Suzuki et al. (2013) estimated the collision risk in wind farms comprising bottom fixed-type wind turbines caused by 6788 GT drifting ships. Li et al. (2013) and Li et al. (2014) developed a numerical model of the monopile wind turbine and vessel through a proposed external dynamic link library (DLL) under various incident wave conditions. The shielding effects of the vessel were considered. They found that wave directions and length made a difference in impact behaviors for the wind turbine and the structural response of the vessel.

The transient response and damage of grouted connections in monopile-supported OWTs subjected to ship impacts were analyzed using LS-DYNA by Mo et al. (2018), as shown in Figure 4. A finite element model simulating a 2000-ton vessel colliding with a 5 MW monopile OWT was developed, considering the nonlinear behavior of structural materials. They found that significant damage could be caused even at a low impact velocity of 2 m/s, with the strain rate effect notably influencing the response and damage of the grouted connection.

Niklas and Bera (2022) examined the impact collision performance between a monopile wind turbine and an offshore supply vessel to investigate the effect of adopted strain-based failure criteria on damage. It was demonstrated that a six-fold underestimation of the ship damage was due to the strain failure standard. Ladeira et al. (2022) evaluated the low-energy impacts between monopile wind turbines and service ships using the proposed semi-analytical methodology. The validation of this method was achieved by comparison with nonlinear finite element method (FEM) code LS-DYNA.

Hamann et al. (2013) analyzed the collision behavior between a fully loaded single-hull tanker and a 6 MW gravity-base foundation wind turbine using the FEM tool. The calculated contact forces were compared with a simplified approach. The impacts of water depth, foundation diameter, and seabed embedment were also evaluated. The FEM tool effectively optimized the gravity base foundation designs for ship collisions in a cost-effective method. Osthoff and Grabe (2015) analyzed the collision characteristics between a double-hull tanker and a gravity base foundation wind turbine using the FEM code under various water levels. The effect of swell on the collision performance of the FOWT and damage to the tanker was also examined and discussed. Presencia and Shafiee (2018) developed a methodology to minimize the collision risks of multiple kinds of vessels used for maintenance with OWTs with a gravity base foundation. It was found that the collision risks were significantly subjected to the maintenance of those under a corrective replacement. Alerechi et al. (2018) analyzed the dynamic response of a reinforced concrete gravity platform exposed to crash loads from an offshore transporting vessel using ANSYS EXPLICIT DYNAMICS. Finite element analysis (FEA) was employed to evaluate the structural integrity of the offshore platform under collision scenarios with impacting velocities of 5 m/s, 10 m/s, 16 m/s, 50 m/s, and 100 m/s. The results revealed that increasing velocity was able to proportionally upgrade deformation.

Biehl and Lehmann (2006) utilized numerical crash tests to compare multiple wind turbines colliding with vessels under various scenarios. They determined that the monopile foundation was the most reliable. Tripod and jacket OWTs must be examined in detail before being rated. The nacelle impacts and collision modes of the whole structures were examined. Lee (2013) investigated the dynamic response of a tripod wind turbine during boat collisions and compared the damage to that of a turbine protected by a rubber fender. Figure 5 shows the collision scenarios between the vessel and a tripod wind turbine. The results demonstrated that the rubber fender system using a high Mooney–Rivlin coefficient provided the most effective collision protection for the substructure. Additionally, a minimum fender thickness was found to reduce adverse effects on the wind turbine structure.

Widjaja et al. (2013) assessed the impact energy and structural response of wind turbines based on the jacket platforms under extreme states in the Vietnamese water area. It was found that the maximum value of vessel impact energy could be decreased by adjusting structural design standards and offshore operations. Zhang et al. (2014) evaluated the collision behavior and dynamic response of a wind turbine with a jacket foundation using the automatic dynamic incremental nonlinear analysis (ADINA) method. In addition, the ship velocity, joint thickness, and impact points were calculated and compared. Hsieh (2015) proposed a simplified analytical method to accurately and efficiently estimate the impact load and structural response of the jacket foundation after a collision with a vessel based on the super-element concept. Travanca and Hao (2015) explored the dynamic response and energy dissipation of a wind turbine after collisions with ships based on the finite element (FE) framework. The effects of ship sizes, platform layout, and even ship–structure interactions were also extensively considered and examined. The data showed that plastic deformation mechanisms were more suitable for high-energy ship collision analysis on the jacket OWTs. Moulas et al. (2017) studied the damage to wind turbine foundations based on monopile and jacket structures by collisions with 4000-ton support vessels using a nonlinear finite element analysis (NLFEA) approach. They identified various collision scenarios, analyzed damage extent, evaluated reinforcement effects, and offered insights for designing more collision-resistant wind turbine foundations.

