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2025, 39(6)
:985-1000.
doi: 10.1007/s13344-025-0076-8
Abstract:
Underwater Gliders (UGs) have emerged as vital instruments in marine research, offering distinct advantages including low operational costs, extended range capabilities, and superior durability. Traditional UGs, however, face limitations due to their substantial size, weight, cost, and deployment complexity. Moreover, the conventional oil pump method for buoyancy adjustment exhibits slow response times, resulting in increased unsteady gliding depth ratios. These constraints limit their application in shallow water environments such as ports, coastal waters, and inland water bodies. This paper presents the TL-200, a small-sized underwater glider that incorporates an integrated buoyancy-driven and attitude adjustment mechanism. Through the implementation of an innovative buoyancy drive unit, the TL-200 achieves enhanced buoyancy regulation response while maintaining a simplified structure compared to conventional gliders. A dynamic model for the TL-200 was developed and validated through comparative analysis of numerical results and experimental data. Utilizing this dynamic model, motion simulations were conducted to examine the influence of metacentric height on motion parameters. Additionally, the study evaluated the gliding efficiency and energy consumption of the TL-200 under varying buoyancy adjustments. The findings demonstrate the effectiveness of this small-sized underwater glider’s integrated buoyancy-driven and attitude adjustment mechanism.
Underwater Gliders (UGs) have emerged as vital instruments in marine research, offering distinct advantages including low operational costs, extended range capabilities, and superior durability. Traditional UGs, however, face limitations due to their substantial size, weight, cost, and deployment complexity. Moreover, the conventional oil pump method for buoyancy adjustment exhibits slow response times, resulting in increased unsteady gliding depth ratios. These constraints limit their application in shallow water environments such as ports, coastal waters, and inland water bodies. This paper presents the TL-200, a small-sized underwater glider that incorporates an integrated buoyancy-driven and attitude adjustment mechanism. Through the implementation of an innovative buoyancy drive unit, the TL-200 achieves enhanced buoyancy regulation response while maintaining a simplified structure compared to conventional gliders. A dynamic model for the TL-200 was developed and validated through comparative analysis of numerical results and experimental data. Utilizing this dynamic model, motion simulations were conducted to examine the influence of metacentric height on motion parameters. Additionally, the study evaluated the gliding efficiency and energy consumption of the TL-200 under varying buoyancy adjustments. The findings demonstrate the effectiveness of this small-sized underwater glider’s integrated buoyancy-driven and attitude adjustment mechanism.
2025, 39(6)
:1001-1015.
doi: 10.1007/s13344-025-0077-7
Abstract:
Underwater cleaning robots face significant challenges from external disturbances, including waves, currents, surface contact forces, and reaction forces from cleaning equipment. These disturbances compromise trajectory-tracking accuracy and destabilize attachment force control, consequently diminishing cleaning performance. This paper presents a hybrid force/position control method to achieve simultaneous proper force and precise position control of underwater robots under disturbances. Following dynamics modeling and disturbance analysis, the study develops a pose controller utilizing active disturbance rejection control (ADRC) and a force controller employing an adaptive impedance method. An extended state observer (ESO) with gain fuzzy regulation observes and compensates for disturbances, ensuring precise trajectory tracking and stable adhesion force control. The disturbance estimate additionally facilitates online adjustment of the impedance controller’s desired force to maintain appropriate adhesion force. Simulation and experimental results validate that the proposed method substantially improves disturbance resistance and motion capabilities, enabling underwater cleaning operations with suitable contact force and high trajectory accuracy.
