Applied Ocean Research最新文献

英文中文

Optimizing time-delay estimation for underwater acoustic positioning in tank inspection robots to mitigate reflection interference

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-01-01 DOI: 10.1016/j.apor.2025.104427

Zhenyu Xu, Zhangwei Chen

Robot inspection of large storage tanks has become the primary method for addressing hidden risks in the petrochemical industry. Accurate positioning of Tank Inspection Robots (TIR) is crucial in this process. However, the unique characteristics of the liquid medium and tank walls introduce challenges such as noise, reverberations, and multipath effects, which frequently complicate the acoustic positioning of robots. These issues are further complicated by numerous interface reflections. To address the problems caused by reflections, this paper focuses on time-delay estimation for underwater acoustic positioning. It analyzes the impact of reflections on various acoustic positioning methods and simplifies the time-delay estimation process within the Time Difference of Arrival (TDOA) localization algorithm in reverberant environments. To this end, the paper introduces the AMCOCEP algorithm, which integrates Generalized Cross-Correlation, the cepstrum, and the Average Magnitude Difference Function (AMDF). The effectiveness of the proposed positioning model and method is validated by positioning a robot within a storage tank and comparing positioning accuracy before and after algorithm optimization. According to the experimental results, the AMCOCEP algorithm reduces the average error by 1.07 cm and improves the average accuracy by 30.7 %.

{"title":"Optimizing time-delay estimation for underwater acoustic positioning in tank inspection robots to mitigate reflection interference","authors":"Zhenyu Xu, Zhangwei Chen","doi":"10.1016/j.apor.2025.104427","DOIUrl":"10.1016/j.apor.2025.104427","url":null,"abstract":"<div><div>Robot inspection of large storage tanks has become the primary method for addressing hidden risks in the petrochemical industry. Accurate positioning of Tank Inspection Robots (TIR) is crucial in this process. However, the unique characteristics of the liquid medium and tank walls introduce challenges such as noise, reverberations, and multipath effects, which frequently complicate the acoustic positioning of robots. These issues are further complicated by numerous interface reflections. To address the problems caused by reflections, this paper focuses on time-delay estimation for underwater acoustic positioning. It analyzes the impact of reflections on various acoustic positioning methods and simplifies the time-delay estimation process within the Time Difference of Arrival (TDOA) localization algorithm in reverberant environments. To this end, the paper introduces the AMCOCEP algorithm, which integrates Generalized Cross-Correlation, the cepstrum, and the Average Magnitude Difference Function (AMDF). The effectiveness of the proposed positioning model and method is validated by positioning a robot within a storage tank and comparing positioning accuracy before and after algorithm optimization. According to the experimental results, the AMCOCEP algorithm reduces the average error by 1.07 cm and improves the average accuracy by 30.7 %.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"154 ","pages":"Article 104427"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Nonlinear thermo-mechanical bending analysis of variable-thickness parallelogram plates in curved hull via a homotopy-based wavelet method

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-01-01 DOI: 10.1016/j.apor.2024.104334

Qiang Yu , Junfeng Xiao , Hang Xu , Zixin Wu

Due to the variable-thickness parallelogram plates in ocean structure are characterized by the presence of strong moment singularity at supported obtuse corners, the wide application has turned the nonlinear mechanical analysis into one of the most important engineering concerns. In the paper, a refined geometrically nonlinear bending model of variable-thickness orthotropic parallelogram plates in curved hull under thermo-mechanical loads is proposed, while influences of linearly or quadratically thickened thickness in symmetrical or unsymmetrical profile on mechanical properties are thoroughly investigated. Three kinds of spatially thermal field in parallelogram domain are formulated on account of the coupled interaction of effects between in-plane distribution and thickness variation corresponding to the Dirichlet, Neumann and Robin thermal boundaries. A novel thickness-dependent Airy stress function is introduced overcoming the failure of traditional Airy stress function in equilibrium of in-plane forces, while the highly coupled and variable-coefficient nonlinear governing partial differential equations are firstly derived. The homotopy-based wavelet method is adopted to investigate the nonlinear thermo-elastic bending behaviors, while convergent process is verified and precision of obtained series solutions has been validated in excellent agreement with published results. The significant conclusion can be made that large-deflection nonlinear bending of such plates can be simplified with little discrepancy by omitting terms involving the derivatives of thickness variation in compatibility equation of deformation, which is generalized to the thermo-mechanical bending and greatly simplifies the analyzing procedures.