Hao and Liu (2017) evaluated the anti-impact performance of monopile, tripod, and jacket foundations for wind turbines using LS-DYNA. The FE model of the vessel and wind turbine is shown in Figure 6. Maximum collision forces, damage areas, bending moments, steel consumption, and nacelle accelerations were analyzed, revealing that jacket foundations exhibited the lowest collision forces and damage, along with moderate bending moments and steel use. It was concluded that jackets provided the best overall anti-impact performance under low-energy collisions.

Pire et al. (2018) evaluated the crashworthiness of the jacket base OWTs for each deformation mode based on the analytical formulations. A good accordance was shown between the data and the numerical results calculated by the nonlinear finite element tool. A simplified analytical method was introduced for estimating the anti-collision ability of an oblique cylinder for the jacket OWTs impacted by the stem of a striking ship by Buldgen et al. (2014) and Ladeira et al. (2023a). The collision angles were compared and examined. Closed-form solutions were derived for horizontal and vertical cylinders using the upper-bound method, and an interpolation formula was proposed for various angles. The numerical data were validated with those simulated by LS-DYNA. Although there was a high agreement, the model was limited to high-impact energy.

Although many studies have been carried out on the dynamic response of fixed-bottom offshore wind turbines to ship collisions, most calculations have used simplified models, which have a negative impact on the accuracy of the results. Additionally, soil–structure interaction effects have not been fully accounted for in these studies and need further consideration.

Echeverry et al. (2019) analyzed the anti-collision performance between a spar-type platform and a 5000-ton vessel using LS-DYNA under various collision scenarios. The effect of properties such as nacelle mass, hydrodynamic forces, and mooring line tension of the FOWT were also investigated.

Ren et al. (2022) investigated the collision performance between a spar-type platform and a ship using a nonlinear FEM framework, as shown in Figure 7. The displacement, acceleration, collision forces, and incurred structural damage of a FOWT under various impact speeds were examined and discussed. It was found that the collision does more damage to the spar-type platform than the whole wind turbine.

A theoretical model was developed by Zhang et al. (2021), Zhang and Hu (2021), and Zhang and Hu (2022) to analyze the dynamic responses of an OC3-Hywind spar-type offshore floating wind turbine subjected to ship impacts, considering a collision duration of 0.5 s and an impact force of 2000 kN. The model integrated hydrodynamic effects using an added mass matrix and applied rigid body impact principles to derive expressions for energy dissipation and other kinetic parameters. A time-domain analytical program was developed to evaluate dynamic responses with parametric case studies revealing sensitivity to variables such as collision force and wave conditions. The surge and pitch motions of the wind turbine under ship collision with various impact velocities are shown in Figure 8. In addition, the effect of impact speed and tower flexibility of the FOWT, as well as the deformability of the ship, were studied under various wind-wave combined loading cases.

Ha and Kim (2022) investigated the dynamic response and impact characteristics of a 5 MW spar-type platform with ship collision using ABAQUS. The results were validated by comparing them to experimental data. It was found that the residual strength of the FOWT was reduced by 4.1% reduction after collision with a ship with a velocity of 3 m/s.

Yu and Bo (2021) studied the collision performance between a DTU Wind 10 MW wind turbine with an OO-STAR semi-submersible platform and an 8800-ton vessel under parked and operating conditions using LS-DYNA and OrcaFlex. The results simulated by LS-DYNA showed that a ship striking at 2.5 m/s could destroy 0.5 m concrete walls, while a ship moving at 10 m/s could damage 1 m concrete walls. In addition, the OrcaFlex calculations showed that nacelle accelerations generally exceeded safety limits, with tower stress and mooring forces also potentially surpassing thresholds, particularly under operating conditions. Guo J. et al. (2022) studied the collision between a vessel and tension leg platform wind turbines (TLPWTs) by LS-DYNA based on the fluid–structure interaction method and constant added mass. It was demonstrated that all tension legs were not slack during ship–TLPWT collisions due to prestress.

Yu and Amdahl (2021) and Yu et al. (2022) investigated the motion response and energy absorption of the OO-STAR semi-submersible wind turbine colliding with 7500-ton service and large passing vessels under parked and typical operating conditions using the nonlinear finite element code USFOS. With an initial kinetic energy of 420 MJ, the platform exhibited significant displacements and rotations. In addition, the floating wind turbines were more resistant to ship collision impact than the fixed wind turbines.

