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Sparse Modal Decomposition Method Addressing Underdetermined Vortex-Induced Vibration Reconstruction Problem for Marine Risers

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China Ocean engineering 2024年第2期38卷 285-296页

作者： DU Zun-feng ZHU Hai-ming YU Jian-xing State Key laboratory of hydraulic engineering Intelligent construction and Operation School of Civil EngineeringTianjin UniversityTianjin 300350China

When investigating the vortex-induced vibration(VIV)of marine risers,extrapolating the dynamic response on the entire length based on limited sensor measurements is a crucial step in both laboratory experiments and fatigue monitoring of real *** problem is conventionally solved using the modal decomposition method,based on the principle that the response can be approximated by a weighted sum of limited vibration ***,the method is not valid when the problem is underdetermined,i.e.,the number of unknown mode weights is more than the number of known *** study proposed a sparse modal decomposition method based on the compressed sensing theory and the Compressive Sampling Matching Pursuit(Co Sa MP)algorithm,exploiting the sparsity of VIV in the modal *** the validation study based on high-order VIV experiment data,the proposed method successfully reconstructed the response using only seven acceleration measurements when the conventional methods failed.A primary advantage of the proposed method is that it offers a completely data-driven approach for the underdetermined VIV reconstruction problem,which is more favorable than existing model-dependent solutions for many practical applications such as riser structural health monitoring.

关键词： motion reconstruction vortex-induced vibration(VIV) marine riser modal decomposition method compressed sensing

Influence of Incomplete Soil Plugs on Bearing Capacities of Bucket Foundations in Clay

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China Ocean engineering 2024年第1期38卷 144-155页

作者： LI Hui-shan LIU Run YANG Xu LIAN Ji-jian State Key laboratory of hydraulic engineering Intelligent construction and Operation Tianjin UniversityTianjin 300072China School of Civil engineering Tianjin UniversityTianjin 300072China Institute of Marine Energy and Intelligent construction Tianjin University of TechnologyTianjin 300384China

Due to the uneven seabed and heaving of soil during pumping,incomplete soil plugs may occur during the installation of bucket foundations,and the impacts on the bearing capacities of bucket foundations need to be *** this paper,the contact ratio(the ratio of the top diameter of the soil plug to the diameter of the bucket)and the soil plug ratio(the ratio of the soil heave height to the skirt height)are defined to describe the shape and size of the incomplete soil ***,finite element models are established to investigate the bearing capacities of bucket foundations with incomplete soil plugs and the influences of the contact ratios,and the soil plug ratios on the bearing capacities are *** results show that the vertical bearing capacity of bucket foundations in homogeneous soil continuously improves with the increase of the contact ***,in normally consolidated soil,the vertical bearing capacity barely changes when the contact ratio is smaller than 0.75,while the bearing capacity suddenly increases when the contact ratio increases to 1 due to the change of failure *** contact ratio hardly affects the horizontal bearing capacity of bucket ***,the moment bearing capacity improves with the increase of the contact ratio for small aspect ratios,but hardly varies with increasing contact ratio for aspect ratios larger than ***,the reduction coefficient method is proposed based on this analysis to calculate the bearing capacities of bucket foundations considering the influence of incomplete soil *** comparison results show that the proposed reduction coefficient method can be used to evaluate the influences of incomplete soil plug on the bearing capacities of bucket foundations.

关键词： bucket foundation incomplete soil plug uniaxial bearing capacity contact ratio soil plug ratio

Impact pressure of waves generated by landslides on bank slopes

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Journal of Mountain Science 2024年第3期21卷 918-931页

作者： CAO Ting WANG Pingyi QIU Zhenfeng LIU Jie Key laboratory of hydraulic and Waterway engineering of Ministry of Education Chongqing Jiaotong UniversityChongqing 400074China engineering Research Center of Diagnosis technology and Instruments of Hydro-construction Chongqing Jiaotong UniversityChongqing 400074China

