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2025, 39(1)
:1-12.
doi: 10.1007/s13344-025-0001-1
Abstract:
The influences of different factors, including whether the transverse frames are actually built, longitudinal and transverse welding residual stresses, and unloaded edge boundaries, on the ultimate strength and failure mode of a real hull bottom full-scale stiffened plate under axial compression and lateral pressure are investigated via numerical analysis. Result shows that the failure mode of the stiffened plate under axial compression is the tripping of the stiffeners. Whether transverse frames are built has little effect on the ultimate strength of the stiffened plate under axial compression, which can be replaced by the degree of freedom constraint. However, when lateral pressure is present, the transverse frame cannot be simply replaced by a free-degree constraint. The longitudinal residual stress has a greater effect on the ultimate strength, whereas the effect of the transverse residual stress is smaller. Stronger unloaded edge boundary conditions can slightly enhance the stiffness and ultimate strength of the stiffened plate. Under combined axial compression and lateral pressure, the failure mode of stiffened plates changes from the tripping of stiffeners to beam-column failure, as the lateral pressure increases. The ability of stiffened plates in which transverse frames are actually built out to resist beam-column shape deformation becomes weaker with lower ultimate strength. Stronger unloaded edge boundary conditions can improve the ability of stiffened plates to resist beam-column deformation and increase the ultimate strength.
The influences of different factors, including whether the transverse frames are actually built, longitudinal and transverse welding residual stresses, and unloaded edge boundaries, on the ultimate strength and failure mode of a real hull bottom full-scale stiffened plate under axial compression and lateral pressure are investigated via numerical analysis. Result shows that the failure mode of the stiffened plate under axial compression is the tripping of the stiffeners. Whether transverse frames are built has little effect on the ultimate strength of the stiffened plate under axial compression, which can be replaced by the degree of freedom constraint. However, when lateral pressure is present, the transverse frame cannot be simply replaced by a free-degree constraint. The longitudinal residual stress has a greater effect on the ultimate strength, whereas the effect of the transverse residual stress is smaller. Stronger unloaded edge boundary conditions can slightly enhance the stiffness and ultimate strength of the stiffened plate. Under combined axial compression and lateral pressure, the failure mode of stiffened plates changes from the tripping of stiffeners to beam-column failure, as the lateral pressure increases. The ability of stiffened plates in which transverse frames are actually built out to resist beam-column shape deformation becomes weaker with lower ultimate strength. Stronger unloaded edge boundary conditions can improve the ability of stiffened plates to resist beam-column deformation and increase the ultimate strength.
2025, 39(1)
:13-26.
doi: 10.1007/s13344-025-0005-x
Abstract:
Jacket platforms constitute the foundational infrastructure of offshore oil and gas field exploitation. How to efficiently and accurately monitor the mechanical properties of jacket structures is one of the key problems to be solved to ensure the safe operation of the platform. To address the practical engineering problem that it is difficult to monitor the stress response of the tubular joints of jacket platforms online, a digital twin reduced-order method for real-time prediction of the stress response of tubular joints is proposed. In the offline construction phase, multi-scale modeling and multi-parameter experimental design methods are used to obtain the stress response data set of the jacket structure. Proper orthogonal decomposition is employed to extract the main feature information from the snapshot matrix, resulting in a reduced-order basis. The leave-one-out cross-validation method is used to select the optimal modal order for constructing the reduced-order model (ROM). In the online prediction phase, a digital twin model of the tubular joint is established, and the prediction performance of the ROM is analyzed and verified through using random environmental load and field environmental monitoring data. The results indicate that, compared with traditional numerical simulations of tubular joints, the ROM based on the proposed reduced-order method is more efficient in predicting the stress response of tubular joints while ensuring accuracy and robustness.
Jacket platforms constitute the foundational infrastructure of offshore oil and gas field exploitation. How to efficiently and accurately monitor the mechanical properties of jacket structures is one of the key problems to be solved to ensure the safe operation of the platform. To address the practical engineering problem that it is difficult to monitor the stress response of the tubular joints of jacket platforms online, a digital twin reduced-order method for real-time prediction of the stress response of tubular joints is proposed. In the offline construction phase, multi-scale modeling and multi-parameter experimental design methods are used to obtain the stress response data set of the jacket structure. Proper orthogonal decomposition is employed to extract the main feature information from the snapshot matrix, resulting in a reduced-order basis. The leave-one-out cross-validation method is used to select the optimal modal order for constructing the reduced-order model (ROM). In the online prediction phase, a digital twin model of the tubular joint is established, and the prediction performance of the ROM is analyzed and verified through using random environmental load and field environmental monitoring data. The results indicate that, compared with traditional numerical simulations of tubular joints, the ROM based on the proposed reduced-order method is more efficient in predicting the stress response of tubular joints while ensuring accuracy and robustness.