Zong et al. (2023) studied the dynamic response and collision performance of the OC4 wind turbine struck by a vessel under combined wind–wave–mooring loads based on Star-CCM+ and ABAQUS. The time-domain results, including during and after collisions, are shown in Figure 9. It was found that the collision on the side of the turbine caused a more significant effect on the structural response of the wind turbine.

Yu et al. (2024) studied the collision impact between the 15 MW UMaine VolturnUS-S wind turbines and ships, including service operation vessels, multi-purpose vessels, and anchor-handling tug ships, using ABAQUS. The influence of collision speed, displacement, angle, and ship shapes was examined and discussed based on the internal stiffener arrangement.

Márquez et al. (2022) proposed a mechanical model (MM) composed of an NREL 5 MW wind turbine, an ITI Energy barge-type platform, and a ship to evaluate the collision impact between the ship and the FOWT. In addition, the influence of wall thickness, collision location, and impact energy on the dynamic response of the FOWT were parametrically analyzed. The data showed that the developed model MM could precisely investigate the structural response and collision impact of both structures, as shown in Figure 10.

Currently, research on collisions between floating wind turbines and ships remains limited and underdeveloped. In addition, research on collision behavior under extreme weather conditions is also inadequate. However, with the ongoing trend of installation in deep water, the number of floating wind turbines is expected to increase, increasing the risk of ship collisions. Therefore, future studies on ship collisions with floating wind turbines should receive more attention to enhance the operational safety of wind turbines in the presence of passing vessels.

Biehl (2004) investigated the collision resistance characteristics of monopile and tripod foundations for OWTs. The structural damage characteristics and energy dissipation curves of the monopile tripod foundation and the impact of vessel collision velocity on the results were elucidated and analyzed. Amdahl and Holmas (2011) analyzed the dynamic response of a jacket-supported wind turbine struck by a high-energy ship collision with 2 m/s impact speed. It was found that the water depth and jacket layout played an important role in the collapse mode. Ramberg (2011) analyzed the local buckling characteristics of the connection points between the jacket-supported wind turbines and US. The structural response of the wind turbine after collisions at various impact locations on the jacket was considered. Ding et al. (2014) studied the dynamic response of the FOWT subjected to the collision effect of a 5000-ton ship in the front point under various speeds based on the finite element code ABAQUS/Explicit. A significant inertial force was observed at the top of the tower, while the damage in the ship bow was relatively slight.

Travanca and Hao (2014) conducted a comprehensive numerical simulation of ship impacts on offshore jacket leg structures. The effects of impact velocity, bow stiffness, and pipe dimensions on ship collisions on the collision performance were also investigated. The impact velocity analysis with and without strain rate effects is shown in Figure 11. The vessel model comprised the range of 2000–5000-ton displacement.

Moulas et al. (2017) analyzed the collision damage that occurred when wind turbine foundations were struck by a 4000-ton ship. The monopile and jacket structures in shallow and deep water were adopted in that study. It indicated that collision energy, vessel height, and collision position were significant factors influencing the impacts between monopile OWTs and vessels. Prabowoputra et al. (2020) showed that OWT–ship collisions were affected by velocity, types of vessels, impact direction, collision angle, and so on. It used the factorial design method to reveal that velocity and collision direction were the most significant factors.

Ramberg (2011) studied the impact of collisions between monopile wind turbines and vessels. The correct selection of soil parameters and the consideration of soil–structure interaction had a significant impact on the collision performance. Sourne et al. (2015) investigated the dynamic response of the wind turbine to a collision with a ship to optimize the design of the main aspects. Particularly, the impact of foundation soil characteristics, like site conditions, on the dynamic response of the wind turbine was studied. In addition, two vessel drift speeds, 2 m/s and 5 m/s, were adopted to distinguish the impact energy absorbed by the foundation. Bela et al. (2015) studied the nacelle dynamics and crushing behavior of the monopile wind turbine subjected to a ship collision. The effects of multiple properties like ship location, soil stiffness, and deformability of the striking ship were also presented. Han et al. (2019) and Han et al. (2020) investigated the anti-collision performance of a 4 MW tripod wind turbine that used fenders subjected to the collision impact of the 2500-ton ship using ANSYS/LS-DYNA. In addition, the collision impact of the wind turbine from a 5000-ton ship was discussed. They also considered various material properties and thickness of the fender as well as the influence of soil–structure interaction. It was found that more effective anti-collision performance would be achieved when the thickness of the fender surpassed 1.1 m.