Underwater cleaning robots face significant challenges from external disturbances, including waves, currents, surface contact forces, and reaction forces from cleaning equipment. These disturbances compromise trajectory-tracking accuracy and destabilize attachment force control, consequently diminishing cleaning performance. This paper presents a hybrid force/position control method to achieve simultaneous proper force and precise position control of underwater robots under disturbances. Following dynamics modeling and disturbance analysis, the study develops a pose controller utilizing active disturbance rejection control (ADRC) and a force controller employing an adaptive impedance method. An extended state observer (ESO) with gain fuzzy regulation observes and compensates for disturbances, ensuring precise trajectory tracking and stable adhesion force control. The disturbance estimate additionally facilitates online adjustment of the impedance controller’s desired force to maintain appropriate adhesion force. Simulation and experimental results validate that the proposed method substantially improves disturbance resistance and motion capabilities, enabling underwater cleaning operations with suitable contact force and high trajectory accuracy.
2025, 39(6)
:1016-1027.
doi: 10.1007/s13344-025-0078-6
Abstract:
The impact force effect on launch platform motion response represents a critical safety consideration that requires thorough investigation prior to sea-launch implementation. This paper examines a self-designed semi-submersible launch platform comprising a box-shaped deck, six columns, and two pontoons, with sufficient structural stiffness to be analyzed as a rigid body. A proprietary code based on three-dimensional linear potential theory was developed for hydrodynamic analysis of the launching process. The Cummins equation was implemented to calculate platform responses under substantial impact force. The numerical results were validated through comparison with ANSYS/Aqwa commercial software for platform motion response in both launch and non-launch cases. Additionally, two model tests were conducted in a sea-keeping wave basin at a scale ratio of λ =1:40. The numerical results demonstrated good agreement with experimental data. Both numerical and experimental findings indicate that platform motion responses result from wave-induced effects and impact force/rocket weight effects, with the latter typically predominant. Numerical simulations revealed that in moderate sea states, maximum heave and pitch motions measure 0.6 m and 1°, respectively, suggesting the viability of sea-launch operations using the designed platform under these conditions.
The impact force effect on launch platform motion response represents a critical safety consideration that requires thorough investigation prior to sea-launch implementation. This paper examines a self-designed semi-submersible launch platform comprising a box-shaped deck, six columns, and two pontoons, with sufficient structural stiffness to be analyzed as a rigid body. A proprietary code based on three-dimensional linear potential theory was developed for hydrodynamic analysis of the launching process. The Cummins equation was implemented to calculate platform responses under substantial impact force. The numerical results were validated through comparison with ANSYS/Aqwa commercial software for platform motion response in both launch and non-launch cases. Additionally, two model tests were conducted in a sea-keeping wave basin at a scale ratio of λ =1:40. The numerical results demonstrated good agreement with experimental data. Both numerical and experimental findings indicate that platform motion responses result from wave-induced effects and impact force/rocket weight effects, with the latter typically predominant. Numerical simulations revealed that in moderate sea states, maximum heave and pitch motions measure 0.6 m and 1°, respectively, suggesting the viability of sea-launch operations using the designed platform under these conditions.
2025, 39(6)
:1028-1041.
doi: 10.1007/s13344-025-0079-5
Abstract:
Semi-submersible platforms operating in deep seas encounter complex environmental conditions, making experimental studies on their global performance essential for new platform designs. Model tests were conducted to examine the 6-DOF motion characteristics of a conceptual semi-submersible platform equipped with a hollow moonpool (SPHM). The experimental results indicate that heave motions of the SPHM demonstrate suboptimal performance, potentially due to the natural heave period coinciding with the predominant wave energy range in the South China Sea. Furthermore, parametric rolling was observed during both regular and irregular wave tests and analyzed through Mathieu’s equation. The analysis reveals that parametric rolling of the SPHM exhibits primarily low-frequency motion with substantial amplitudes, with its period matching the natural roll period. Notably, parametric rolling persists for only several natural roll periods of the platform, leading to considerable variance in roll motions.
