A Comparison of Response-Based Analysis and Environmental Contour Methods for FPSO Green Water Assessment

Response-based green water analysis is carried out on an FPSO model with complicated effects of appendages and attachments. An efficient numerical approach developed and validated in our previous work is adopted in this study to evaluate the green water on FPSO, considering effects from bilge keel, spread mooring and portside risers in frequency domain. To accelerate the numerical study, an artificial neural network (ANN) is developed for nonlinear interpolation. Comparisons are made between relative wave elevation results from response-based analysis and traditional contour line approach using DNV and HDC methods. The response-based analysis using nonlinear model and simplified linear model are also compared to examine if nonlinear effect due to appendages and attachments on FPSO would affect the accuracy of response based analysis.