2025, 39(1)
:27-42.
doi: 10.1007/s13344-025-0002-0
Abstract:
Experimental studies were conducted on two high-strength steel plate-frame structures with different truss spacings under various impact velocities to investigate the dynamic mechanical properties of hull plate-frame structures under drop weight impact. The results showed that decreasing the main beam spacing can effectively increase the structural stiffness, reduce the maximum deformation, and increase the damage range. Furthermore, to simulate the impact tests accurately, static and dynamic tensile tests at different strain rates were carried out, and the Cowper-Symonds model parameters were fitted via experimental data. The material properties obtained from the tensile tests were used as inputs for numerical simulations with the numerical results coincide with the experimental results. A systematic analysis and discussion were conducted on the effects of truss spacing and truss width on the dynamic response of the reinforced plates, and an optimal range for the ratio of truss spacing to truss width was proposed. In addition, a mesh size sensitivity analysis for ship hull plate frame collision simulations was performed. The applicability of the EPS, MMC, and RTCL failure criteria in the simulation of plate-frame structures was investigated via finite element simulations of falling weight impact tests. The research findings provide a reference for ship hull structure design and resilience assessment.
Experimental studies were conducted on two high-strength steel plate-frame structures with different truss spacings under various impact velocities to investigate the dynamic mechanical properties of hull plate-frame structures under drop weight impact. The results showed that decreasing the main beam spacing can effectively increase the structural stiffness, reduce the maximum deformation, and increase the damage range. Furthermore, to simulate the impact tests accurately, static and dynamic tensile tests at different strain rates were carried out, and the Cowper-Symonds model parameters were fitted via experimental data. The material properties obtained from the tensile tests were used as inputs for numerical simulations with the numerical results coincide with the experimental results. A systematic analysis and discussion were conducted on the effects of truss spacing and truss width on the dynamic response of the reinforced plates, and an optimal range for the ratio of truss spacing to truss width was proposed. In addition, a mesh size sensitivity analysis for ship hull plate frame collision simulations was performed. The applicability of the EPS, MMC, and RTCL failure criteria in the simulation of plate-frame structures was investigated via finite element simulations of falling weight impact tests. The research findings provide a reference for ship hull structure design and resilience assessment.
2025, 39(1)
:43-57.
doi: 10.1007/s13344-025-0003-z
Abstract:
In the process of developing oil and gas resources in the Arctic, the impact of icebergs can pose a considerable threat to the structural safety of semi-submersible mooring platforms in ice regions. On the basis of the arbitrary Lagrangian Eulerian (ALE) algorithm, a numerical model for the interaction between an iceberg and a semi-submersible mooring platform is built in this work. First, a mooring system with a link element is designed and validated. An ice material model for the target iceberg is built and validated. A numerical model for the interaction between an iceberg and a semi-submersible mooring platform is then built. A parametric study (cable angle, tension angle and number of cables) is carried out to study the performance of the mooring system. The collision process between the semi-submersible mooring platform and the iceberg in the polar marine environment can be predicted by the present numerical model, and then the optimal mooring arrangement scheme can be obtained. The research results in this work can provide a reference for the design of mooring systems.
In the process of developing oil and gas resources in the Arctic, the impact of icebergs can pose a considerable threat to the structural safety of semi-submersible mooring platforms in ice regions. On the basis of the arbitrary Lagrangian Eulerian (ALE) algorithm, a numerical model for the interaction between an iceberg and a semi-submersible mooring platform is built in this work. First, a mooring system with a link element is designed and validated. An ice material model for the target iceberg is built and validated. A numerical model for the interaction between an iceberg and a semi-submersible mooring platform is then built. A parametric study (cable angle, tension angle and number of cables) is carried out to study the performance of the mooring system. The collision process between the semi-submersible mooring platform and the iceberg in the polar marine environment can be predicted by the present numerical model, and then the optimal mooring arrangement scheme can be obtained. The research results in this work can provide a reference for the design of mooring systems.
