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Reliability-based life-cycle cost seismic design optimization of coastal bridge piers with nonuniform corrosion using different materials

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 209-225页

作者： Wu Xiangtong Yuan Wenting Guo Anxin key lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the ministry of Industry and Information Technology Harbin Institute of TechnologyHarbin 150090China key lab of structures dynamic behavior and control of the ministry of education Harbin Institute of TechnologyHarbin 150090China Institute of Transportation Inner Mongolia UniversityHohhot 010070China

Reinforcement corrosion is the main cause of performance deterioration of reinforced concrete(RC)*** research has been performed to investigate the life-cycle cost(LCC)of coastal bridge piers with nonuniform corrosion using different *** this study,a reliability-based design optimization(RBDO)procedure is improved for the design of coastal bridge piers using six groups of commonly used materials,i.e.,normal performance concrete(NPC)with black steel(BS)rebar,high strength steel(HSS)rebar,epoxy coated(EC)rebar,and stainless steel(SS)rebar(named NPC-BS,NPC-HSS,NPC-EC,and NPC-SS,respectively),NPC with BS with silane soakage on the pier surface(named NPC-Silane),and high-performance concrete(HPC)with BS rebar(named HPC-BS).First,the RBDO procedure is improved for the design optimization of coastal bridge piers,and a bridge is selected to illustrate the ***,reliability analysis of the pier designed with each group of materials is carried out to obtain the time-dependent reliability in terms of the ultimate and serviceability ***,the repair time of the pier is predicted based on the time-dependent reliability ***,the time-dependent LCCs for the pier are obtained for the selection of the optimal design.

关键词： reliability-based design optimization(RBDO) life-cycle cost(LCC) nonuniform corrosion coastal bridge pier repair

Stability and accuracy of central difference method for real-time dynamic substructure testing considering mass participation coefficient

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Earthquake Engineering and Engineering Vibration 2024年第3期23卷 625-636页

作者： Zheng Lichang Xu Guoshan Yang Ge Wang Zhen Yang Kaibo Zheng Zhenyun School of Civil Engineering Harbin Institute of TechnologyHarbin 150090China key lab of structures dynamic behavior and control Ministry of EducationHarbin Institute of TechnologyHarbin 150090China key lab of Intelligent Disaster Mitigation Ministry of Industry and Information TechnologyHarbin 150090China School of Civil Engineering and Architecture Wuhan University of TechnologyWuhan 430070China

For real-time dynamic substructure testing(RTDST),the influence of the inertia force of fluid specimens on the stability and accuracy of the integration algorithms has never been ***,this study proposes to investigate the stability and accuracy of the central difference method(CDM)for RTDST considering the specimen mass participation ***,the theory of the CDM for RTDST is ***,the stability and accuracy of the CDM for RTDST considering the specimen mass participation coefficient are ***,numerical simulations and experimental tests are conducted for verifying the effectiveness of the *** study indicates that the stability of the algorithm is affected by the mass participation coefficient of the specimen,and the stability limit first increases and then decreases as the mass participation coefficient *** most cases,the mass participation coefficient will increase the stability limit of the algorithm,but in specific circumstances,the algorithm may lose its *** stability and accuracy of the CDM considering the mass participation coefficient are verified by numerical simulations and experimental tests on a three-story frame structure with a tuned liquid damper.

关键词： real-time dynamic substructure testing central difference method stability mass participation coefficient tuned liquid damper

Effect of trigger system on experimental dispersion characteristics of active surface wave testing

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 311-318页

作者： Lin Shibin Jeramy C.Ashlock Zhu Liming Qin Zexiang Li Bo Zhu Xingji Zhai Changhai State key laboratory of Precision Blasting Jianghan UniversityWuhan 430056China Hubei key laboratory of Blasting Engineering Jianghan UniversityWuhan 430056China Department of Civil Construction&Environmental EngineeringIowa State UniversityAmesIA 50010USA Wuhan Airport Road Development Co. Ltd.Wuhan 430065China School of Civil and Environmental Engineering Harbin Institute of TechnologyShenzhen 518055China key lab of structures dynamic behavior and control of the ministry of education Harbin Institute of TechnologyHarbin 150090China key lab of Smart Prevention and Mitigation of Civil Engineering Disaster of the ministry of Industry and Information Technology Harbin Institute of TechnologyHarbin 150090China