{"title":"Nonlinear thermo-mechanical bending analysis of variable-thickness parallelogram plates in curved hull via a homotopy-based wavelet method","authors":"Qiang Yu , Junfeng Xiao , Hang Xu , Zixin Wu","doi":"10.1016/j.apor.2024.104334","DOIUrl":"10.1016/j.apor.2024.104334","url":null,"abstract":"<div><div>Due to the variable-thickness parallelogram plates in ocean structure are characterized by the presence of strong moment singularity at supported obtuse corners, the wide application has turned the nonlinear mechanical analysis into one of the most important engineering concerns. In the paper, a refined geometrically nonlinear bending model of variable-thickness orthotropic parallelogram plates in curved hull under thermo-mechanical loads is proposed, while influences of linearly or quadratically thickened thickness in symmetrical or unsymmetrical profile on mechanical properties are thoroughly investigated. Three kinds of spatially thermal field in parallelogram domain are formulated on account of the coupled interaction of effects between in-plane distribution and thickness variation corresponding to the Dirichlet, Neumann and Robin thermal boundaries. A novel thickness-dependent Airy stress function is introduced overcoming the failure of traditional Airy stress function in equilibrium of in-plane forces, while the highly coupled and variable-coefficient nonlinear governing partial differential equations are firstly derived. The homotopy-based wavelet method is adopted to investigate the nonlinear thermo-elastic bending behaviors, while convergent process is verified and precision of obtained series solutions has been validated in excellent agreement with published results. The significant conclusion can be made that large-deflection nonlinear bending of such plates can be simplified with little discrepancy by omitting terms involving the derivatives of thickness variation in compatibility equation of deformation, which is generalized to the thermo-mechanical bending and greatly simplifies the analyzing procedures.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"154 ","pages":"Article 104334"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Hydrodynamic investigation of a new type of floating breakwaters integrated with porous baffles

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-01-01 DOI: 10.1016/j.apor.2024.104380

Kang-Zhuo Hu, Tiao-Jian Xu, Sen Wang

Due to their easy installation and low maintenance costs, floating breakwaters have attracted extensive attention from scholars, resulting in a series of new configurations. A novel floating breakwater integrated with porous baffles (PFB) was introduced in this research. Numerical simulations were applied to explore the interactions between the PFB and regular waves, and corresponding experiments were also completed to ensure the accuracy of the numerical results. Then, the impacts of the height, position, and porosity on the hydrodynamic performance of the PFB were analyzed through a series of numerical simulations. A comparison with conventional box-type floating breakwaters was also conducted. The results indicated that the porous baffles effectively improved the wave attenuation phenomenon and reduced the motion amplitude by weakening the wave particle velocity and concentrating the vortices near the porous baffles. Additionally, the performance of the PFB could be further increased by adjusting the baffle porosity and mounting position. The study provides valuable suggestions for the further improvement of floating breakwaters.

{"title":"Hydrodynamic investigation of a new type of floating breakwaters integrated with porous baffles","authors":"Kang-Zhuo Hu, Tiao-Jian Xu, Sen Wang","doi":"10.1016/j.apor.2024.104380","DOIUrl":"10.1016/j.apor.2024.104380","url":null,"abstract":"<div><div>Due to their easy installation and low maintenance costs, floating breakwaters have attracted extensive attention from scholars, resulting in a series of new configurations. A novel floating breakwater integrated with porous baffles (PFB) was introduced in this research. Numerical simulations were applied to explore the interactions between the PFB and regular waves, and corresponding experiments were also completed to ensure the accuracy of the numerical results. Then, the impacts of the height, position, and porosity on the hydrodynamic performance of the PFB were analyzed through a series of numerical simulations. A comparison with conventional box-type floating breakwaters was also conducted. The results indicated that the porous baffles effectively improved the wave attenuation phenomenon and reduced the motion amplitude by weakening the wave particle velocity and concentrating the vortices near the porous baffles. Additionally, the performance of the PFB could be further increased by adjusting the baffle porosity and mounting position. The study provides valuable suggestions for the further improvement of floating breakwaters.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"154 ","pages":"Article 104380"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimization of the mooring system of a floating wind turbine by developing a surrogate model-assisted evolutionary framework

