The rapid expansion of offshore renewable energy installations, such as wind farms, tidal turbines, and wave energy converters, has increased concerns regarding ship collision risks. As maritime traffic intensifies, understanding the impact of vessel collisions on these structures is crucial for ensuring operational safety and structural resilience. This review thoroughly analyses ship collisions with offshore renewable structures, concentrating on risk assessment methodologies, structural response mechanisms, and mitigation strategies. Various numerical and experimental approaches for impact modelling are examined, alongside advanced materials and design innovations aimed at improving collision resistance. Furthermore, current regulatory frameworks and emerging technologies, including artificial intelligence (AI)-driven collision avoidance systems, are discussed. The review identifies key challenges and future research directions, emphasising the need for integrated monitoring systems and predictive modelling to enhance offshore energy infrastructure safety. This study provides a foundation for engineers, policymakers, and researchers to develop more resilient offshore renewable energy solutions in response to increasing maritime activity.

Through a series of tests and numerical analyses, this study examines the axial compression behaviour of stub cold-formed steel (CFS) lipped channels subjected to simulated local web corrosion. In the tests, the random nature of local corrosion is simplified as a circumscribed rectangular defect with a constant corrosion depth. Corrosion degradation alters the load transfer path, causing stress concentration in the plate and promoting the early onset of local buckling, thereby reducing the ultimate resistance. As corrosion spreads increase, the ultimate resistance decreases significantly. A numerical study was conducted to assess the randomness of corrosion spread and location for subsequent parametric analysis. Finally, an equivalent thickness was introduced to account for the impact of local corrosion on the local buckling stress. The modified calculation method, validated by both experimental and numerical results, provides a practical, adaptable tool for predicting the ultimate resistance of stub CFS-lipped channels with simulated local web corrosion. This approach offers engineering implications by enabling corrosion-aware design and assessment of CFS members under service-degradation conditions.

This study investigates the vibration characteristics of butt-welded plate structures influenced by weldinginduced residual stress and deformation. A theoretical model incorporating the corrected elastic modulus is developed, along with a numerical model accounting for welding parameters. Both models were validated against experimental data. An empirical expression combined with sensitivity analysis is then proposed to analyze the influence of various welding parameters, with its reliability confirmed through experimental and theoretical comparisons. The experimental results indicate that the vibration characteristics of the plate structure are influenced by welding residual stress and deformation, with a 13.7 % decrease in the first-order natural frequency. The developed theoretical and numerical models achieve high prediction accuracy, with errors of 2.2 % and 2.6 %, respectively. Compared with the undeveloped model, the corrected model improved prediction accuracy by 11.5 % and 11.1 %. Sensitivity analysis reveals that welding speed is the dominant factor, while welding current becomes more significant when interaction effects are considered. Overall, this work provides a thorough framework for understanding and controlling the vibration properties of welded structures.

The ultrasonic anti-icing and de-icing system applies an electrical field to the ship’s surface to weaken the adhesion between the ice layer and the steel plates, while using ultrasonic vibration to generate longitudinal shear forces that break the remaining adhesion, thereby achieving effective de-icing. This study employs the control variable method to examine how different vibration frequencies and configurations of ultrasonic vibrators (“de-icing formations”) impact the adhesion characteristics of the ice layer covering the hull steel plates. Due to the lack of existing experimental instruments for measuring the adhesion force of ship icing, we designed an intelligent device to test the adhesion force between the ship and the ice layer. This device incorporates high-precision sensors and an advanced data acquisition system, enabling real-time measurement and recording of adhesion force data between icing and the hull steel plates. Using the newly developed JUST flat plate adhesion force testing system, this study evaluates how various distribution strategies of ultrasonic vibrators influence the ice adhesion force. Furthermore, the experiment investigates the de-icing efficiency of ultrasonic vibrators with the same number of but different “de-icing formations” and vibration frequencies under identical conditions of ice thickness, time, and excitation current, and provides a detailed analysis of the variation in ice adhesion force. These results clarify the mechanism by which the ultrasonic system manages the adhesion force of ship icing. This research not only introduces new ideas and methods for ship anti-icing and de-icing technology but also offers a scientific basis for enhancing navigation safety and operational efficiency in icy conditions.

