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China Ocean engineering 2024年第3期38卷 394-407页

作者： HU Ze-bo LIU Zhen LI Peng GUO Hai-yan REN Xiao-hui HOU Hao HAO Lian-hong College of Civil engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China Qingdao Key Laboratory of marine Civil engineering Materials and structures Qingdao 266590China College of engineering Ocean University of ChinaQingdao 266100China

In order to study the response law of vortex-induced vibration(VIV)of marine risers under the combined action of roughness and interference effects,and to reveal the coupling mechanism of roughness and interference effects on the riser,a VIV experiment of rough risers in tandem arrangement was conducted in a wave−current combined flume.The experiment characterized the risers’roughness by arranging different specifications of attachments on the surface of the risers.Three rough risers with different roughness and smooth risers were arranged in tandem arrangement,with the rough risers arranged downstream.The experimental results indicate that the suppression of the attachments on the downstream risers’vibration are more significant both in the CF and IL directions as the reduced velocity increases.For the downstream riser,the amplitude response of rough riser is more significantly weakened compared with the smooth one at high reduced velocity.For the upstream risers,changes in the roughness and spacing ratio have an impact on their‘lock-in’region.When the roughness of downstream risers is relatively large(0.1300)and the spacing between risers is small(S/D=4.0),the reduced velocity range of‘lock-in’region in the CF direction of upstream risers is obviously expanded,and the displacement in the‘lock-in’region is severer.

关键词： marine riser vortex-induced vibration tandem arrangement roughness interference effect

Experimental Study on Vortex-Induced Vibration of Rough Risers with Coupling Interference Effect Under Side-by-Side Arrangement

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China Ocean engineering 2024年第1期38卷 18-28页

作者： HU Ze-bo LIU Zhen LI Peng GUO Hai-yan WANG Shu-bing REN Xiao-hui HOU Hao WANG Ye-shuo College of Civil engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China Qingdao Key Laboratory of marine Civil engineering Materials and structures Qingdao 266590China College of engineering Ocean University of ChinaQingdao 266100China CHEC Dredging Co. LtdShanghai 200136China

A vortex-induced vibration(VIV)experiment of rough risers with coupling interference effect under a side-by-side arrangement was carried out in a wave-current combined flume.The roughness of the riser was characterized by arranging different specifications of surface attachments on the surface of the riser.Rough risers with three different roughnesses were arranged side by side with smooth risers to explore the VIV response of the riser under the combined action of roughness and interference effect,and to reveal the coupling mechanism between roughness and interference effect.The experimental results show that,compared with that of a smooth riser,the VIV of a rough riser under the coupling interference effect has a wider"lock-in"region,and the displacement decreases more significantly at a high reduced velocity,which is more likely to excite higher-order modes and frequency responses.In addition,the displacement response and frequency response of the smooth riser are not significantly affected by wake interference from the rough riser,which is caused by the decrease of the wake region due to the delay of the boundary layer separation point of the rough riser.

关键词： marine riser vortex-induced vibration side-by-side arrangement roughness interference effect

A novel efficient energy absorber with free inversion of a metal foam-filled circular tube

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 1-14页

作者： Jianxun ZHANG Jinwen BAI State Key Laboratory for Strength and Vibration of Mechanical structures School of Aerospace EngineeringXi'an Jiaotong UniversityXi'an 710049China

In this paper, a novel efficient energy absorber with free inversion of a metal foam-filled circular tube(MFFCT) is designed, and the axial compressive behavior of the MFFCT under free inversion is studied analytically and numerically. The theoretical analysis reveals that the energy is mainly dissipated through the radial bending of the metal circular tube, the circumferential expansion of the metal circular tube, and the metal filled-foam compression. The principle of energy conservation is used to derive the theoretical formula for the minimum compressive force of the MFFCT over free inversion under axial loading. Furthermore, the free inversion deformation characteristics of the MFFCT are analyzed numerically. The theoretical steady values are found to be in good agreement with the results of the finite element(FE) analysis. The effects of the average diameter of the metal tube, the wall thickness of the metal tube, and the filled-foam strength on the free inversion deformation of the MFFCT are considered. It is observed that in the steady deformation stage, the load-carrying and energy-absorbing capacities of the MFFCT increase with the increase in the average diameter of the metal tube, the wall thickness of the metal tube, or the filled-foam strength. The specific energy absorption(SEA) of free inversion of the MFFCT is significantly higher than that of the metal tube alone.

