## 1 Introduction
(2018) studied the impact of freak waves and second-order Stokes waves on a fixed elastic deck using a strong coupled fluid-structure interaction method and discussed the hydroelastic responses. [PERSON] et al. (2019) conducted physical experiments to investigate the impact of a freak wave on a tension-leg platform, which suggested that a high-crest freak wave could induce violent motions of a floating platform and snap loads in tethers. [PERSON] et al. (2020) utilized the smoothed particle hydrodynamic (SPH) method to simulate the effect of freak waves on a semi-submersible platform and compared and analyzed the motion response characteristics of the semi-submersible platform under two mooring systems: a tension leg platform (TLP) and taut spread mooring (TSM). Focusing on the local wave-structure interaction phenomena, freak waves with huge wave heights usually lead to significant green water events. Therefore, some other scholars have examined the green-water loads caused by freak waves. [PERSON] et al. (2018) found asymmetric and irregular characteristics in green water caused by freak waves when compared to regular waves. [PERSON] et al. (2018) studied the impact of green-water loads caused by Peregrine breather-type freak waves on a flat deck, and proposed an empirical formula for the quick prediction of nonlinear freak-wave forces on such deck structures. [PERSON] et al. (2013) studied the wave height, deck pressure, and superstructure pressure of a fixed FPSO under the influence of freak waves. [PERSON] et al. (2019) investigated the mechanism and impact form of green water events under the influence of freak waves, and analyzed the ship's motion response, water variation and pressure. [PERSON] et al. (2019) discussed the relationship between ship motion response and green water events under the influence of freak waves, and the effect of ship speed on wave-ship interaction, revealing the impact of freak-wave peaks and sequences on roll, heave, and impact pressure. The serious wave loads during green water events may lead to severe structural responses and even local damages of the ship bow, especially to the deck and breakwater structures. However, previous research focused on the structural analysis during bottom slamming, bow flare slamming and stern slamming. The structural responses and local damage of the deck and breakwater structures were rarely examined. For example, [PERSON] et al. [26] used computational fluid dynamics (CFD) and FEM methods to study the water entry slamming of the ship's body and predict the structural hydroelastic response. [PERSON] et al. [27] established a three-dimensional FEM model of a 1700 TEU container ship's bow structure and studied the dynamic response of bow flare slamming under impact loads, using a one-fold-plate-thickness deformation criterion to determine whether the structure buckled. [PERSON] et al. [28] studied the dynamic response of bow flare structures under impact loads using LS-DYNA software. [PERSON] et al. [29] proposed an uncoupled CFD and FEM method to study the local dynamic response of bow flare on a 21,000 TEU container ship under extreme impact loads. [PERSON] et al. [30] studied the slamming response of the stern of an LNG ship using numerical simulation. [PERSON] et al. [31,32] studied the impact of green-water loads caused by freak waves on the deck and deck-house structures, which further obtained the displacement of the structures using a strong coupled fluid-structure interaction method. However, the structures they used were fixed deck models simplified as plates and beams. From these studies, it is seen that the interaction between freak waves and marine structures has been widely studied in the aspects of wave force, motion response, longitudinal strength and green water events. Nevertheless, the green-water loads of a ship with free motions induced by freak waves and the corresponding structural analysis of the deck and breakwater structures have rarely been examined.