Impulse waves that are generated by landslides in narrow reservoir areas threaten the stability of buildings and bank *** discuss the action process and evolution law of the wave pressure on bank slopes,a three-dimensional physical model test that considers impulse waves generated by landslides was performed,and factors including landslide width,thickness,slope angles of the sliding surface,and bank slope angle were *** on wave forms on the bank slopes,wave pressure curve characteristics,and peak value,the action process of wave pressure could be divided into the following stages:maximum pulsating pressure stage,wave impact stage(when waves break),and stationary pulsation *** was found that wave breaking is dependent on the value of the surf similarity parameterξ.The distribution pattern of impact pressure decays linearly on both sides of the maximum impact pressure point,and the attenuation degree decreases when it attains 40%of the maximum ***,it is proposed that the prediction formula for the maximum effective impact pressure of the bank slope be related to the reciprocal of wave steepness,relative water depth,and slope *** prediction formula provides strong theoretical support for early safety warning and for predicting the bank slope under impulse waves generated by landslides.

关键词： Model test Impact pressure Action stage Breaking discrimination Distribution model

Properties and Characteristics of Regolith-Based Materials for Extraterrestrial construction

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engineering 2024年第6期37卷 159-181页

作者： Cheng Zhou Yuyue Gao Yan Zhou Wei She Yusheng Shi Lieyun Ding Changwen Miao national Center of technology Innovation for Digital construction Huazhong University of Science and TechnologyWuhan 430074China School of Civil and hydraulic engineering Huazhong University of Science and TechnologyWuhan 430074China School of Materials Science and engineering Southeast UniversityNanjing 214135China State Key laboratory of Materials Processing and Die&Mould technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The construction of extraterrestrial bases has become a new goal in the active exploration of deep *** the construction techniques,in situ resource-based construction is one of the most promising because of its good sustainability and acceptable economic cost,triggering the development of various types of extraterrestrial construction materials.A comprehensive survey and comparison of materials from the perspective of performance was conducted to provide suggestions for material selection and *** types of typical construction materials are discussed in terms of their reliability and applicability in extreme extraterrestrial ***,thermal and optical,and radiation-shielding properties are *** influencing factors and optimization methods for these properties are *** the perspective of material properties,the existing challenges lie in the comprehensive,long-term,and real characterization of regolith-based construction ***,the suggested future directions include the application of high-throughput characterization methods,accelerated durability tests,and conducting extraterrestrial experiments.

关键词： Extraterrestrial construction Characterization Mechanical property Thermal property Optical property Radiation-shielding

Comparison of microwave- and thermal-assisted rock fragmentation methods at different temperatures and loading rates

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International Journal of Mining Science and technology 2024年第6期34卷 799-819页

作者： Wei Yao Shuai Wang Bangbiao Wu Ying Xu Kaiwen Xia State Key laboratory of hydraulic engineering Intelligent construction and Operation School of Civil EngineeringTianjin UniversityTianjin 300072China China Railway Design Corporation Tianjin 300308China Institute of Geosafety School of Engineering and TechnologyChina University of GeosciencesBeijing 100083China

Understanding the effects of microwave irradiation and thermal treatment on the dynamic compression and fragmentation properties of rocks is essential to quantify energy consumption in rock *** this study,Fangshan granite(FG)specimens were exposed to microwave irradiation and heat *** damage of FG specimens induced by these two methods was compared using X-ray CT scanning and ultrasonic wave *** temperatures of FG after microwave irradiation and thermal treatment were effectively evaluated using a newly proposed technique.A novelty method for precisely determining the geometric features of fragments is developed to estimate the fragmentation ***,the dynamic uniaxial compressive strength(UCS),the dynamic fragmentation characteristics,and the fragmentation energy of FG after these two pretreatment methods can be reasonably *** noticeable distinction of loading rate effect on the dynamic UCS of FG between these two pretreatment methods is first observed.A relationship is established between the dynamic UCS and the damage induced by microwave irradiation and heat ***,fragmentation energy fan analysis is introduced to accurately compare the fragmentation properties of FG after two pretreatment methods in dynamic compression tests.