A trigger system is typically employed in active seismic testing to trigger and synchronize multichannel surface wave data *** effect of the trigger system on the dispersion image of surface waves is empirically known to be negligible,however,theoretical explanation regarding the effect of the trigger system is *** study systematically examines the theory for surface wave dispersion analysis and proves that the effect of the trigger system on a dispersion image is negligible via a solid theoretical ***,based on the new theoretical explanation,an alternative method that uses only the relative phase difference between sensors to extract dispersion characteristics with better conceptual clarity is *** active surface wave testing cases are considered to validate the theory and *** results indicate that(1)an accurate trigger system is not necessary for surface wave data acquisition,and(2)it is unnecessary to assume that the impact point is the generation point of the surface waves for the experimental dispersion analysis.

关键词： site investigation surface waves data acquisition dispersion

Numerical investigation of dynamic characteristics of dual throat nozzle and bypass dual throat nozzle in thrust vectoring starting process

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Chinese Journal of Aeronautics 2024年第10期37卷 184-206页

作者： Yuqi ZHANG Jinglei XU Minglei CAO Ruifeng PAN Shuai HUANG key laboratory of Inlet and Exhaust System Technology of ministry of education Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China State key laboratory of Mechanics and control of Aeronautics and Astronautics structures Nanjing 210016China

The Bypass Dual Throat Nozzle(BDTN)is a novel fluidic Thrust Vectoring(TV)nozzle,it switches to TV state by opening the valve in the *** greatly manipulate the BDTN,the dynamic characteristics in the TV starting process should be *** paper conducts numerical simulations to grasp the variation processes of performances and the flow field evolution of BDTN and Dual Throat Nozzle(DTN).The dynamic responses of TV starting in typical DTN models are investigated at ***,the TV starting processes of BDTN in different Nozzle Pressure Ratio(NPR)conditions are simulated,and the valve opening durations(T)are also *** the expected TV direction is achieved in the DTN,the jet is deflected to the opposite direction at the beginning of the dynamic process,which is called the reverse TV ***,this phenomenon disappears in the *** larger injection width of DTN intensifies unsteady oscillations,and the reverse TV phenomenon is *** the BDTN,T determines the delay degree of performance variations compared to the static results,which is called hysteresis *** NPR=10,the hysteresis affects the final stable performance of *** study analyses the dynamic characteristics in DTN and BDTN,laying a foundation for further design of nozzles and control strategies.

关键词： Dual Throat Nozzle(DTN) Bypass Dual Throat Nozzle(BDTN) dynamic characteristic Thrust vectoring starting process Cavity vortex Hysteresis effect

dynamic Sulfur-Rich Polymers from Elemental Sulfur and Epoxides

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Chinese Journal of Polymer Science 2024年第10期42卷 1479-1487,I0010页

作者： Ke-Xiang Chen Chen-Hui Cui Zhen Li Ting Xu Hao-Qing Teng Zhi-Yuan He Yin-Zhou Guo Xiao-Qing Ming Zhi-Shen Ge Yan-Feng Zhang Tie-Jun Wang School of Chemistry Engineering Research Center of Energy Storage Materials and DevicesMinistry of EducationXi’an Jiaotong UniversityXi’an710049China State key lab for Strength and Vibration of Mechanical structures Department of Engineering MechanicsXi’an Jiaotong UniversityXi’an710049China