2025, 39(1)
:58-72.
doi: 10.1007/s13344-025-0004-y
Abstract:
In this work, the selected icebreaker model experiment is performed in a towing tank. We focus on the influence of seawater salinity on ship ice resistance in the ice floe field and the innovative ice model and ship model test technology, including the similitude rule of ship model tests, test principles, and validation with full-scale ship data. A formula for calculating the relationship between the temperature and salinity of the water is constructed, which can be used to simulate the role of seawater in freshwater ice pools. On this basis, the effect of salinity on the resistance of ships sailing in broken ice fields is studied. A technique in which artificial ice made of polyethylene spheres is used to simulate ice resistance is proposed. With a series of ship model experiments in spherical and triangular ice fields, the effects of salinity and velocity on the ice resistance test of the ship model are analyzed. A relationship of the ice resistance of the ship model to the spherical ice field and the triangular ice field is proposed. The conversion results are consistent with onsite data of the full-size ship, which verifies the method of converting the test results of the ship model to the prototype.
In this work, the selected icebreaker model experiment is performed in a towing tank. We focus on the influence of seawater salinity on ship ice resistance in the ice floe field and the innovative ice model and ship model test technology, including the similitude rule of ship model tests, test principles, and validation with full-scale ship data. A formula for calculating the relationship between the temperature and salinity of the water is constructed, which can be used to simulate the role of seawater in freshwater ice pools. On this basis, the effect of salinity on the resistance of ships sailing in broken ice fields is studied. A technique in which artificial ice made of polyethylene spheres is used to simulate ice resistance is proposed. With a series of ship model experiments in spherical and triangular ice fields, the effects of salinity and velocity on the ice resistance test of the ship model are analyzed. A relationship of the ice resistance of the ship model to the spherical ice field and the triangular ice field is proposed. The conversion results are consistent with onsite data of the full-size ship, which verifies the method of converting the test results of the ship model to the prototype.
2025, 39(1)
:73-85.
doi: 10.1007/s13344-024-0086-y
Abstract:
This study proposed a novel experimental platform to conduct dynamic loading tests of a truncated model steel catenary riser (SCR) within the touchdown zone (TDZ). The facilities of the platform, including a soil tank, a loading system, and a soil stirring system, are introduced in detail. A steel pipe with the same diameter as the in situ SCR has been used in the laboratory tests to investigate the vertical motion of the pipe and the effect of the trench on the lateral motion. As the amplitude of the vertical motion increases, the depth of the trench deepens, the bending moment range increases, and the excess pore water pressure at the bottom of the pipeline first accumulates and then dissipates during loading. The development trend of the trench depth and the influence of the soil strength on the SCR bending moment are also studied. During the test, a seabed trench develops, and its shape is similar to that of the in situ trench.
This study proposed a novel experimental platform to conduct dynamic loading tests of a truncated model steel catenary riser (SCR) within the touchdown zone (TDZ). The facilities of the platform, including a soil tank, a loading system, and a soil stirring system, are introduced in detail. A steel pipe with the same diameter as the in situ SCR has been used in the laboratory tests to investigate the vertical motion of the pipe and the effect of the trench on the lateral motion. As the amplitude of the vertical motion increases, the depth of the trench deepens, the bending moment range increases, and the excess pore water pressure at the bottom of the pipeline first accumulates and then dissipates during loading. The development trend of the trench depth and the influence of the soil strength on the SCR bending moment are also studied. During the test, a seabed trench develops, and its shape is similar to that of the in situ trench.
2025, 39(1)
:86-99.
doi: 10.1007/s13344-025-0006-9
Abstract:
Buckling failure in submarine cables presents a prevalent challenge in ocean engineering. This work aims to explore the buckling behavior of umbilical cables with damaged sheaths subjected to compression and bending cyclic loads. A finite element model is devised, incorporating a singular armor wire, a rigid core, and a damaged sheath. To scrutinize the buckling progression and corresponding deformation, axial compression and bending cyclic loads are introduced. The observations reveal that a reduction in axial compression results in a larger number of cycles before buckling ensues and progressively shifts the buckling position toward the extrados and fixed end. Decreasing the bending radius precipitates a reduction in the buckling cycle number and minimizes the deformation in the armor wire. Furthermore, an empirical model is presented to predict the occurrence of birdcage buckling, providing a means to anticipate buckling events and to estimate the requisite number of cycles leading to buckling.