关键词： Fangshan granite Dynamic experiments Microwave irradiation Thermal treatment Loading rate Fragmentation

Microstructure development of Ti scaffold by laser powder bed fusion with chemical polishing and its mechanical properties,biocompatibility

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Biosurface and Biotribology 2024年第2期10卷 52-62页

作者： Changfu Lu Jing Chen Teng Ma Yuxin Chen Da Zeng Yiliang Gan Youwen Yang Double Medical technology Inc. XiamenChina Institute of Additive Manufacturing Jiangxi University of Science and TechnologyNanchangChina Key laboratory of construction hydraulic Robots of Anhui Higher Education Institutes Tongling UniversityTonglingChina College of engineering and Applied Science Nanjing UniversityNanjingChina

Titanium(Ti)dental scaffolds are widely used in dental prosthetics due to their excellent mechanical properties and ***,conventional Ti scaffolds manufactured through machining often do not fit perfectly with the bone defect *** powder bed fusion(LPBF)technology enables the personalised manufacturing of custom-made Ti scaffolds.A custom-made Ti scaffold was prepared using LPBF and its surface roughness was improved through chemical *** enhance the surface roughness,a nitric acid mixed solution with a specific composition of HF:HNO_(3):C_(3)H_(6)O_(3)=2:2:3 was *** polishing mechanism was investigated by adjusting the F/Ti ratio to control the formation and dissolution of the oxide *** a result,the surface of the Ti scaffold after polishing exhibited a smooth and flat appearance compared to the LPBF part,with a reduced surface roughness(Ra)of 1.23±0.19μ*** custom-made Ti scaffold also demonstrated favourable mechanical properties,with a bending strength of 335.18±33.62 MPa and stiffness of 2.13±0.21 ***,in vitro cell tests confirmed the excellent biocompatibility of the custom-made Ti *** authors present a feasible strategy for the further clinical application of custom-made Ti scaffolds,offering enhanced surface properties and addressing the limitations of conventional machining methods.

关键词： additive manufacturing dental material property surface roughness

Study on the Load Characteristics of Submerged Body Under Internal Solitary Waves on the Continental Shelf and Slope

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China Ocean engineering 2024年第5期38卷 809-820页

作者： LIU Qian CUI Jian MEI Huan GAO Jun-liang WU Xiang-bai ZHANG Dai-yu ZHANG Rui-rui SHANG Xiao-dong School of Naval Architecture and Ocean engineering Jiangsu University of Science and Technology Key laboratory of port Waterway and Sedimentation Engineering of MOT Nanjing Hydraulic Research Institute State Key laboratory of Tropical Oceanography South China Sea Institute of Oceanology Chinese Academy of Sciences Southern Marine Science and engineering Guangdong laboratory

Based on the high-quality observation data and the numerical simulation, the evolution characteristics of internal solitary waves(ISWs) and the load on the suspend submerged body are studied on the continental shelf and slope separately. The observed ISWs exhibit the first mode depression ISWs. The amplitudes of ISWs on the shelf and slope areas reach 50 m and 80 m, respectively. The upper layer velocity in the westward direction is about 0.8 m/s on the continental shelf and 0.9 m/s on the continental slope during the passing through of ISWs. The lower layer is dominated by the eastward compensating flow. In the vertical direction, the water in front of the wave flows downward, while the water behind the wave flows upward, and the maximum vertical velocity exceeds 0.2 m/s. Numerical simulation results show that the larger the amplitude of ISWs, the larger the load on the submerged body. The force on the submerged body by ISWs is dominated by the vertical force, and the corresponding maximum vertical forces on the continental shelf and slope are-25 kN and-27 kN. The submerged body is subjected to a large counterclockwise moment and the sudden change of the moment will also cause the submerged body to capsize. This paper not only gives a deeper understanding of the characteristics of ISWs from the deep continental slope to the shallow continental shelf, but also has a certain guiding value for the prediction of ISWs and for marine military activities.