Semi-submersible platforms operating in deep seas encounter complex environmental conditions, making experimental studies on their global performance essential for new platform designs. Model tests were conducted to examine the 6-DOF motion characteristics of a conceptual semi-submersible platform equipped with a hollow moonpool (SPHM). The experimental results indicate that heave motions of the SPHM demonstrate suboptimal performance, potentially due to the natural heave period coinciding with the predominant wave energy range in the South China Sea. Furthermore, parametric rolling was observed during both regular and irregular wave tests and analyzed through Mathieu’s equation. The analysis reveals that parametric rolling of the SPHM exhibits primarily low-frequency motion with substantial amplitudes, with its period matching the natural roll period. Notably, parametric rolling persists for only several natural roll periods of the platform, leading to considerable variance in roll motions.
2025, 39(6)
:1042-1053.
doi: 10.1007/s13344-025-0082-x
Abstract:
Sea ice exhibits complex mechanical properties, and no unified constitutive model currently exists. This study establishes an elastoplastic sea ice constitutive model based on non-ordinary state-based Peridynamics (PD) and the Tsai-Wu yield criterion, applying force state calculations to sea ice collisions while mitigating zero energy modes. A Fortran program implements the elastic-plastic constitutive equation of PD to simulate spherical ice-steel plate collisions. The program’s accuracy in simulating sea ice collisions is validated through comparison with finite element results. Using the established model, this study simulates collisions between vertical structures and layer ice, analyzing the effects of impact velocity, vertical structure size, and critical elongation on sea ice load. The findings demonstrate positive correlations between collision force and impact velocity, vertical structure size, and critical elongation. At high velocities, impact significantly affects collision force, primarily following a quadratic function, while vertical structure effects exhibit a linear relationship.
Sea ice exhibits complex mechanical properties, and no unified constitutive model currently exists. This study establishes an elastoplastic sea ice constitutive model based on non-ordinary state-based Peridynamics (PD) and the Tsai-Wu yield criterion, applying force state calculations to sea ice collisions while mitigating zero energy modes. A Fortran program implements the elastic-plastic constitutive equation of PD to simulate spherical ice-steel plate collisions. The program’s accuracy in simulating sea ice collisions is validated through comparison with finite element results. Using the established model, this study simulates collisions between vertical structures and layer ice, analyzing the effects of impact velocity, vertical structure size, and critical elongation on sea ice load. The findings demonstrate positive correlations between collision force and impact velocity, vertical structure size, and critical elongation. At high velocities, impact significantly affects collision force, primarily following a quadratic function, while vertical structure effects exhibit a linear relationship.
2025, 39(6)
:1054-1069.
doi: 10.1007/s13344-025-0083-9
Abstract:
This paper presents a multi-module oscillating water column (OWC) wave energy converter (WEC) array system, comprising seven interconnected OWC modules. The modules are connected by elastic ropes with clumped weights positioned at the ropes’ midpoints. Three distinct mooring systems are designed for this OWC array, and the impact of mooring configurations on the hydrodynamic responses of the OWCs and mooring tensions is thoroughly examined. Three-dimensional potential flow theory is applied to perform time domain analyses. The motion responses of representative modules, the tension of specific mooring lines, and the spacing between adjacent modules in the array system are investigated through a comprehensive coupled dynamic analysis in the time domain. Based on these analyses, recommendations are provided for the optimal mooring system configuration for the array system.
This paper presents a multi-module oscillating water column (OWC) wave energy converter (WEC) array system, comprising seven interconnected OWC modules. The modules are connected by elastic ropes with clumped weights positioned at the ropes’ midpoints. Three distinct mooring systems are designed for this OWC array, and the impact of mooring configurations on the hydrodynamic responses of the OWCs and mooring tensions is thoroughly examined. Three-dimensional potential flow theory is applied to perform time domain analyses. The motion responses of representative modules, the tension of specific mooring lines, and the spacing between adjacent modules in the array system are investigated through a comprehensive coupled dynamic analysis in the time domain. Based on these analyses, recommendations are provided for the optimal mooring system configuration for the array system.