关键词： metal foam-filled circular tube(MFFCT) free inversion load-carrying capacity energy absorption

Construct a 3D microsphere of HMX/B/Al/PTFE to obtain the high energy and combustion reactivity

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Defence Technology（防务技术） 2024年第2期32卷 45-54页

作者： Jian Wang Jie Chen Yaofeng Mao Yongjun Deng Wei Cao Fude Nie Jun Wang Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621999PR China Shock and Vibration of engineering Materials and structures Key Lab of Sichuan Province Mianyang 621010PR China

Metal(aluminum and boron)based energetic materials have been wildly applied in various fields including aerospace,explosives and micro-devices due to their high energy density.Unfortunately,the low combustion efficiency and reactivity of metal fuels,especially boron(B),severely limit their practical applications.Herein,multi-component 3D microspheres of HMX/B/Al/PTFE(HBA)have been designed and successfully prepared by emulsion and solvent evaporation method to achieve superior energy and combustion reactivity.The reactivity and energy output of HBA are systematically measured by ignitionburning test,constant-volume explosion vessel system and bomb calorimetry.Due to the increased interfacial contact and reaction area,HBA shows higher flame propagation rate,faster pressurization rate and larger combustion heat of 29.95 cm/s,1077 kPa/s,and 6164.43 J/g,which is 1.5 times,3.5 times,and 1.03 times of the physical mixed counterpart(HBA-P).Meanwhile,HBA also shows enhanced energy output and reactivity than 3D microspheres of HMX/B/PTFE(HB)resulting from the high reactivity of Al.The reaction mechanism of 3D microspheres is comprehensively investigated through combustion emission spectral and thermal analysis(TG-DSC-MS).The superior reactivity and energy of HBA originate from the surface etching of fluorine to the inert shell(Al_(2)O_(3) and B_(2)O_(3))and the initiation effect of Al to B.This work offers a promising approach to design and prepare high-performance energetic materials for the practical applications.

关键词： HMX/B/Al/PTFE 3D microspheres Surface etching Reaction mechanism

Layered metastructure containing freely-designed local resonators for wave attenuation

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Defence Technology（防务技术） 2024年第2期32卷 23-31页

作者： Yu Li Huguang He Jiang Feng Hailong Chen Fengnian Jin Hualin Fan State Key Laboratory for Disaster Prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing 210007China Rocket Force University of engineering Xi'an 710025China Henan International Joint Laboratory of Dynamics of Impact and Disaster of engineering structures Department of Civil EngineeringNanyang Institute of TechnologyNanyang 473004China Guangxi Key Laboratory of Disaster Prevention and engineering Safety and Key Laboratory of Disaster Prevention and Structural Safety of Ministry of EducationCollege of Civil Engineering and ArchitectureGuangxi UniversityNanning 530004China Research Center of Lightweight structures and Intelligent Manufacturing State Key Laboratory of Mechanics and Control of Mechanical StructuresNanjing University of Aeronautics and AstronauticsNanjing 210016China

Combining periodic layered structure with three-dimensional cylindrical local resonators,a hybrid metastructure with improved wave isolation ability was designed and investigated through theoretical and numerical approaches.The metastructure is composed of periodic rubber layers and concrete layers embedded with three-dimensional resonators,which can be freely designed with multi local resonant frequencies to attenuate vibrations at required frequencies and widen the attenuation bandgap.The metastructure can also effectively attenuate seismic responses.Compared with layered rubber-based structures,the metastructure has more excellent wave attenuation effects with greater attenuation and wider bandgap.