Buckling failure in submarine cables presents a prevalent challenge in ocean engineering. This work aims to explore the buckling behavior of umbilical cables with damaged sheaths subjected to compression and bending cyclic loads. A finite element model is devised, incorporating a singular armor wire, a rigid core, and a damaged sheath. To scrutinize the buckling progression and corresponding deformation, axial compression and bending cyclic loads are introduced. The observations reveal that a reduction in axial compression results in a larger number of cycles before buckling ensues and progressively shifts the buckling position toward the extrados and fixed end. Decreasing the bending radius precipitates a reduction in the buckling cycle number and minimizes the deformation in the armor wire. Furthermore, an empirical model is presented to predict the occurrence of birdcage buckling, providing a means to anticipate buckling events and to estimate the requisite number of cycles leading to buckling.
2025, 39(1)
:100-110.
doi: 10.1007/s13344-025-0007-8
Abstract:
The deepwater subsea wellhead (SW) system is the foundation for the construction of oil and gas wells and the crucial channel for operation. During riser connection operation, the SW system is subjected to cyclic dynamic loads which cause fatigue damage to the SW system, and continuously accumulated fatigue damage leads to fatigue failure of the SW system, rupture, and even blowout accidents. This paper proposes a hybrid Bayesian network (HBN)-based dynamic reliability assessment approach for deepwater SW systems during their service life. In the proposed approach, the relationship between the accumulation of fatigue damage and the fatigue failure probability of the SW system is predicted, only considering normal conditions. The HBN model, which includes the accumulation of fatigue damage under normal conditions and the other factors affecting the fatigue of the SW system, is subsequently developed. When predictive and diagnostic analysis techniques are adopted, the dynamic reliability of the SW system is achieved, and the most influential factors are determined. Finally, corresponding safety control measures are proposed to improve the reliability of the SW system effectively. The results illustrate that the fatigue failure speed increases rapidly when the accumulation fatigue damage is larger than 0.45 under normal conditions and that the reliability of the SW system is larger than 94% within the design life.
The deepwater subsea wellhead (SW) system is the foundation for the construction of oil and gas wells and the crucial channel for operation. During riser connection operation, the SW system is subjected to cyclic dynamic loads which cause fatigue damage to the SW system, and continuously accumulated fatigue damage leads to fatigue failure of the SW system, rupture, and even blowout accidents. This paper proposes a hybrid Bayesian network (HBN)-based dynamic reliability assessment approach for deepwater SW systems during their service life. In the proposed approach, the relationship between the accumulation of fatigue damage and the fatigue failure probability of the SW system is predicted, only considering normal conditions. The HBN model, which includes the accumulation of fatigue damage under normal conditions and the other factors affecting the fatigue of the SW system, is subsequently developed. When predictive and diagnostic analysis techniques are adopted, the dynamic reliability of the SW system is achieved, and the most influential factors are determined. Finally, corresponding safety control measures are proposed to improve the reliability of the SW system effectively. The results illustrate that the fatigue failure speed increases rapidly when the accumulation fatigue damage is larger than 0.45 under normal conditions and that the reliability of the SW system is larger than 94% within the design life.
2025, 39(1)
:111-124.
doi: 10.1007/s13344-025-0008-7
Abstract:
This paper presents a new type of steel pipe pile wharf connection node. The steel pipe and concrete are connected by ultra-high performance concrete (UHPC) grouting to improve the bonding performance between the concrete and steel pipe and enhance the mechanical performance of the specimen under earthquake action. A bond test between the steel tube and the concrete was carried out. Considering the interaction between materials, the proposed concrete constitutive model was proposed. The finite element analysis method was used to simulate the structural response of the UHPC grouting connection concrete-filled steel tube (UCFST) beam-pile joint and the normal strength concrete-filled steel tube (NCFST) beam-pile joint under earthquake action. The results indicate that the bond performance between the UHPC and the steel tube is stronger. The UCFST specimen has a relatively high bearing capacity and stiffness. When the ratio of the UHPC grouting layer to the component diameter is 0.5, the bearing capacity is the highest. When the ratio is 0.37, the ductility is the highest. When the ratio is 0.25, it combines the advantages of the two situations mentioned above. UCFST specimens have better energy dissipation capacity and damage, which can effectively improve the seismic performance of components.