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-01-01 DOI: 10.1016/j.apor.2024.104373

Ye An , Zhisheng Xia , Min Luo , Jian Zhang , Ronghua Zhu

In the design and optimization of Floating Wind Turbines (FWTs), there are challenges related to the large number of design parameters and the need for efficient and accurate calculation of turbine dynamic responses. To address these issues, this study proposes a surrogate model-assisted evolutionary framework for the mooring system optimization of shallow-water wind turbines. This distinct feature of the optimization framework lies in that it employs a sparse polynomial chaos expansion surrogate model to quickly predict the performance indicator values of FWTs with different mooring configurations and adopts the differential evolution algorithm to find the mooring parameter combination with the best performance, achieving efficient, accurate, and automated multi-parameter optimization. The framework is utilized to optimize the mooring system for a FWT at a relatively shallow water depth, through defining a mooring performance evaluation indicator as the objective function that comprehensively considers mooring line tensions, platform motions, anchor tensions, and the mooring line material cost. Based on the optimization application, the accuracy of the optimization framework is verified. The dynamic responses and safety assessments of the optimized FWT in the fatigue limit state (FLS) and ultimate limit state (ULS) are conducted. The results demonstrate the effectiveness of the proposed optimization framework in enhancing a FWT's performance according to flexibly defined objective functions.

{"title":"Optimization of the mooring system of a floating wind turbine by developing a surrogate model-assisted evolutionary framework","authors":"Ye An , Zhisheng Xia , Min Luo , Jian Zhang , Ronghua Zhu","doi":"10.1016/j.apor.2024.104373","DOIUrl":"10.1016/j.apor.2024.104373","url":null,"abstract":"<div><div>In the design and optimization of Floating Wind Turbines (FWTs), there are challenges related to the large number of design parameters and the need for efficient and accurate calculation of turbine dynamic responses. To address these issues, this study proposes a surrogate model-assisted evolutionary framework for the mooring system optimization of shallow-water wind turbines. This distinct feature of the optimization framework lies in that it employs a sparse polynomial chaos expansion surrogate model to quickly predict the performance indicator values of FWTs with different mooring configurations and adopts the differential evolution algorithm to find the mooring parameter combination with the best performance, achieving efficient, accurate, and automated multi-parameter optimization. The framework is utilized to optimize the mooring system for a FWT at a relatively shallow water depth, through defining a mooring performance evaluation indicator as the objective function that comprehensively considers mooring line tensions, platform motions, anchor tensions, and the mooring line material cost. Based on the optimization application, the accuracy of the optimization framework is verified. The dynamic responses and safety assessments of the optimized FWT in the fatigue limit state (FLS) and ultimate limit state (ULS) are conducted. The results demonstrate the effectiveness of the proposed optimization framework in enhancing a FWT's performance according to flexibly defined objective functions.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"154 ","pages":"Article 104373"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analyses on flow structures behind submersible with flexible appendage during floating based on continuous wavelet transform and dynamic mode decomposition

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-01-01 DOI: 10.1016/j.apor.2024.104397

Fei Yan , Weiyu Kong , Akira Rinoshika , Bo Song , Jian Zhang

This study propounded a new method of installing flexible appendage on the surface of a submersible to modify the wake structure of the submersible as it floats, and explored a method of drag reduction of floating submersible. A comparative analysis of the flow structure of submersibles with varying appendage lengths was done to understand the disturbance characteristics of the wake flow structure of submersible, and the high-speed particle image velocimetry (PIV) measurement experiment was conducted at a Reynolds number of 13448. The analysis of the time-averaged and transient flow fields revealed that flexible appendage was able to break up the large-scale vortices in the wake stream as the submersible floats, but this ability diminished as the length increasing of flexible appendage. Furthermore, in order to investigate the mechanism of this phenomenon, continuous wavelet transform (CWT) and dynamic mode decomposition (DMD) were performed. The results suggested that the flexible appendage inhibited large-scale flow, and the inhibition effect decreased with increasing of flexible appendage length based on CWT. It was demonstrated that the flexible appendage was capable of reducing the energy dominance of the large-scale vortex structure, thereby facilitating the transition from large-scale to small-scale vortices based on DMD. Concurrently, it was found that the intrusion of excessively lengthy appendage into the wake region resulted in the generation of additional disturbances and impeded the process of small-scale vortex shedding.