Sulfur-containing dynamic polymers had attracted significant attention due to their unique chemical structures with high *** sulfur, an inexpensive industrial waste product, to synthesize dynamic polysulfide polymers through reverse vulcanization has been a notable approach. However, this method required high temperatures and resulted in the release of unpleasant oders. In this study, we presented a robust method for the preparation of sulfur-rich polymers with dynamic polysulfide bonds from elemental sulfur and inexpensive epoxide monomers via a one-pot strategy at the mild room temperature. Different types of polysulfide molecules and polymers were synthesized by reacting various epoxide compounds with sulfur, along with the investigation of their structures and dynamic behaviors. It was noteworthy that the obatined polymers prepared from m-(2,3-epoxypropoxy)-N,N-bis(2,3-epoxypropyl)aniline and elemental sulfur exhibit multiple dynamic behaviors, including polysulfide metathesis and polysulfide-thiol exchange, enabling their rapid stress relaxation, self-healing, reprocessing and degradable properties of the cross-linked polymer. More importantly, the hydroxyl groups at the side chains from epoxide ring opening exhibited potential transesterification. This work provided a facile strategy for designing dynamic sulfur-rich polymers via a mild synthesis route.

关键词： Elemental sulfur Sulfur-containing polymer dynamic covalent bond dynamic polymer

dynamic coupling of ferrihydrite transformation and associated arsenic desorption/redistribution mediated by sulfate-reducing bacteria

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Journal of Environmental Sciences 2024年第1期135卷 39-50页

作者： Wenjing Zhou Huiyan Zhu Shiwen Hu Bowei Zhang Kun Gao Zhi Dang Chongxuan Liu State Environmental Protection key laboratory of Integrated Surface Water-Groundwater Pollution control School of Environmental Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China The key lab of Pollution control and Ecosystem Restoration in Industry Clusters Ministry of EducationSouth China University of TechnologyGuangzhou 510006China

Sulfate-reducing bacteria play an important role in the geochemistry of iron(oxyhydr)oxide and arsenic(As)in natural environments;however,the associated reaction processes are yet to be fully *** this study,batch experiments coupled with geochemical,spectroscopic,microscopic,and thermodynamic analyses were conducted to investigate the dynamic coupling of ferrihydrite transformation and the associated As desorption/redistribution mediated by Desulfovibrio vulgaris(***).The results indicated that *** could induce ferrihydrite transformation via S^(2-)-driven and direct reduction *** the absence of SO_(4)^(2-),*** directly reduced ferrihydrite,and As desorption and re-sorption occurred simultaneously during the partial transformation of ferrihydrite to *** increase in SO_(4)^(2-)loading promoted the S^(2-)-driven reduction of ferrihydrite and accelerated the subsequent mineralogical *** the low and medium SO_(4)^(2-)treatments,ferrihydrite was completely transformed to a mixture of magnetite and mackinawite,which increased the fraction of As in the residual phase and stabilized *** the high SO_(4)^(2-)treatment,although the replacement of ferrihydrite by only mackinawite also increased the fraction of As in the residual phase,22.1%of the total As was released into the solution due to the poor adsorption affinity of As to mackinawite and the conversion of As^(5+)to As^(3+).The mechanisms of ferrihydrite reduction,mineralogy transformation,and As mobilization and redistribution mediated by sulfate-reducing bacteria are closely related to the surrounding SO_(4)^(2-)*** results advance our understanding of the biogeochemical behavior of Fe,S,and As,and are helpful for the risk assessment and remediation of As contamination.

关键词： Sulfate-reducing bacteria Arsenic Ferrihydrite Transformation Redistribution

dynamic response of sandwich panel attached with a double mass-spring-damping system to shallow-buried explosion:Analytical modeling

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Science China(Technological Sciences) 2024年第2期67卷 568-586页

作者： ZHANG DuJiang ZHAO ZhenYu GAO HuiYao LU TianJian State key laboratory of Mechanics and control for Aerospace structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China MIIT key laboratory of Multifunctional Lightweight Materials and structures(MLMS) Nanjing University of Aeronautics and AstronauticsNanjing 210016China

