Research area
Nonlinear and Stochastic Dynamics
Rare and extreme responses of marine systems — parametric roll, capsize, and dynamic stability in a random seaway.
Some of the most consequential behaviours of a ship are also the rarest: parametric roll, broaching, and capsize occur infrequently but dominate the risk picture. Studying them means treating the seaway as a stochastic process and the vessel as a strongly nonlinear system.
Parametric roll and vulnerability
Work in this area develops methods to assess a hull’s vulnerability to parametric roll in irregular seas. Roll dynamics can be recast in terms of total energy and approximated as a Markov process, so that first-passage times give a design metric for comparing hulls and wave environments without long time-domain Monte Carlo campaigns. Related approaches use Melnikov and Markov methods, and Volterra-series representations of the restoring arm, to capture the nonlinear and time-varying hydrostatics that drive parametric excitation.
Extreme response without endless simulation
A second theme is estimating the probability of extreme responses efficiently. Nonlinear time-domain simulation — including Froude–Krylov and hydrostatic forces over the instantaneous wetted surface — is essential for capturing phenomena such as parametric roll, but rare-event statistics need more than raw simulation length. The group develops semi-analytical and stochastic tools that keep the physics while making risk assessment practical for design.