{"title":"Analyses on flow structures behind submersible with flexible appendage during floating based on continuous wavelet transform and dynamic mode decomposition","authors":"Fei Yan , Weiyu Kong , Akira Rinoshika , Bo Song , Jian Zhang","doi":"10.1016/j.apor.2024.104397","DOIUrl":"10.1016/j.apor.2024.104397","url":null,"abstract":"<div><div>This study propounded a new method of installing flexible appendage on the surface of a submersible to modify the wake structure of the submersible as it floats, and explored a method of drag reduction of floating submersible. A comparative analysis of the flow structure of submersibles with varying appendage lengths was done to understand the disturbance characteristics of the wake flow structure of submersible, and the high-speed particle image velocimetry (PIV) measurement experiment was conducted at a Reynolds number of 13448. The analysis of the time-averaged and transient flow fields revealed that flexible appendage was able to break up the large-scale vortices in the wake stream as the submersible floats, but this ability diminished as the length increasing of flexible appendage. Furthermore, in order to investigate the mechanism of this phenomenon, continuous wavelet transform (CWT) and dynamic mode decomposition (DMD) were performed. The results suggested that the flexible appendage inhibited large-scale flow, and the inhibition effect decreased with increasing of flexible appendage length based on CWT. It was demonstrated that the flexible appendage was capable of reducing the energy dominance of the large-scale vortex structure, thereby facilitating the transition from large-scale to small-scale vortices based on DMD. Concurrently, it was found that the intrusion of excessively lengthy appendage into the wake region resulted in the generation of additional disturbances and impeded the process of small-scale vortex shedding.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"154 ","pages":"Article 104397"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dynamic response analysis of a floating bridge with bottom damaged opening based on the Kane method

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-01-01 DOI: 10.1016/j.apor.2024.104365

Song Ji, Junyi Liu, Heng Huang, Guizhang Hu, Xujun Chen

To study the problem of the dynamic responses of the damaged floating bridge, this paper establishes the numerical model of a nonlinearly connected floating bridge based on the Kane method. The accuracy of the numerical model is verified by comparing the results from relevant literature and the model test conducted. Subsequently, considering the damaged opening at the bottom of the pontoon, the impact of different vehicle speeds, opening sizes, as well as connection gaps between pontoons on the dynamic responses of the damaged floating bridge is studied. Some conclusions are obtained: The flooding brought by the damaged opening causes the rise in vertical displacements of the damaged pontoon and the forces on the connectors. The opening and closing of the longitudinal gaps affect the sinking speed of the damaged pontoon, and the size of the gap influences both the maximum sinking displacement and the vibration period of the floating bridge. The maximum vertical displacements of the damaged pontoon and the flow rate variation at the opening location increase as the opening size expands. Reasonable selection of vehicle speeds and connection gaps between pontoons can prevent excessive dynamic responses of the damaged floating bridge.

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引用次数: 0

Electro-mechanical vibration control of functionally graded marine risers by a piezoelectric meta-structure design

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-01-01 DOI: 10.1016/j.apor.2024.104388

Feng Liang , Zhi-Qiang Chen

In this paper, a novel electro-mechanical meta-riser structure is designed aiming to suppress its vibration and wave propagation. The riser is made of porous functionally graded material (FGM), and is periodically attached with piezoelectric layers, each of which is connected with a multi-mode resonant shunt circuit to trigger multiple locally resonant (LR) band gaps (BGs). The periodically varying rigidity due to piezoelectric layers can also generate Bragg scattering (BS) BGs, resulting in a hybrid meta-structure. A point defect is introduced into the system by removing a certain piezoelectric layer. Theoretical analysis and finite element (FE) simulation both demonstrate the superior vibration control effect of the present meta-structure. Owing to the presence of defect, the riser presents a remarkable vibration response within the original BS BGs, reflecting the vibration energy localization and enabling energy harvesting by meta-structure designs. Different circuit designs and parameters can be used to regulate LR BGs, while the particular material composition of the riser will contribute to enhancing the BS BG performance. This study can provide a technical scheme for the vibration and elastic wave control of marine riser structures, and lay a theoretical foundation for the vibration energy harvesting by utilizing dynamical meta-structures.