2025, 39(6)
:1070-1082.
doi: 10.1007/s13344-025-0084-8
Abstract:
This paper presents a numerical investigation of nonlinear sloshing in a prismatic tank. A three-dimensional, two-phase flow model based on Cartesian grid is developed to simulate the phenomenon. The model solves incompressible Navier-Stokes equations, utilizing the fractional step method for velocity-pressure decoupling. The finite difference method discretizes spatial derivatives, with specific schemes implemented to enhance model robustness. Model validation involves simulating benchmark cases, and comparing wave profiles and pressure results with published experimental data and numerical findings. The model demonstrates robustness and accuracy in simulating violent sloshing. The validated model examines sloshing in a partially filled prismatic tank under combined surge and roll excitations. The study employs eight frequencies encompassing the natural frequencies of tank roll and surge motions. Roll motion excitation is fixed at 2°, while surge motion considers three excitation amplitudes (0.0 m, 0.01 m, and 0.02 m). Analysis reveals the effects of surge amplitude and excitation frequency on wave patterns, amplitudes, and pressure peaks. Results indicate the presence of multi-component waves, including transverse, diagonal, and longitudinal waves. Furthermore, the findings demonstrate a reduction in the natural frequency for surge motion through pressure peak analysis.
This paper presents a numerical investigation of nonlinear sloshing in a prismatic tank. A three-dimensional, two-phase flow model based on Cartesian grid is developed to simulate the phenomenon. The model solves incompressible Navier-Stokes equations, utilizing the fractional step method for velocity-pressure decoupling. The finite difference method discretizes spatial derivatives, with specific schemes implemented to enhance model robustness. Model validation involves simulating benchmark cases, and comparing wave profiles and pressure results with published experimental data and numerical findings. The model demonstrates robustness and accuracy in simulating violent sloshing. The validated model examines sloshing in a partially filled prismatic tank under combined surge and roll excitations. The study employs eight frequencies encompassing the natural frequencies of tank roll and surge motions. Roll motion excitation is fixed at 2°, while surge motion considers three excitation amplitudes (0.0 m, 0.01 m, and 0.02 m). Analysis reveals the effects of surge amplitude and excitation frequency on wave patterns, amplitudes, and pressure peaks. Results indicate the presence of multi-component waves, including transverse, diagonal, and longitudinal waves. Furthermore, the findings demonstrate a reduction in the natural frequency for surge motion through pressure peak analysis.
2025, 39(6)
:1083-1096.
doi: 10.1007/s13344-025-0085-7
Abstract:
The downstream region of the Yangtze River in China experiences tidal influences, with most tributary inlets regulated by hydraulic hubs that control water diversion and drainage. The cross-sectional characteristics of these rivers under intermittent diversion and drainage remain uncertain due to various boundary conditions, including tidal fluctuations from the Yangtze River, hydraulic hub operations, and tributary water levels. This study examines the Yanglintang River as a case study, utilizing a two-dimensional water-sediment numerical model to analyze the response of river cross-sections under varying diversion-to-drainage ratios. The findings demonstrate that river cross-sections transform from a regular trapezoidal shape to a pot-bottom configuration, achieving equilibrium within 2 to 3 years under the influence of water diversion and drainage. The operational duration of water diversion and drainage shows minimal impact on river cross-sectional morphology, with bed scouring reaching approximately 10 cm when the operational duration doubles. However, the flow rate of water diversion-drainage operations emerges as the primary factor controlling river cross-sectional morphology, resulting in bed scouring magnitude of approximately 1 m under doubled flow rate conditions.
