Efficient assessment for the pitchpoling risks of a generic wave energy converter based on first passage statistics

Of the rapidly emerging wave energy converter (WEC) designs, many can be essentially categorized as moored, floating, cylindrical structures. Their capsizing risks under random waves (i.e. dynamic instability) haven't been investigated adequately. The stochastic averaging proves to be an efficient approach providing quantitative assessments of dynamic instabilities. This study has adapted stochastic averaging to assess the pitchpoling risks of a generic moored floating WEC under random waves. Studies reveal that the statistics from stochastic averaging can be correlated reasonably with the statistics from the time domain simulations. Without requiring numerous simulations, the obtained first passage statistics could formulate a semi-analytical dynamic stability criterion for WEC designs. Sensitivity analysis have been performed with respect to various parameters, including wave period, mooring setup, initial condition and geometry modification.