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引用次数: 0

Numerical study of asymmetric pitching amplitude effects on energy extraction performance of a semi-activated hydrofoil in shear flows

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-01-01 DOI: 10.1016/j.apor.2024.104410

Hengliang Qu , Xueyan Li , Jinhai Zheng

As a representative tidal current energy device, the operational stability and energy extraction performance of hydrofoils are significantly influenced by shear flow. Inspired by natural models, including insects, birds, and fish, the amplitude asymmetric pitching has been proposed as a strategy to mitigate the adverse impacts of the shear flow. A 2-dimensional (2D) numerical model of a semi-activated hydrofoil was developed using ANSYS-Fluent computational fluid dynamics software to assess the feasibility of amplitude asymmetric pitching. Hydrofoils employing the asymmetric and symmetric pitching motions under uniform and shear flows were studied. The hydrodynamic response and energy extraction performance of the hydrofoil were compared at various shear rates, pitching amplitudes, and asymmetric ratios. The results indicate that amplitude asymmetric pitching enhances both the operational stability and energy extraction performance of the hydrofoil under shear flow conditions. The appropriate asymmetric ratio for stable operation and energy extraction varies depending on the pitching amplitude and shear rate. Appropriate asymmetric ratios were determined using the trial-and-error method. Additionally, flow field comparisons between the asymmetric and symmetric pitching motions elucidated the underlying mechanisms. The amplitude asymmetric pitching does not completely eliminate the adverse effects of shear flow on the hydrofoil's energy extraction performance. The power coefficient of the hydrofoil with an appropriate asymmetric ratio decreases with increasing shear rate.

{"title":"Numerical study of asymmetric pitching amplitude effects on energy extraction performance of a semi-activated hydrofoil in shear flows","authors":"Hengliang Qu , Xueyan Li , Jinhai Zheng","doi":"10.1016/j.apor.2024.104410","DOIUrl":"10.1016/j.apor.2024.104410","url":null,"abstract":"<div><div>As a representative tidal current energy device, the operational stability and energy extraction performance of hydrofoils are significantly influenced by shear flow. Inspired by natural models, including insects, birds, and fish, the amplitude asymmetric pitching has been proposed as a strategy to mitigate the adverse impacts of the shear flow. A 2-dimensional (2D) numerical model of a semi-activated hydrofoil was developed using ANSYS-Fluent computational fluid dynamics software to assess the feasibility of amplitude asymmetric pitching. Hydrofoils employing the asymmetric and symmetric pitching motions under uniform and shear flows were studied. The hydrodynamic response and energy extraction performance of the hydrofoil were compared at various shear rates, pitching amplitudes, and asymmetric ratios. The results indicate that amplitude asymmetric pitching enhances both the operational stability and energy extraction performance of the hydrofoil under shear flow conditions. The appropriate asymmetric ratio for stable operation and energy extraction varies depending on the pitching amplitude and shear rate. Appropriate asymmetric ratios were determined using the trial-and-error method. Additionally, flow field comparisons between the asymmetric and symmetric pitching motions elucidated the underlying mechanisms. The amplitude asymmetric pitching does not completely eliminate the adverse effects of shear flow on the hydrofoil's energy extraction performance. The power coefficient of the hydrofoil with an appropriate asymmetric ratio decreases with increasing shear rate.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"154 ","pages":"Article 104410"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental study on the effect of an underground structure on the seismic responses of saturated coral sand site

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-01-01 DOI: 10.1016/j.apor.2024.104392