The downstream region of the Yangtze River in China experiences tidal influences, with most tributary inlets regulated by hydraulic hubs that control water diversion and drainage. The cross-sectional characteristics of these rivers under intermittent diversion and drainage remain uncertain due to various boundary conditions, including tidal fluctuations from the Yangtze River, hydraulic hub operations, and tributary water levels. This study examines the Yanglintang River as a case study, utilizing a two-dimensional water-sediment numerical model to analyze the response of river cross-sections under varying diversion-to-drainage ratios. The findings demonstrate that river cross-sections transform from a regular trapezoidal shape to a pot-bottom configuration, achieving equilibrium within 2 to 3 years under the influence of water diversion and drainage. The operational duration of water diversion and drainage shows minimal impact on river cross-sectional morphology, with bed scouring reaching approximately 10 cm when the operational duration doubles. However, the flow rate of water diversion-drainage operations emerges as the primary factor controlling river cross-sectional morphology, resulting in bed scouring magnitude of approximately 1 m under doubled flow rate conditions.
2025, 39(6)
:1097-1111.
doi: 10.1007/s13344-025-0086-6
Abstract:
The integration of oscillating water columns (OWCs) with piles to create a dual-function OWC-pile breakwater presents an innovative approach for harbor construction and coastline protection while enabling wave energy utilization. Local scour significantly impacts foundation safety and is crucial for structural design. This study examines wave-induced local scour at a dual-function OWC-pile breakwater through experimental methods. A high-resolution laser scanner tracked the development of 3D local scour profiles at various time intervals under regular wave conditions. The analysis focused on key parameters including scour-hole development time scale, dimensions, reflection and transmission coefficients, and energy extraction efficiency during scour evolution. The integration of OWCs substantially increased the equilibrium scour depth compared to conventional pile breakwaters, potentially affecting foundation stability. The scour profile development showed minimal impact on wave energy conversion efficiency. Wave transmission and reflection remained largely unaffected by scour holes, as verified through a semi-theoretical wave scattering model for pile breakwaters. An existing time-scale formula for predicting scour depth onset in isolated circular piles under current action demonstrated reasonable accuracy in this application. The study examines the mechanisms behind increased equilibrium scour depth due to OWCs and proposes design recommendations to mitigate scour-hole depth increases.
The integration of oscillating water columns (OWCs) with piles to create a dual-function OWC-pile breakwater presents an innovative approach for harbor construction and coastline protection while enabling wave energy utilization. Local scour significantly impacts foundation safety and is crucial for structural design. This study examines wave-induced local scour at a dual-function OWC-pile breakwater through experimental methods. A high-resolution laser scanner tracked the development of 3D local scour profiles at various time intervals under regular wave conditions. The analysis focused on key parameters including scour-hole development time scale, dimensions, reflection and transmission coefficients, and energy extraction efficiency during scour evolution. The integration of OWCs substantially increased the equilibrium scour depth compared to conventional pile breakwaters, potentially affecting foundation stability. The scour profile development showed minimal impact on wave energy conversion efficiency. Wave transmission and reflection remained largely unaffected by scour holes, as verified through a semi-theoretical wave scattering model for pile breakwaters. An existing time-scale formula for predicting scour depth onset in isolated circular piles under current action demonstrated reasonable accuracy in this application. The study examines the mechanisms behind increased equilibrium scour depth due to OWCs and proposes design recommendations to mitigate scour-hole depth increases.
2025, 39(6)
:1112-1125.
doi: 10.1007/s13344-025-0087-5
Abstract:
This study examines the structural responses of a novel articulated foundation wind turbine with compliant structural design under offshore winds, waves, and seismic events. A numerical simulation analysis framework, ADRT (Articulated Foundation Offshore Wind Turbine Dynamic Analysis and Response Prediction Tool), has been developed and validated through benchmark studies with established numerical tools, demonstrating strong correlation. The research conducts dynamic response analysis of the Articulated Foundation Offshore Wind Turbine (AFOWT) system under various seismic scenarios. Analysis reveals that response amplitude increases proportionally with seismic intensity. When wind and seismic forces act simultaneously, the system’s response amplitude perpendicular to the rotor plane decreases compared with isolated seismic action, attributed to aerodynamic damping effects, except for blade deformation response. During emergency braking shutdown operations triggered by seismic excitation, the structural seismic response exceeds design safety thresholds during the shutdown feathering process, indicating that emergency shutdown procedures do not effectively mitigate the system’s structural response.