This paper presents a new type of steel pipe pile wharf connection node. The steel pipe and concrete are connected by ultra-high performance concrete (UHPC) grouting to improve the bonding performance between the concrete and steel pipe and enhance the mechanical performance of the specimen under earthquake action. A bond test between the steel tube and the concrete was carried out. Considering the interaction between materials, the proposed concrete constitutive model was proposed. The finite element analysis method was used to simulate the structural response of the UHPC grouting connection concrete-filled steel tube (UCFST) beam-pile joint and the normal strength concrete-filled steel tube (NCFST) beam-pile joint under earthquake action. The results indicate that the bond performance between the UHPC and the steel tube is stronger. The UCFST specimen has a relatively high bearing capacity and stiffness. When the ratio of the UHPC grouting layer to the component diameter is 0.5, the bearing capacity is the highest. When the ratio is 0.37, the ductility is the highest. When the ratio is 0.25, it combines the advantages of the two situations mentioned above. UCFST specimens have better energy dissipation capacity and damage, which can effectively improve the seismic performance of components.
2025, 39(1)
:125-134.
doi: 10.1007/s13344-025-0009-6
Abstract:
In channel reservoirs, a quantitative characterization of landslide-generated impulse wave-structure interactions is essential for evaluating potential damage to infrastructure and dams. In this study, the problem of landslide-generated impulse waves that attack a vertical wall was investigated in a wave channel via a smooth particle hydrodynamics (SPH) method coupled with a Chrono model. The results indicated that the longitudinal velocity beneath the leading wave crest of an incident impulse wave deviated significantly from solitary wave theory. Moreover, the variation rate in the vertical velocity along the water column coincided with the theoretical prediction only for small wave amplitudes. Nevertheless, the maximum run-up height of an impulse wave can be accurately predicted via the solitary wave theory. Moreover, the maximum wall force during impulse wave-wall interaction was significantly larger than that during solitary wave reflection, particularly for high incident wave amplitudes. Overall, the present study demonstrated some striking differences in the interactions of landslide-generated impulse waves and solitary waves with a vertical wall.
In channel reservoirs, a quantitative characterization of landslide-generated impulse wave-structure interactions is essential for evaluating potential damage to infrastructure and dams. In this study, the problem of landslide-generated impulse waves that attack a vertical wall was investigated in a wave channel via a smooth particle hydrodynamics (SPH) method coupled with a Chrono model. The results indicated that the longitudinal velocity beneath the leading wave crest of an incident impulse wave deviated significantly from solitary wave theory. Moreover, the variation rate in the vertical velocity along the water column coincided with the theoretical prediction only for small wave amplitudes. Nevertheless, the maximum run-up height of an impulse wave can be accurately predicted via the solitary wave theory. Moreover, the maximum wall force during impulse wave-wall interaction was significantly larger than that during solitary wave reflection, particularly for high incident wave amplitudes. Overall, the present study demonstrated some striking differences in the interactions of landslide-generated impulse waves and solitary waves with a vertical wall.
2025, 39(1)
:135-148.
doi: 10.1007/s13344-025-0010-0
Abstract:
Floating breakwaters (FBs) are commonly employed for the protection of coastal installations. In this work, a convex-type floating breakwater (FB) is proposed, and its hydrodynamic characteristics are studied through systematic laboratory experiments. Two different deck widths and two different mooring systems are set in the experiment. The transmission coefficients, reflection coefficients, motion responses and mooring forces of convex-type FBs are obtained in experiments. The influences of the deck width and mooring system on the hydrodynamic characteristics of the proposed FB are analyzed and compared. The experimental results show that the reflection coefficient and mooring force of the convex-type FB with a cross-mooring system are significantly larger than those of the convex-type FB with a parallel-mooring system. A convex-type FB with a larger deck width has a higher reflection coefficient. The convex-type FBs with cross- and parallel- mooring systems have similar surge and heave motions, but the cross-mooring results in small roll motion. In addition, reliable prediction formulas for the transmission coefficient of convex-type FBs with different mooring systems have been developed, which are important for engineering design.