As passenger-comfort requirements in the cruise industry continue to rise, lightweight, high-strength sandwich panels with enhanced acoustic performance have attracted considerable attention. In this study, a C-shaped sandwich panel (C-SSP) is proposed to improve the cabin sound-insulation characteristics of cruise ships. The conventional stiffened plate is replaced with the C-SSP under an equal-mass constraint, and the superiority of the new configuration is demonstrated through comparative analysis. A theoretical sound-insulation model for the CSSP is developed by combining the space-harmonic method with the principle of virtual work; its predictions show good agreement with numerical simulations, confirming the model's validity. Sensitivity analyses reveal that the elastic modulus of the face sheets and a moderate panel spacing exert the greatest influence on the cabin's acoustic performance. Moreover, the sound-transmission loss increases as the stiffener spacing and stiffener thickness decrease. To assess ship-scale applicability, a hybrid FE-SEA (finite element-statistical energy analysis) model of a cruise-ship cabin is built in VA One, and the feasibility of substituting the original deck with C-SSPs is investigated. Overall, the C-SSP achieves an improved balance between structural mass and acoustic insulation, offering a practical solution for next-generation cruise-cabin design.

The demand for sustainable ship design has driven the use of high-strength steel to reduce structural weight, although this introduces buckling challenges due to unchanged elastic properties. Supported by the ISSC 2025 Ultimate Strength Committee, this study evaluated the ability of numerical simulations to predict the nonlinear response and ultimate strength of stiffened panels subjected to transverse compression. The benchmark consisted of full-scale blinded experimental tests that were conducted in parallel using a deck-like structure with thin plating prone to elastic buckling. The finite element models produced by participating researchers were compared, focusing on the complete end-shortening curve rather than just ultimate strength. Despite identical input geometry and minimal modeling guidance, results varied widely, revealing the significant influence of user-defined assumptions. The inclusion of additional data on material properties in the second study phase led to greater result dispersion due to the different strategies adopted for the hardening model. Key variability sources included the modeling of initial imperfections, material constitutive laws, and residual stresses from welding. The study highlights the need for consistent modeling and improved experimental data collection, particularly regarding boundary conditions and residual stress effects. While including welding stresses improved stiffness predictions, uncertainty in boundary behavior limited the assessment of ultimate strength impacts. The study also evaluated compliance with classification society rules (e.g., CSR, DNV, UR-S35), offering insights into how nonlinear numerical analyses complement or challenge regulatory frameworks based on closed-form expressions. Recommendations are made for improving simulation reliability and result validation.

Real-time full-field stress monitoring is pivotal for assuring the structural integrity of Floating Nuclear Power Plants operating in harsh marine environments. However, the intricate hull topology and extremely sparse sensor configurations pose significant challenges for accurate field reconstruction. This paper proposes a Physics-Informed Gated Spatial Graph Transformer (PI-GSGT) model. The model incorporates multi-source positional encoding to capture global topology and geometric distribution. Through a dual-path evolution block that integrates a Graph Attention Network and a Sensor Cross-Attention mechanism, it jointly addresses the local continuity and global coordination of the mechanical field. By embedding a graph Laplacian smoothing term into the composite loss function, the model achieves a seamless integration of data-driven accuracy and mechanics-based prior constraints. The experimental results demonstrate that PI-GSGT achieves a reconstruction consistency (the coefficient of determination R2 reached 0.9966) for the von Mises equivalent stress field under multiple load conditions, significantly outperforming baseline graph neural networks. Under extreme conditions involving 20% noise contamination or 50% sensor failures, the model still exhibits robust performance (R2>0.91). Attention weight analysis further confirms that its reconstruction logic aligns with fundamental principles of the principles of elasticity, providing reliable technical support for the digital twin operation and maintenance of the FNPP.

This paper investigates the structural behaviour of small-diameter steel pipes with dents subjected to four-point bending. Experiments are conducted to determine the influence of small pre-induced dents on the pipes’ bending performance and failure characteristics. The tests involve measuring the load-displacement response and identifying the critical failure modes. Numerical simulations using the finite element method are performed to model the bending process and validate the experimental results. The simulations provide insights into the stress distribution and deformation patterns of the dented pipes. The comparison between experimental and numerical results demonstrates a good correlation, indicating the accuracy of the simulation model. This research contributes to understanding the effects of dents on the structural integrity of steel pipes and offers a validated approach for future predictive modelling.