Zhongxiang Zhang , Su Chen , Yongzhi Wang , Xiaojun Li

Understanding the effect of underground structures on the seismic responses of saturated coral sand sites is crucial for improving seismic design and preventing liquefaction disasters in island reef engineering. Despite advancements in this field, the specific effects of underground structures on the seismic behavior of coral sand sites remain underexplored. This study addresses this issue by conducting dynamic centrifuge shaking table tests on saturated coral sand sites, both with and without an underground structure. The seismic responses between the free field (FF) and structure field (SF) were compared in terms of pore pressure, acceleration, response spectra, and shear stress-strain behavior. Test results reveal that the presence of the underground structure led to a deeper liquefaction zone beneath it. The excess pore pressure in the soil layer above the structure dissipated rapidly after peaking and completely dissipated by the end of the seismic motions. Additionally, the soil near the bottom of the structure exhibited higher dilatancy. The structure amplified the acceleration of the soil above and near its bottom while reducing the acceleration of the soil adjacent to its sidewall. In the period range of 0.9–3.0 s, the presence of the structure weakened the attenuation of response spectra values for the soil adjacent to the sidewall and above the structure. Furthermore, the structure limited the deformation of the soil adjacent to its sidewall and increased the soil shear modulus.

{"title":"Experimental study on the effect of an underground structure on the seismic responses of saturated coral sand site","authors":"Zhongxiang Zhang , Su Chen , Yongzhi Wang , Xiaojun Li","doi":"10.1016/j.apor.2024.104392","DOIUrl":"10.1016/j.apor.2024.104392","url":null,"abstract":"<div><div>Understanding the effect of underground structures on the seismic responses of saturated coral sand sites is crucial for improving seismic design and preventing liquefaction disasters in island reef engineering. Despite advancements in this field, the specific effects of underground structures on the seismic behavior of coral sand sites remain underexplored. This study addresses this issue by conducting dynamic centrifuge shaking table tests on saturated coral sand sites, both with and without an underground structure. The seismic responses between the free field (FF) and structure field (SF) were compared in terms of pore pressure, acceleration, response spectra, and shear stress-strain behavior. Test results reveal that the presence of the underground structure led to a deeper liquefaction zone beneath it. The excess pore pressure in the soil layer above the structure dissipated rapidly after peaking and completely dissipated by the end of the seismic motions. Additionally, the soil near the bottom of the structure exhibited higher dilatancy. The structure amplified the acceleration of the soil above and near its bottom while reducing the acceleration of the soil adjacent to its sidewall. In the period range of 0.9–3.0 s, the presence of the structure weakened the attenuation of response spectra values for the soil adjacent to the sidewall and above the structure. Furthermore, the structure limited the deformation of the soil adjacent to its sidewall and increased the soil shear modulus.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"154 ","pages":"Article 104392"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Shoreline retreat and free overhang in overdeveloped tombolo behind detached breakwaters: Empirical, semi-analytical and numerical approach

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-01-01 DOI: 10.1016/j.apor.2024.104385

Changbin Lim , Jung L. Lee , John R.C. Hsu

Multiple detached breakwaters with narrow gaps have been constructed to dissipate wave energy to a beach and to promote salient or tombolo in the lee for shore protection since the 1960s. Although geometric parameters (breakwater length and distance offshore) are operative for the preliminary design of these structures, neither shoreline retreat from its initial position in the middle of each compartment was assessed, empirically or semi-analytically, nor was the tombolo's overhang length along the structure quantified, if it's overdeveloped. In this study, prototype data are collected to derive empirical relationship for a salient and tombolo geometry in static equilibrium. A semi-analytical approach is then used to derive algebraic equation for estimating shoreline retreat from an initial position, for three stages of shoreline planform, from a salient to initial tombolo and to an over-developed tombolo with free overhang. The results of this new approach are verified using empirical data and an approximate equation for shoreline retreat derived from the numerical results extended from the results of XBeach model. This also enables the backtracking to the existing shoreline, where extra hard protection is constructed in the middle of a compartment between consecutive DBWs, to its initial position. To mitigate the scenario of erosion, a preferred alternative combining nourishment with parabolic model is demonstrated to produce a stable beach with adequate beach buffer.

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