This study examines the structural responses of a novel articulated foundation wind turbine with compliant structural design under offshore winds, waves, and seismic events. A numerical simulation analysis framework, ADRT (Articulated Foundation Offshore Wind Turbine Dynamic Analysis and Response Prediction Tool), has been developed and validated through benchmark studies with established numerical tools, demonstrating strong correlation. The research conducts dynamic response analysis of the Articulated Foundation Offshore Wind Turbine (AFOWT) system under various seismic scenarios. Analysis reveals that response amplitude increases proportionally with seismic intensity. When wind and seismic forces act simultaneously, the system’s response amplitude perpendicular to the rotor plane decreases compared with isolated seismic action, attributed to aerodynamic damping effects, except for blade deformation response. During emergency braking shutdown operations triggered by seismic excitation, the structural seismic response exceeds design safety thresholds during the shutdown feathering process, indicating that emergency shutdown procedures do not effectively mitigate the system’s structural response.
2025, 39(6)
:1126-1138.
doi: 10.1007/s13344-025-0088-4
Abstract:
The numerical simulation and analysis of natural gas hydrates with heat and mass transfer are essential for identifying and predicting reservoir states during dissociation and seepage processes. In specific cases, the transported substance may undergo phase transitions between solid, liquid, or gas states during dissociation and hydration processes. To effectively predict hydrate dissociation performance influenced by multi-field coupling processes, this study proposes a novel bond-based peridynamic coupled finite difference model that accounts for gas-liquid two-phase seepage behavior. The developed peridynamic (PD) model simulates hydrate dissociation reactions accompanied by gas-liquid seepage, mass transfer, and heat transfer phenomena. The formulation demonstrates strong agreement with established analytical solutions for one-dimensional problems and finite element transient solutions for two-dimensional problems in the literature, validating the accuracy and reliability of the newly constructed model. This research presents an innovative approach to simulate heat transport and multiphase flow phenomena associated with hydrate dissociation.
The numerical simulation and analysis of natural gas hydrates with heat and mass transfer are essential for identifying and predicting reservoir states during dissociation and seepage processes. In specific cases, the transported substance may undergo phase transitions between solid, liquid, or gas states during dissociation and hydration processes. To effectively predict hydrate dissociation performance influenced by multi-field coupling processes, this study proposes a novel bond-based peridynamic coupled finite difference model that accounts for gas-liquid two-phase seepage behavior. The developed peridynamic (PD) model simulates hydrate dissociation reactions accompanied by gas-liquid seepage, mass transfer, and heat transfer phenomena. The formulation demonstrates strong agreement with established analytical solutions for one-dimensional problems and finite element transient solutions for two-dimensional problems in the literature, validating the accuracy and reliability of the newly constructed model. This research presents an innovative approach to simulate heat transport and multiphase flow phenomena associated with hydrate dissociation.
2025, 39(6)
:1139-1150.
doi: 10.1007/s13344-025-0090-x
Abstract:
A coupled tide-surge-wave model was established to analyze the impacts of radial sand ridges on storm surges in the South Yellow Sea. Numerical topography experiments were designed on the basis of multiple well-verified types of extreme weather events. The findings demonstrated that the radial sand ridges (RSRs) generally enhanced tidal levels, current velocities, and significant wave heights in the affected area. The nonlinear effects of shallow water in the radial sand ridge area can induce large tide ranges. A unique seabed can cause an increase in current speed from the open sea to the nearshore. Another impact is that subaqueous ridges can result in shallow water conditions, and the degree of depth-induced wave breaking significantly varies. Compared with those in the northern and southern radial sand ridge areas, the tidal levels, current speeds, and wave heights in the middle radial sand ridge area were the highest, which can cause more severe storm surge disasters. Additionally, the wave radiation stress varied obviously under the action of fan-shaped sand ridges. Thus, it is necessary to consider wave-current interactions when modeling storm surges in sand ridges.
