommendation, the calculation method of collision probability about submarine pipelines will be improved. According to probability statistics, failure probability theory and energy method, the Matlab GUI program can be compilied to simplify calculation. Through the input data, the failure probability of the different segments of the pipeline can be obtained, then comparing the failure probability with the acceptance criteria. If the calculated failure probability does not meet the DNV’s acceptance criteria, we should find out the larger risk and give it some protective measures. This process provides a scientific basis for reducing the damage of the marine structure and how to take reasonable protective measures.