This study investigates the repair effect on the ultimate strength of the pitting stiffened plate. A series of experiments were performed, as the pitting stiffened plates were strengthened by CFRP (Carbon Fiber Reinforced Polymer) and a combination of CFRP and GFRP (Glass Fiber Reinforced Polymer), to examine the repair factors including CFRP area, repair position and combination of CFRP and GFRP fillers. The CFRP repair was verified to be effective on the ultimate strength, comparing the results of the pitted stiffened plate without repair. It is found that with 300 mm*1200 mm CFRP repair, the ultimate was increased by 14 %. The repair with 250 mm*450 mm on the surface of the pitting surface increase the ultimate strength by 8 %, while the repair on the surface of the non-pitting surface by 5 %, and the GFRP filler + CFRP increase the ultimate strength by 11 %.

With transportation's rapid growth, ship-bridge collisions occur frequently, causing substantial losses. Ship-bridge anticollision facilities should not only protect the structural integrity of bridges but also minimise ship damage. This paper designs a novel ship-bridge anti-collision device based on a trapezoidal foam-filled composite sandwich structure. Using the finite element software LS-DYNA, a ship-anti-collision device-bridge collision model was established, taking into account pile-water-soil coupling. The study investigates the selection of box materials, filling materials and wall thickness for the novel anti-collision device. By analysing the damage characteristics of the ship, anti-collision device and pier under typical collision loads, the optimal material properties were determined. The impact resistance of the optimised device was evaluated under different ship speeds and collision angles, demonstrating that the novel anti-collision device exhibits excellent buffering and energy absorption, effectively reducing the peak collision force, extending the collision duration and reducing damage to the ship's bow structure.

A trimaran structure damage identification method based on machine learning is proposed. In the damage identification method, the wavelet transform and an improved adaptive threshold function are combined to realise wavelet filtering (WF), and the structural curvature difference based on fractal box dimension is used as a critical index to train a back-propagation (BP) neural network for identifying the damage degree and location. The improved particle swarm optimisation (IPSO) is adopted to develop an IPSO-WF-BP strategy for synergistically optimising the BP neural network and the wavelet filter. In addition, to make the local structure response simulation more realistic, the monitoring load data from a trimaran model test are extracted and combined with the finite element method to simulate multiple damage occurrences under different hull deformations. Comparative analysis has finally demonstrated the reliability of the IPSO-WF-BP model in different wave environments and noise signals. This damage identification method will provide technical support for auxiliary decision-making and damage diagnosis of intelligent trimarans.

The impact responses of welded aluminium plates made from AA6061-T6 are systematically examined through experimental testing and numerical simulation, with a focus on the softening phenomena in the heat-affected zone (HAZ). Specimens with different numbers of welds and impact points are designed to clarify how HAZ softening affects damage features. Hardness and tensile tests are conducted to identify the material properties near the welds, supplying critical data for the numerical models. Finite element simulations of the impact tests are performed, explicitly considering the softening zones near the welds, to analyze damage behavior under various impact scenarios. Additionally, conventional simplified modelling methods for HAZ softening are evaluated and systematically compared to thoroughly assess the accuracy and applicability of different numerical modelling techniques for welded aluminium plates subjected to impact loading.

The domain of maritime engineering is continually evolving with a focus on optimizing the performance and safety of ships and offshore structures [...]

The long-term responses of offshore wind turbines (OWTs) are critical in the design phase, where precise assessments ensure structural reliability and operational efficiency. The environmental contour method (ECM) enables efficient analysis of design responses by focusing on a selected set of critical environmental conditions that predominantly drive long-term extreme responses. Despite its extensive use in offshore engineering, ECM’s application in the structural design and strength assessment of OWTs remains underexplored. This study offers a comprehensive overview of the utilization of ECM in the context of OWT design, incorporating a bibliometric analysis of publications from the Web of Science to identify research trends and key topics. The analysis highlights diverse approaches for estimating long-term extreme responses and constructing environmental contours using statistical distributions. Additionally, the study explores the application of ECM and its modified versions in the design and strength assessment of OWTs. Challenges and opportunities associated with ECM implementation in OWTs are critically analyzed, providing insights into ECM’s potential for enhancing the efficiency and reliability of OWT structural design.