A coupled tide-surge-wave model was established to analyze the impacts of radial sand ridges on storm surges in the South Yellow Sea. Numerical topography experiments were designed on the basis of multiple well-verified types of extreme weather events. The findings demonstrated that the radial sand ridges (RSRs) generally enhanced tidal levels, current velocities, and significant wave heights in the affected area. The nonlinear effects of shallow water in the radial sand ridge area can induce large tide ranges. A unique seabed can cause an increase in current speed from the open sea to the nearshore. Another impact is that subaqueous ridges can result in shallow water conditions, and the degree of depth-induced wave breaking significantly varies. Compared with those in the northern and southern radial sand ridge areas, the tidal levels, current speeds, and wave heights in the middle radial sand ridge area were the highest, which can cause more severe storm surge disasters. Additionally, the wave radiation stress varied obviously under the action of fan-shaped sand ridges. Thus, it is necessary to consider wave-current interactions when modeling storm surges in sand ridges.
2025, 39(6)
:1151-1161.
doi: 10.1007/s13344-025-0091-9
Abstract:
This paper introduces a three-dimensional concave hexagonal honeycomb structure (3D-CHH) with enhanced impact resistance, developed from a two-dimensional concave hexagonal honeycomb structure (2D-CHH), to advance the application of metamaterials in ship protection structures. Both structures were fabricated using additive manufacturing techniques and subjected to quasi-static compression testing to evaluate their deformation modes and energy-absorbing capabilities. Combined experimental and numerical simulation results revealed that 2D-CHH exhibited a “<” mode, while 3D-CHH demonstrated an inward concave “I” mode, with 3D-CHH showing superior negative Poisson’s ratio characteristics. The deformation behavior of both structures progresses through four distinct phases: elastic zone, stress plateau zone, plateau stress enhancement zone, and densification zone characterized by rapid stress elevation. The 3D-CHH structure exhibits superior energy absorption compared with both 2D-CHH and conventional honeycomb structures, achieving nearly twice the specific energy absorption of 2D-CHH. Additionally, 3D-CHH shows an 8.4% improvement in energy absorption efficiency compared with 2D-CHH. The enhanced negative Poisson’s ratio effect and superior energy absorption properties of 3D-CHH enable effective ship protection while reducing structural weight.
This paper introduces a three-dimensional concave hexagonal honeycomb structure (3D-CHH) with enhanced impact resistance, developed from a two-dimensional concave hexagonal honeycomb structure (2D-CHH), to advance the application of metamaterials in ship protection structures. Both structures were fabricated using additive manufacturing techniques and subjected to quasi-static compression testing to evaluate their deformation modes and energy-absorbing capabilities. Combined experimental and numerical simulation results revealed that 2D-CHH exhibited a “<” mode, while 3D-CHH demonstrated an inward concave “I” mode, with 3D-CHH showing superior negative Poisson’s ratio characteristics. The deformation behavior of both structures progresses through four distinct phases: elastic zone, stress plateau zone, plateau stress enhancement zone, and densification zone characterized by rapid stress elevation. The 3D-CHH structure exhibits superior energy absorption compared with both 2D-CHH and conventional honeycomb structures, achieving nearly twice the specific energy absorption of 2D-CHH. Additionally, 3D-CHH shows an 8.4% improvement in energy absorption efficiency compared with 2D-CHH. The enhanced negative Poisson’s ratio effect and superior energy absorption properties of 3D-CHH enable effective ship protection while reducing structural weight.