关键词： Layered metastructure Local resonator Wave attenuation

Aerodynamic optimization of an adaptive flap for next-generation green aircraft

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Chinese Journal of Aeronautics 2024年第2期37卷 100-122页

作者： Tianlong LIN Rosario PECORA Danilo CILIBERTI Wei XIA Shuling HU State Key Laboratory for Strength and Vibration of Mechanical structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an 710049China Deparment of Industrial engineering Aerospace DivisionUniversity of Naples"FEDERICO II"Napoli 80125Italy

Adaptive,morphing flaps are taking ever-increasing attention in civil aviation thanks to the expected benefits this technology can bring at the aircraft level in terms of high-lift performance improvement and related fuel burnt reduction per flight.Relying upon morphing capabilities,it is possible to fix a unique setting for the flap and adapt the flap shape to match the aerodynamic requirements for take-off or landing.The proper morphed shapes can assure better high-lift performances than those achievable by referring to a conventional flap.Moreover,standing the unique flap setting for take-off and landing,a dramatic simplification of the flap deployment systems may be achieved.As a consequence of this simplification,the deployment system can be fully hosted in the wing,thus avoiding under-wing nacelles with significantly better aerodynamics and fuel consumption.The first step for a rational design of an adaptive flap consists in defining the target morphed shapes and the unique optimal flap setting in the take-off and landing phases.In this work,aerodynamic optimization analyses are carried out to determine the best flap setting and related morphed shapes in compliance with the take-off and landing requirements of a reference civil transport aircraft.Four different initial conditions are adopted to avoid the optimization falling into local optima,thus obtaining four groups of optimal candidate configurations.After comparing each candidate’s performance through 2D and 3D simulations,the optimal configuration has been selected.2D simulations show that the optimal configuration is characterized by a maximum lift increase of 31.92%in take-off and 9.04%in landing.According to 3D simulations,the rise in maximum lift equals 22.26%in take-off and 3.50%in landing.Numerical results are finally verified through wind tunnel tests,and the aerodynamic mechanism behind the obtained improvements is explained by carefully analyzing the flow field around the flap.

关键词： Morphing wings High-lift system Adaptive flap Computational Fluid Dynamics(CFD) Wind tunnel tests

Integrated Active Suspension and Anti-Lock Braking Control for Four-Wheel-Independent-Drive Electric Vehicles

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Chinese Journal of Mechanical engineering 2024年第1期37卷 87-98页

作者： Ze Zhao Lei Zhang Xiaoling Ding Zhiqiang Zhang Shaohua Li Liang Gu National engineering Research Center for Electric Vehicles Beijing Institute of TechnologyBeijing 100081China State Key Laboratory of Mechanical Behavior and System Safety of Traffic engineering structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China

This paper presents an integrated control scheme for enhancing the ride comfort and handling performance of a four-wheel-independent-drive electric vehicle through the coordination of active suspension system(ASS)and anti-lock braking system(ABS).First,a longitudinal-vertical coupled vehicle dynamics model is established by integrating a road input model.Then the coupling mechanisms between longitudinal and vertical vehicle dynamics are analyzed.An ASS-ABS integrated control system is proposed,utilizing an H∞controller for ASS to optimize load transfer effect and a neural network sliding mode control for ABS implementation.Finally,the effectiveness of the proposed control scheme is evaluated through comprehensive tests conducted on a hardware-in-loop(HIL)test platform.The HIL test results demonstrate that the proposed control scheme can significantly improve the braking performance and ride comfort compared to conventional ABS control methods.