Zhang et al. (2014) studied the dynamic response of a FOWT to ship collision scenarios under multiple environmental conditions. It was found that the surge and pitch motions of the platform were dramatically affected in still water, as was the mooring system, while the yaw response would be increased under combined wind-wave conditions. Song et al. (2021) evaluated the dynamic response of a 5 MW monopile wind turbine to a collision with a 4600-ton vessel under various collision scenarios. The influences of aerodynamic damping, mean wind velocity, and ship impact speed were examined and compared using numerical and analytical methods. It demonstrated that the difference between those methods was 5% and 7% under impact speeds of 1 m/s and 3 m/s, respectively.

Kroondijk (2012) examined the collision performance of the jacket OWTs after a collision with a 160,000-ton oil tanker under loaded and unloaded conditions. Failures and overall structural damage to the jacket foundation were revealed. Dai et al. (2013) proposed a new framework to assess collision risks and key impact factors. The results indicated that low-speed collisions could potentially cause structural damage to wind turbines. In addition, seven collision scenarios, including head-on, maneuvering, and drifting collisions between the ship and wind turbine, were examined and compared. The results showed that the most significant damage would be caused if a ship directly struck the wind turbine. Hao and Liu (2017) investigated the foundation damage after a maximum collision force of a ship against a wind turbine. The impact factors, such as ship mass, velocity, and collision position, were compared.

A comprehensive evaluation of the anti-collision measures of various wind turbine platforms was conducted using the FEM tool LS-DYNA. The most optimum crashworthy performance was achieved by the jacket under low-energy collisions. Bela et al. (2017) conducted numerical simulations of vessel impacts on monopile foundation wind turbines. The effects of impact velocity, position, wind loads, and soil–structure interaction of dynamic responses of the tower structure for the wind turbine were studied. Gao and Zhang (2021) investigated the dynamic response of the jacket foundation for a 3 MW wind turbine after a collision with a 3000-ton cargo vessel. The impact of collision position and joint strength were distinguished and discussed. Liu et al. (2022) analyzed the collision performance of the wind turbine with a jacket foundation to identify the most vulnerable part and dangerous impaction point during a collision by vessels. The influence of impact points, collision directions, and angles were compared. The results showed that the eccentric impact would cause less severe local deformation than a centric collision impact, as depicted in Figure 12.

Mehreganian et al. (2024) studied two scenarios of blast phenomena and impact loads on wind turbines caused by collision with commercial ships. The impact of wind velocity, collision angle, and gravity loads have also been considered.

In conclusion, various studies have examined the significant impact factors on the dynamic response of the wind turbines subjected to a vessel collision. The parametrical analysis of the collision has a dramatic effect. However, the soil–structure interaction is so complicated that little research has addressed this component. In addition, the study of collision mechanics and structural response between wind turbines and ships is still insufficiently extensive.

Cezary Graczykowski et al. Yue et al. (2021a) introduced a torus-shaped adaptive inflatable structure featuring multiple distinct air chambers with mechanisms for rapid inflation and pressure release and validated the effectiveness of the device through finite element simulations of ship–OWT collisions. Ren and Ou (2009), Graczykowski and Holnicki-Szulc (2009) investigated the dynamic response of the typical 3 MW wind turbine with a monopile foundation damaged by the collision of a simplified 2000-ton class ship model using LS-DYNA. A novel conceptual steel sphere ring aluminum foam pad for wind turbines has been proposed. Additionally, a spherical layout of the crashworthy device could deflect the ship from the main wind turbine substructure, thus minimizing the impact of the damage from the ship. The dynamic responses of a wind turbine subjected to vessel collisions under varying vessel velocities, rubber material, and fender thickness were considered and optimized using the FEM tool LS-DYNA by Lee and Park (2012) (Ren and Ou, 2009). In addition, they proposed a framework to mitigate the impact on tripod-type wind turbine substructures struck by ships. The materials, such as natural rubber, neoprene, and composite, were selected to optimize the anti-collision effect. The result has shown that a rubber fender with a relatively lower thickness played a significant role in mitigating the collision impact from a ship. The impact between the ship and the tripod wind turbine substructure is complicated. Liu et al. (2015), Lee and Park (2012) proposed a novel crashworthy device comprising an outer steel shell and a rubber blanket to decrease the damage of monopile wind turbines by ship collision. It was able to significantly decrease the maximum collision force and nacelle acceleration for vessels with smaller initial kinetic energy. Ren et al. (2022), Liu et al. (2015) carried out an experimental study on the dynamic response of a 4 MW monopile wind turbine with a collision by a vessel. The effect of the crashworthy device on the anti-collision performance of the wind turbine was investigated. The protected device was capable of effectively reducing the top nacelle acceleration and the ship impact force.