2025, 39(6)
:1162-1175.
doi: 10.1007/s13344-025-0092-8
Abstract:
Suction bucket jacket foundations exhibit considerable potential for implementation in deep-sea offshore wind power projects. To address water film formation resulting from negative pressure penetration during construction, certain suction bucket jacket foundation projects implement grouting techniques to ensure adequate bearing capacity. This study conducted a large-scale suction bucket foundation grouting model experiment to examine grout flow characteristics and specific phenomena under various grouting pipeline configurations. Comparative analyses of grouting efficiency and quality across different pipeline layouts identified critical influencing factors and their impact on grouting performance. The results demonstrate that the number of grout outlets should be maintained within an optimal range: insufficient outlets enhance the indentation effect and decrease fill efficiency, while excessive outlets necessitate precise spacing for effective distribution. Additionally, grout outlets should be uniformly arranged to reduce segregation and enhance overall grouting quality. This study’s findings provide a scientific foundation for optimizing grouting design in suction bucket jacket foundations, with substantial implications for engineering applications.
Suction bucket jacket foundations exhibit considerable potential for implementation in deep-sea offshore wind power projects. To address water film formation resulting from negative pressure penetration during construction, certain suction bucket jacket foundation projects implement grouting techniques to ensure adequate bearing capacity. This study conducted a large-scale suction bucket foundation grouting model experiment to examine grout flow characteristics and specific phenomena under various grouting pipeline configurations. Comparative analyses of grouting efficiency and quality across different pipeline layouts identified critical influencing factors and their impact on grouting performance. The results demonstrate that the number of grout outlets should be maintained within an optimal range: insufficient outlets enhance the indentation effect and decrease fill efficiency, while excessive outlets necessitate precise spacing for effective distribution. Additionally, grout outlets should be uniformly arranged to reduce segregation and enhance overall grouting quality. This study’s findings provide a scientific foundation for optimizing grouting design in suction bucket jacket foundations, with substantial implications for engineering applications.
2025, 39(6)
:1176-1188.
doi: 10.1007/s13344-025-0093-7
Abstract:
Rubble mound breakwaters, a prevalent type of sloping breakwater structure, are extensively employed in port and coastal infrastructure projects. Under soft soil foundation conditions, the process of squeezing silt by riprap is implemented to enhance bearing capacity through soft soil replacement and compaction. However, predicting the depth law of squeezing silt by riprap and understanding its mechanism remain significant engineering design challenges. This study employs particle flow code (PFC) based on the discrete element method to simulate the squeezing silt process by riprap, examining variations in depth law under different geological conditions and its mechanical characteristics. Through calibration of the PFC model’s meso-parameters via macro-experiments, the study analyzes the effects of riprap size, drop height, and soft soil properties on the depth law of squeezing silt. Findings demonstrate that riprap drop height and soft soil thickness substantially influence the depth, while appropriate calibration of meso-parameters enhances simulation accuracy. This research contributes theoretical and practical guidance for optimizing rubble mound breakwater design, understanding squeezing silt mechanisms, construction practices, and riprap quantity estimation.
Rubble mound breakwaters, a prevalent type of sloping breakwater structure, are extensively employed in port and coastal infrastructure projects. Under soft soil foundation conditions, the process of squeezing silt by riprap is implemented to enhance bearing capacity through soft soil replacement and compaction. However, predicting the depth law of squeezing silt by riprap and understanding its mechanism remain significant engineering design challenges. This study employs particle flow code (PFC) based on the discrete element method to simulate the squeezing silt process by riprap, examining variations in depth law under different geological conditions and its mechanical characteristics. Through calibration of the PFC model’s meso-parameters via macro-experiments, the study analyzes the effects of riprap size, drop height, and soft soil properties on the depth law of squeezing silt. Findings demonstrate that riprap drop height and soft soil thickness substantially influence the depth, while appropriate calibration of meso-parameters enhances simulation accuracy. This research contributes theoretical and practical guidance for optimizing rubble mound breakwater design, understanding squeezing silt mechanisms, construction practices, and riprap quantity estimation.
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Current Issue
- Volume 39
- Issue 6
- December 2025
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CHINA ASSOCIATION FOR SCIENCE AND TECHNOLOGY
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Chinese Ocean Engineering Society （COES）
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Nanjing Hydraulic Research Institute
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