Offshore platforms need to be made, from the start of their construction, to withstand the extreme environmental conditions they will be facing. This study investigates the welding-induced residual stress and distortion in a Y-shaped tubular joint extracted from an offshore wind turbine jacket substructure. While similar joints are commonly used in offshore platforms, their welding behavior remains underexplored in the existing literature. The joint configuration is representative of critical load-bearing connections commonly used in offshore platforms exposed to harsh marine environments. A finite element model has been developed to simulate the welding process in a typical offshore tubular joint through thermal and mechanical simulation. Validation of the model has been achieved with results against reference experimental data, with temperature and distortion errors of 3.9 and 5.3%, respectively. Residual stress and distortions were analyzed along predefined paths in vertical, transverse, and longitudinal directions. A mesh sensitivity study was conducted to balance computational efficiency and result accuracy. Furthermore, clamped and free displacement boundary conditions are analyzed, demonstrating reduced deformation and stress for the second case.

This comprehensive review explores the application and impact of digital twin (DT) technology in bolstering the reliability of Floating Offshore Wind Turbines (FOWTs) and their supporting platforms. Within the burgeoning domain of offshore wind energy, this study contextualises the need for heightened reliability measures in FOWTs and elucidates how DT technology serves as a transformative tool to address these concerns. Analysing the existing scholarly literature, the review encompasses insights into the historical reliability landscape, DT deployment methodologies, and their influence on FOWT structures. Findings underscore the pivotal role of DT technology in enhancing FOWT reliability through real-time monitoring and predictive maintenance strategies, resulting in improved operational efficiency and reduced downtime. Highlighting the significance of DT technology as a potent mechanism for fortifying FOWT reliability, the review emphasises its potential to foster a robust operational framework while acknowledging the necessity for continued research to address technical intricacies and regulatory considerations in its integration within offshore wind energy systems. Challenges and opportunities related to the integration of DT technology in FOWTs are thoroughly analysed, providing valuable insights into the role of DTs in optimising FOWT reliability and performance, thereby offering a foundation for future research and industry implementation.

This review explores the recent advancements in welding techniques for aluminum plates utilized in ships and offshore structures, with a particular focus on minimizing weld-induced deformation and residual stress to improve structural performance. Given the critical role of welding in the construction and repair of marine structures, understanding the influence of these factors is paramount. This article synthesizes current research findings, evaluates the effectiveness of various welding methods, and highlights innovative approaches to reduce adverse effects. Through a comprehensive analysis of experimental and simulation studies, this review identifies key strategies for optimizing welding processes, thereby contributing to the durability and integrity of marine structures. This synthesis not only highlights successful strategies for optimizing welding processes but also offers guidance for researchers and practitioners in the field. This review also identifies previously unaddressed gaps in the literature, particularly focusing on the underexplored interactions between specific welding parameters and the long-term durability of marine structures, offering new perspectives and directions for future research. It delineates critical challenges faced in the welding of aluminum alloys for marine applications and offers targeted suggestions to address these issues, thereby paving the way for advancements in welding practices and technology. The findings aim to guide researchers and industry practitioners in selecting and developing welding techniques that ensure the safety, reliability, and longevity of marine infrastructure.

A subsea pipeline (also known as an offshore pipeline or submarine pipeline) is a pipeline that is laid on the seabed or inside a specially constructed trench [...]

The carrying capacity of pipes with initial dents under lateral bending is studied experimentally in the present work. Several factors of the initial dent are taken into consideration, namely the shape, size, position and depth of the dent. In the experiment, three-point bending tests on the scaled pipe specimens are performed in two steps. In the first step, the initial dent is introduced onto the pipe, with certain combinations of factors. Then in the second step, the residual carrying capacity of pipes with initial dents is obtained by lateral bending tests. The most severe situation is identified out in terms of the shape, size and position of initial dents. Finally, the relationship between the residual bending carrying capacity and initial dent depth is concluded.

An assessment is made of the stress distribution and the hydrodynamic response of the preliminary structural design of the tension leg platform of a 10 MW wind turbine. The platform supporting a 10 MW turbine is modelled and analysed by the finite element method. The stress distribution of the platform is determined in still water with the turbine at above-rated conditions, and the response of the tension leg platform is estimated in the time domain. The results of the time domain analysis show reasonable agreement between the present results and the available data. To check the design stiffener dimensions, span, and spacing against stress distribution, classification societies' recommendations are used. The results of the stress distribution analysis indicate that the critical locations of the platform are the interaction of the lower columns with the upper columns and the connection of the tower of the turbine.