Han et al. (2019) investigated the anti-collision performance of various fenders for wind turbine tripods during collisions with 2500-ton ships through ANSYS/LS-DYNA. The installation position and shape of the fender are shown in Figure 13. Four fender types made from two materials and combined in different configurations were evaluated based on collision force, energy absorption, maximum bending moment, and plastic strain. The results indicated that aluminum foam fenders performed best in protection, and the coefficient of restitution (COR) provided further insights into fender longevity.

Yue et al. (2021b) developed a fender for a tripod wind turbine to mitigate collision impact by ship. The effects of external diameter and various orders on the anti-collision impact on the wind turbine were examined using LS-DYNA. It was found that the structure of the first-order fractal pores played a significant role in absorbing more collision energy and enhancing the anti-collision performance of the fender. A literature review of analytical, numerical, and experimental methods for assessing the structural response of OWTs during ship collisions was presented by Ladeira et al. (2023b). Various energy transfer mechanisms and common procedures for evaluating wind load effects, soil–structure interactions, and hydrodynamic coupling were examined. Internal mechanics and hydrodynamic coupling schemes have also been surveyed, and the limitations of current models are discussed with recommendations for future research. Sun and Fang (2023) proposed a floating composite honeycomb anti-collision structure to mitigate the damage from ship–OWT high-energy collisions under typical scenarios. The anti-collision performance and dynamic response of a wind turbine with crashworthy structures were examined and compared to that without protection. The results showed that the structure was capable of absorbing 80% of the initial kinetic energy, dramatically decreasing the negative dynamic response of the wind turbine. Niklas et al. (2023) studied the collision characteristics between a 15 MW monopile wind turbine and a 6500-ton displacement supply offshore vessel. It was found that utilizing S355 grade steel could dramatically mitigate collision impact by 50% during a head-on sliding collision. Nie et al. (2024) proposed a novel fender employed on the monopile foundation wind turbine to mitigate the collision impact by ship. A viscoelastic fender with high initial stiffness achieved the most significant reductions in collision metrics, with maximum collision force decreasing by approximately 46.5% and acceleration by 54.8%.

Hirokawa et al. (2015) assessed the risk of mooring failure in FOWTs caused by collisions with drifting ships. A simulator was developed to replicate the collision process and drifting scenarios to establish a risk evaluation framework. The results indicated that the risk was primarily influenced by the potential for large ships to displace turbines, with additional risk depending on the arrangement of the wind farms. Copping et al. (2016) utilized the automatic identification system (AIS) system to mitigate the collision risk between ships and wind turbines, improving navigation safety. Mujeeb-Ahmed et al. (2018) developed a comprehensive and intelligible collision-risk method for OWTs exposed to ship collision impact through an AIS database. The statistical distribution of ship traffic and straightforward probabilistic methods were established to effectively predict the impact energy and collision risks for multiple types of vessels.

Kim et al. (2021) focused on the collision risks of wind turbine installation vessels (WTIVs) that are widely operated in offshore wind farms. A method for analyzing WTIV collision frequency was developed and compared with the existing methods. The study underscored the importance of considering the operational characteristics of WTIVs and discussed the implications for analyzing the collision frequency between wind turbines and vessels. The proposed method considered the design accidental load (DAL), while other methods only evaluated WTIVs as a fixed platform. Sen and Song (2021) examined the crashworthiness of the wind turbine against the collision by vessels based on the No.6 offshore wind farm project in Zhoushan Putuo, in eastern China. The data highlighted the demand for unified criteria so as to meet ocean challenges like channel distance, emergency management, and collision prevention. Xue and Qian (2023) proposed an anti-collision mechanism based on improved swarm intelligence. An adaptive brain storm optimization (ABSO) with variational inference-based expectation maximization was established to avoid collision impact. In addition, the algorithm precisely and effectively improved navigation safety near offshore wind farms by optimizing turning amplitudes and route distances in tests.

Although numerical methods have been investigated to mitigate the negative influence of ship collisions with wind turbines, such as installing fenders and adaptive devices on the wind turbines, there is still limited application to engineering practice. Additionally, methods to reduce collision-risk coefficients using computer algorithms remain underdeveloped due to the current measures only making differences after collision. Advanced technologies like automated warning systems and intelligent navigation prediction frameworks are still limited in anti-collision applications. Research on reducing collision risk factors between ships and wind turbines is becoming increasingly important with the rapid development of the wind industry.