关键词： Four-wheel-independent-drive electric vehicles Active suspension system(ASS) Anti-lock braking system(ABS) Vertical-longitudinal vehicle dynamics

Fatigue Crack Propagation Law of Corroded Steel Box Girders in Long Span Bridges

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Computer Modeling in engineering & Sciences 2024年第7期140卷 201-227页

作者： Ying Wang Longxiao Chao Jun Chen Songbai Jiang Key Laboratory of Concrete and Prestressed Concrete structures of Ministry of Education School of Civil EngineeringSoutheast UniversityNanjing211189China Jiangsu Provincial engineering Construction Standard Station Nanjing210036China

In order to investigate the fatigue performance of orthotropic anisotropic steel bridge decks,this study realizes the simulation of the welding process through elastic-plastic finite element theory,thermal-structural sequential coupling,and the birth-death element method.The simulated welding residual stresses are introduced into the multiscale finite element model of the bridge as the initial stress.Furthermore,the study explores the impact of residual stress on crack propagation in the fatigue-vulnerable components of the corroded steel box girder.The results indicate that fatigue cracks at the weld toe of the top deck,the weld root of the top deck,and the opening of the transverse diaphragm will not propagate under the action of a standard vehicle load.However,the inclusion of residual stress leads to the propagation of these cracks.When considering residual stress,the fatigue crack propagation paths at the weld toe of the transverse diaphragm and the U-rib weld toe align with those observed in actual bridges.In the absence of residual stress,the cracks at the toe of the transverse diaphragm with a 15%mass loss rate are categorized as type I cracks.Conversely,when residual stress is considered,these cracks become I-II composite cracks.Residual stress significantly alters the cumulative energy release rate of the three fracturemodes.Therefore,incorporating the influence of residual stress is essential when assessing the fatigue performance of corroded steel box girders in long-span bridges.

关键词： Residual stress crack propagation corroded steel box girder cumulative energy release rate

Pulses in ground motions identified through surface partial matching and their impact on seismic rocking consequence

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Earthquake engineering and engineering Vibration 2024年第1期23卷 35-50页

作者： Tang Yuchuan Wang Jiankang Wu Gang School of Civil engineering Southeast UniversityKey Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of EducationNanjing 211102China National and Local Joint engineering Research Center for Intelligent Construction and Maintenance Nanjing 211102China

In seismology and earthquake engineering,it is fundamental to identify and characterize the pulse-like features in pulse-type ground motions.To capture the pulses that dominate structural responses,this study establishes congruence and shift relationships between response spectrum surfaces.A similarity search between spectrum surfaces,supplemented with a similarity search in time series,has been applied to characterize the pulse-like features in pulse-type ground motions.The identified pulses are tested in predicting the rocking consequences of slender rectangular blocks under the original ground motions.Generally,the prediction is promising for the majority of the ground motions where the dominant pulse is correctly identified.

关键词： velocity pulse ground motion surface similarity rocking overturning

Indentation behavior of a semi-infinite piezoelectric semiconductor under a rigid flat-ended cylindrical indenter

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 649-662页

作者： Shijing GAO Lele ZHANG Jinxi LIU Guoquan NIE Weiqiu CHEN State Key Laboratory of Mechanical Behavior and System Safety of Traffic engineering structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Mechanical engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China Hebei Key Laboratory for Mechanics of Intelligent Materials and structures Department of Engineering MechanicsShijiazhuang Tiedao UniversityShijiazhuang 050043China State Key Laboratory of Computer Aided Design and Computer Graphics Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceDepartment of Engineering MechanicsZhejiang UniversityHangzhou 310027China

This paper theoretically studies the axisymmetric frictionless indentation of a transversely isotropic piezoelectric semiconductor(PSC)half-space subject to a rigid flatended cylindrical indenter.The contact area and other surface of the PSC half-space are assumed to be electrically insulating.By the Hankel integral transformation,the problem is reduced to the Fredholm integral equation of the second kind.This equation is solved numerically to obtain the indentation behaviors of the PSC half-space,mainly including the indentation force-depth relation and the electric potential-depth relation.The results show that the effect of the semiconductor property on the indentation responses is limited within a certain range of variation of the steady carrier concentration.The dependence of indentation behavior on material properties is also analyzed by two different kinds of PSCs.Finite element simulations are conducted to verify the results calculated by the integral equation technique,and good agreement is demonstrated.

关键词： piezoelectric semiconductor(PSC) insulating indenter electromechanical response singular integral equation finite element simulation