A Practical Design Tool For Wave Impact On Bow and Deck Structures

Abstract

This chapter describes a reliable tool for prediction of loads and structural responses from local wave impact on bow and deck structures on FPSOs and floating platforms, based on an analytical formulation with empirical calibration to measured data. A software package for practical engineering use is developed. The probability and nature of random, steep nonlinear wave events in a stochastic sea description is coupled with slamming force models and structural response analysis based on available experience in combination with model test calibration. The work is to a large extent making use of and combining existing tools and modules already available. Model test verification and calibration plays an important role. Empirical corrections can be applied to the calculated local wave elevation around the bow, as well as to the horizontal velocity of the water flowing across the bulwark. The approach is based on a combination of presently available theory with the aim to end up with a practical and robust tool, taking into account the most essential linear and nonlinear physical effects. The main physical effects are discussed through a research case study of an FPSO operating in conditions typical of the Norwegian sector of the North Sea. Simulations are in qualitative agreement with model tests and theoretical solutions.