Floating breakwaters (FBs) are commonly employed for the protection of coastal installations. In this work, a convex-type floating breakwater (FB) is proposed, and its hydrodynamic characteristics are studied through systematic laboratory experiments. Two different deck widths and two different mooring systems are set in the experiment. The transmission coefficients, reflection coefficients, motion responses and mooring forces of convex-type FBs are obtained in experiments. The influences of the deck width and mooring system on the hydrodynamic characteristics of the proposed FB are analyzed and compared. The experimental results show that the reflection coefficient and mooring force of the convex-type FB with a cross-mooring system are significantly larger than those of the convex-type FB with a parallel-mooring system. A convex-type FB with a larger deck width has a higher reflection coefficient. The convex-type FBs with cross- and parallel- mooring systems have similar surge and heave motions, but the cross-mooring results in small roll motion. In addition, reliable prediction formulas for the transmission coefficient of convex-type FBs with different mooring systems have been developed, which are important for engineering design.
Jin-bo LIN,
Li-li HU,
Hui YANG,
Yan-li HE,
Hong-fei MAO,
Dong-bin HE,
Jian ZHENG,
Lei LI,
Guang-lin WU
2025, 39(1)
:149-159.
doi: 10.1007/s13344-025-0011-z
Abstract:
The interaction between extreme waves and structures is a crucial study area in marine science, as it significantly influences safety and disaster prevention strategies for marine and coastal engineering. To investigate the flow field of a semi-submersible against extreme waves, a model simulating solitary wave interactions with the semi-submersible system was developed via the meshless smoothed particle hydrodynamics (SPH) method and Rayleigh’s theory. Notably, the wave surface and wave load results obtained from the SPH model, compared with those of OpenFOAM, result in an interaction test case between solitary waves and partially submerged rectangular obstacles and show good agreement, with a maximum relative error of 3.4%. An analysis of the calculated results of the semi-submersible facing solitary waves revealed several key findings: overtopping, which decreases with increasing water depth, occurs on the structure when the non-submerged ratio is 0.33 and the wave height surpasses 0.2 m. The transmission coefficient decreases with increasing wave height but increases as the water depth increases. Furthermore, the reflection coefficient peaks at a wave height H0 = 0.2 m. The dissipation coefficient displays a valley trend with a small water depth, whereas it increases monotonically with increasing water depth. The dissipation coefficient decreases with increasing water depth.
The interaction between extreme waves and structures is a crucial study area in marine science, as it significantly influences safety and disaster prevention strategies for marine and coastal engineering. To investigate the flow field of a semi-submersible against extreme waves, a model simulating solitary wave interactions with the semi-submersible system was developed via the meshless smoothed particle hydrodynamics (SPH) method and Rayleigh’s theory. Notably, the wave surface and wave load results obtained from the SPH model, compared with those of OpenFOAM, result in an interaction test case between solitary waves and partially submerged rectangular obstacles and show good agreement, with a maximum relative error of 3.4%. An analysis of the calculated results of the semi-submersible facing solitary waves revealed several key findings: overtopping, which decreases with increasing water depth, occurs on the structure when the non-submerged ratio is 0.33 and the wave height surpasses 0.2 m. The transmission coefficient decreases with increasing wave height but increases as the water depth increases. Furthermore, the reflection coefficient peaks at a wave height H0 = 0.2 m. The dissipation coefficient displays a valley trend with a small water depth, whereas it increases monotonically with increasing water depth. The dissipation coefficient decreases with increasing water depth.
2025, 39(1)
:160-165.
doi: 10.1007/s13344-025-0012-y
Abstract:
With respect to oceanic ?uid dynamics, certain models have appeared, e.g., an extended time-dependent (3+1)-dimensional shallow water wave equation in an ocean or a river, which we investigate in this paper. Using symbolic computation, we ?nd out, on one hand, a set of bilinear auto-B?cklund transformations, which could connect certain solutions of that equation with other solutions of that equation itself, and on the other hand, a set of similarity reductions, which could go from that equation to a known ordinary differential equation. The results in this paper depend on all the oceanic variable coefficients in that equation.
With respect to oceanic ?uid dynamics, certain models have appeared, e.g., an extended time-dependent (3+1)-dimensional shallow water wave equation in an ocean or a river, which we investigate in this paper. Using symbolic computation, we ?nd out, on one hand, a set of bilinear auto-B?cklund transformations, which could connect certain solutions of that equation with other solutions of that equation itself, and on the other hand, a set of similarity reductions, which could go from that equation to a known ordinary differential equation. The results in this paper depend on all the oceanic variable coefficients in that equation.