How to ensure the safety of occupants has become a challenge for protective design of armored vehicles against intensive blast *** this study,for armored vehicles subjected to shallow-buried explosions,an analytical model was established to characterize the dynamic performance of an all-metallic sandwich floorboard attached with a double mass-spring-damping system(mimicking seat and occupant),with the former consisting of a front face,a core and a rear *** validation,numerical simulations with the method of finite elements(FE)were *** agreement between analytical predictions and numerical results was *** analytical model was then employed to quantify the effects of explosive mass,yield stress of material make,configurational parameters of sandwich panel,spring stiffness,and damping coefficient on dynamic response of the sandwich panel and double mass-spring-damping *** increasing explosive mass and decreasing yield stress of material make,the peak displacements of rear face,seat and occupant were all found to *** core relative density was increased,these peak displacements also increased when the ratio of face thickness to core height was relatively *** the ratio of face thickness to core height led to increased peak accelerations of seat and *** peak displacement of rear face was insensitive to the increase of either spring stiffness or damping coefficient,while the peak acceleration of occupant increased with increasing spring *** increasing the damping coefficient between the rear face and seat or that between the seat and occupant or both,the peak acceleration of occupant *** occupant safety duly considered,the proposed analytical model provides useful guidance for designing high-performance protective structures for armored vehicles subjected to intensive blast loadings.

关键词： analytical model shallow-buried explosion sandwich panel occupant safety mass-spring-damping system

3D nano-printed geometric phase metasurfaces for generating accelerating beams with complex amplitude manipulation

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 86-95页

作者： Tianchen Tang Saima Kanwal Yongzheng Lu Yuelong Li Shuangbao Wu Lei Chen Ziheng Qian Zhouyu Xie Jing Wen Dawei Zhang Research Center of Optical Instrument and System Ministry of Education and Shanghai Key Lab of Modern Optical SystemUniversity of Shanghai for Science and TechnologyShanghai 200093China

Metasurface,a forefront in emerging optical devices,has demonstrated remarkable potential for complex amplitude manipulation of light ***,prevailing approaches face challenges in spatial resolution and complexities associated with integrating dynamic phases,impeding the simplified design and reproducible fabrication of ***,we introduce an innovative approach for complex amplitude modulation within 3D nano-printed geometric phase *** approach enables the generation of self-accelerating beams by encoding amplitude through phase-only manipulation,achieving high spatial ***,this method circumvents the conventional need to adjust the geometric parameters of metasurface unit structures for amplitude manipulation,offering a streamlined and efficient route for design and fabrication *** novel methodology holds promise for expedited and low-cost manufacturing of complex amplitude manipulation metasurfaces.

关键词： metasurface complex amplitude manipulation geometric phase 3D nano-printing Airy beam accelerating parabolic beam

Development of Wheel-Legged Biped Robots:A Review

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Journal of Bionic Engineering 2024年第2期21卷 607-634页

作者： Xuefei Liu Yi Sun Shikun Wen Kai Cao Qian Qi Xiaoshu Zhang Huan Shen Guangming Chen Jiajun Xu Aihong Ji lab of Locomotion Bioinspiration and Intelligent Robots College of Mechanical and Electrical EngineeringNanjing University of Aeronautics and Astronautics29 Yudao StreetNanjing210016China State key laboratory of Mechanics and control for Aerospace structures Nanjing University of Aeronautics and AstronauticsNanjing210016China

The wheel-legged biped robot is a typical ground-based mobile robot that can combine the high velocity and high efficiency pertaining to wheeled motion and the strong,obstacle-crossing performance associated with legged *** robots have gradually exhibited satisfactory application potential in various harsh scenarios such as rubble rescue,military operations,and wilderness ***-legged biped robots are divided into four categories according to the open–close chain structure forms and operation task modes,and the latest technology research status is summarized in this *** hardware control system,control method,and application are analyzed,and the dynamic balance control for the two-wheel,biomimetic jumping control for the legs and whole-body control for integrating the wheels and legs are *** summary,it is observed that the current research exhibits problems,such as the insufficient application of novel materials and a rigid–flexible coupling design;the limited application of the advanced,intelligent control methods;the inadequate understanding of the bionic jumping mechanisms in robot legs;and the insufficient coordination ability of the multi-modal motion,which do not exhibit practical application for the wheel-legged biped ***,this study discusses the key research directions and development trends for the wheel-legged biped robots.

关键词： Wheel-legged biped robot Wheeled motion Legged motion control strategy