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Impact of mica on geotechnical behavior of weathered granitic soil using macro and micro investigations

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Journal of Rock Mechanics and Geotechnical engineering 2024年第6期16卷 2250-2266页

作者： Xianwei Zhang Xinyu Liu Haodong Gao Gang Wang Ran An Zhu Liang State Key laboratory of Geomechanics and Geotechnical engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China School of Civil and hydraulic engineering Huazhong University of Science and TechnologyWuhan430074China College of Urban construction Wuhan University of Science and TechnologyWuhan430065China University of Chinese Academy of Sciences Beijing100049China Guangzhou Urban Planning&Design Survey Research Institute Guangzhou510000China Guangdong Enterprise Key laboratory for Urban Sensing Monitoring and Early WarningGuangzhou510000China

The micaceous weathered granitic soil(WGS)is frequently encountered in civil engineering worldwide,unfortunately little information is available regarding how mica affects the physico-mechanical behaviors of *** study prepares reconstituted WGS with different mica contents by removing natural mica in theWGS,and then mixes it with commercial mica *** geotechnical behavior as well as the microstructures of the mixtures are *** addition of mica enables the physical indices of WGS to be specific combinations of coarser gradation and high permeability but high Atterberg ***,high mica content in WGS was found to be associated with undesirable mechanical properties,including increased compressibility,disintegration,and swelling potential,as well as poor compactability and low effective frictional *** analysis indicates that the influence of mica on the responses of mixtures originates from the intrinsic nature of mica as well as the particle packing being formed *** exists in the mixture as stacks of plates that form a spongy structure with high compressibility and swelling *** among the plates give the soil high water retention and high Atterberg *** pores are also generated by soil particles with bridging packing,which enhances the permeability and water-soil interactions upon *** study provides a microlevel understanding of how mica dominates the behavior of WGS and provides new insights into the effective stabilization and improvement of micaceous soils.

关键词： Weathered granitic soil(WGS) Mica Microstructure Physical properties Mechanical properties Mechanism

Biomedical rare-earth magnesium alloy:Current status and future prospects

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Journal of Magnesium and Alloys 2024年第4期12卷 1260-1282页

作者： Mingli Yang Cheng Chen Dongsheng Wang Yinjin Shao Wenhao Zhou Cijun Shuai Youwen Yang Xinghai Ning Institute of Additive Manufacturing Jiangxi University of Science and TechnologyNanchang 330013China Key laboratory of construction hydraulic Robots of Anhui Higher Education Institutes Tongling UniversityTongling 244061China Department of Rehabilitation Ganzhou People’s HospitalGanzhou 341099China Shaanxi Key laboratory of Biomedical Metallic Materials Northwest Institute for Non-Ferrous Metal ResearchXi’an 710016China State Key laboratory of High Performance Complex Manufacturing Central South UniversityChangsha 410083China School of Mechanical and Electrical engineering Jiangxi University of Science and TechnologyGanzhou 341000China College of engineering and Applied Science Nanjing University210089China

Biomedical magnesium(Mg)alloys have garnered significant attention because of their unique biodegradability,favorable biocompatibility,and suitable mechanical *** incorporation of rare earth(RE)elements,with their distinct physical and chemical properties,has greatly contributed to enhancing the mechanical performance,degradation behavior,and biological performance of biomedical Mg ***,a series of RE-Mg alloys are being designed and investigated for orthopedic implants and cardiovascular stents,achieving substantial and encouraging research *** this work,a comprehensive summary of the state-of-the-art in biomedical RE-Mg alloys is *** physiological effects and design standards of RE elements in biomedical Mg alloys are ***,the degradation behavior and mechanical properties,including their underlying action are studied ***,the preparation techniques and current application status of RE-Mg alloys are ***,we address the ongoing challenges and propose future prospects to guide the development of high-performance biomedical Mg-RE alloys.

关键词： Magnesium alloy Rare earth elements Biodegradation behavior Mechanical performance Biological properties