2025, 39(1)
:166-178.
doi: 10.1007/s13344-025-0013-x
Abstract:
In this work, an oscillating-body wave energy converter (OBWEC) with a hydraulic power take-off (PTO) system named “Dolphin 1” is designed, in which the hydraulic PTO system is equivalent to a transfer station and plays a crucial role in ensuring the stability of the electrical energy output and the efficiency of the overall system. A corresponding mathematical model for the hydraulic PTO system has been established, the factors that influence its performance have been studied, and an algorithm for solving the optimal working pressure has been derived in this paper. Moreover, a PID control method to enable the hydraulic PTO system to automatically achieve optimal performance under different wave conditions has been designed. The results indicate that, compared with single-chamber hydraulic cylinders, double-chamber hydraulic cylinders have a wider application range and greater performance; the accumulator can stabilize the output power of the hydraulic PTO system and slightly increase it; excessively large or small hydraulic motor displacement hinders system performance; and each wave condition corresponds to a unique optimal working pressure for the hydraulic PTO system. In addition, the relationship between the optimal working pressure\begin{document}$ {P}_{\mathrm{m}} $\end{document} \begin{document}$ {P}_{\mathrm{h}} $\end{document} \begin{document}$ {P}_{\mathrm{m}}^{2}={{\displaystyle\int }_{{t}_{1}}^{{t}_{2}}{P}_{\mathrm{h}}^{2}\mathrmqmqou0myt}\bigg/({{t}_{2}-{t}_{1}}) $\end{document}
In this work, an oscillating-body wave energy converter (OBWEC) with a hydraulic power take-off (PTO) system named “Dolphin 1” is designed, in which the hydraulic PTO system is equivalent to a transfer station and plays a crucial role in ensuring the stability of the electrical energy output and the efficiency of the overall system. A corresponding mathematical model for the hydraulic PTO system has been established, the factors that influence its performance have been studied, and an algorithm for solving the optimal working pressure has been derived in this paper. Moreover, a PID control method to enable the hydraulic PTO system to automatically achieve optimal performance under different wave conditions has been designed. The results indicate that, compared with single-chamber hydraulic cylinders, double-chamber hydraulic cylinders have a wider application range and greater performance; the accumulator can stabilize the output power of the hydraulic PTO system and slightly increase it; excessively large or small hydraulic motor displacement hinders system performance; and each wave condition corresponds to a unique optimal working pressure for the hydraulic PTO system. In addition, the relationship between the optimal working pressure
Mursid Ocid,
Malau Karno,
Yudo Hartono,
Tuswan,
Luqman Hakim Muhammad,
Firdhaus Ahmad,
Trimulyono Andi,
Iqbal Muhammad
2025, 39(1)
:179-189.
doi: 10.1007/s13344-025-0014-9
Abstract:
Shallow water infrastructure needs to support increased activity on the shores of Semarang. This study chooses several pontoons because of their good stability, rolling motion, and more expansive space. A coupled simulation method consisting of hydrodynamic and structural calculations has been used to evaluate a catamaran pontoon’s motion and structural integrity. Four different space sizes are set for the pontoon system: 5 m, 5.5 m, 6 m, and 6.5 m. The frequency domain shows that the pontoon space affects the RAO in wave periods ranging from 3 s to 5 s. At wave periods of 3 s, 4 s, and 5 s, the pontoon space significantly affects the maximum motion and chain tension parameter values, which are evaluated via time domain simulation. The critical stress of the pontoon is shown at a wave period of 5 s for 5 m and 5.5 m of pontoon space, which shows that the stress can reach 248 MPa.
Shallow water infrastructure needs to support increased activity on the shores of Semarang. This study chooses several pontoons because of their good stability, rolling motion, and more expansive space. A coupled simulation method consisting of hydrodynamic and structural calculations has been used to evaluate a catamaran pontoon’s motion and structural integrity. Four different space sizes are set for the pontoon system: 5 m, 5.5 m, 6 m, and 6.5 m. The frequency domain shows that the pontoon space affects the RAO in wave periods ranging from 3 s to 5 s. At wave periods of 3 s, 4 s, and 5 s, the pontoon space significantly affects the maximum motion and chain tension parameter values, which are evaluated via time domain simulation. The critical stress of the pontoon is shown at a wave period of 5 s for 5 m and 5.5 m of pontoon space, which shows that the stress can reach 248 MPa.
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