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Anticipating the lifespan: Predicting the durability of an anode-supported solid oxide fuel cell short stack over 50,000 h

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Progress in Natural Science:Materials International 2024年第3期34卷 606-613页

作者： Muhammad Zubair Khan Amjad Hussain Seung-Bok Lee Tak-Hyoung Lim Rak-Hyun Song Department of Materials Science & Engineering Pak-Austria Fachhochschule: Institute of Applied Sciences and Technology Hydrogen Energy research division Korea Institute of Energy Research Department of Advanced Energy and system Engineering Korea University of Science and Technology (UST)

In the present study, the operational lifetime of a solid oxide fuel(SOFC) short stack is predicted by investigating the performance degradation of both the short stack and its cells throughout 1000 h at 800°C. The short stack and integral cell voltages are continuously measured during the long-term test, with electrochemical impedance spectroscopy(EIS) conducted every 200 h. The short stack voltage decreased rapidly for the initial 200–300 h and afterwards, it decreased at a slow rate due to the increase in the Ohmic and polarization resistances in the same manner. Scanning electron microscopy results show that there is no delamination or cracking among constituent layers of the short-stack cells. The single degradation effects of the Ni coarsening in the anode, cation migration and surface segregation in cathode and oxide scale growth in metallic interconnect mesh are successfully integrated into a comprehensive lifetime prediction model. The experimentally measured voltage degradation data of the short stack fits well with the developed mathematical model and allows the successful prediction of the lifetime up to 50,000 h.

关键词： Degradation Impedance Lifetime SOFC Stack

Development of vehicle-recognition method on water surfaces using LiDAR data:SPD^(2)(spherically stratified point projection with diameter and distance)

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Defence Technology（防务技术） 2024年第6期36卷 95-104页

作者： Eon-ho Lee Hyeon Jun Jeon Jinwoo Choi Hyun-Taek Choi Sejin Lee The Department of Mechanical Engineering Kongju National University1223-24 Cheonan-daeroCheonan 31080Republic of Korea Ocean system Engineering research division Korea Research Institute of Ships and Ocean Engineering(KRISO)Daejeon 34103Republic of Korea The division of Mechanical&Automotive Engineering Kongju National University1223-24 Cheonan-daeroCheonan 31080Republic of Korea

Swarm robot systems are an important application of autonomous unmanned surface vehicles on water *** monitoring natural environments and conducting security activities within a certain range using a surface vehicle,the swarm robot system is more efficient than the operation of a single object as the former can reduce cost and save *** is necessary to detect adjacent surface obstacles robustly to operate a cluster of unmanned surface *** this purpose,a LiDAR(light detection and ranging)sensor is used as it can simultaneously obtain 3D information for all directions,relatively robustly and accurately,irrespective of the surrounding environmental *** the GPS(global-positioning-system)error range exists,obtaining measurements of the surface-vessel position can still ensure stability during platoon *** this study,a three-layer convolutional neural network is applied to classify types of surface *** aim of this approach is to redefine the sparse 3D point cloud data as 2D image data with a connotative meaning and subsequently utilize this transformed data for object classification ***,we have proposed a descriptor that converts the 3D point cloud data into 2D image *** use this descriptor effectively,it is necessary to perform a clustering operation that separates the point clouds for each *** developed voxel-based clustering for the point cloud ***,using the descriptor,3D point cloud data can be converted into a 2D feature image,and the converted 2D image is provided as an input value to the *** intend to verify the validity of the proposed 3D point cloud feature descriptor by using experimental data in the ***,we explore the feasibility of real-time object classification within this framework.

关键词： Object classification Clustering 3D point cloud data LiDAR(light detection and ranging) Surface vehicle

A simulation-based software to support the real-time operational parameters selection of tunnel boring machines

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Underground Space 2024年第1期14卷 176-196页

作者： Yaman Zendaki Ba Trung Cao Abdullah Alsahly Steffen Freitag Gunther Meschke Institute for structural Mechanics Ruhr University BochumBochum 44801Germany Institute for structural Analysis Karlsruhe Institute of TechnologyKarlsruhe 76131Germany

With the fact that the main operational parameters of the construction process in mechanized tunneling are currently selected based on monitoring data and engineering experience without exploiting the advantages of computer methods,the focus of this work is to develop a simulation-based real-time assistant system to support the selection of operational *** choice of an appropriate set of these parameters(i.e.,the face support pressure,the grouting pressure,and the advance speed)during the operation of tunnel boring machines(TBM)is determined by evaluating different tunneling-induced soil-structure interactions such as the surface settlement,the associated risks on existing structures and the tunnel lining *** evaluate soil-structure behavior,an advanced process-oriented numerical simulation model based on the finite cell method is *** enable the real-time prediction capability of the simulation model for a practical application during the advancement of TBMs,surrogate models based on the Proper Orthogonal Decomposition and Radial Basis Functions(POD-RBF)are *** proposed approach is demonstrated through several synthetic numerical examples inspired by the data of real tunnel *** developed methods are integrated into a user-friendly application called SMART to serve as a support platform for tunnel engineers at construction *** to each user adjustment of the input parameters,i.e.,each TBM driving scenario,approximately two million outputs of soil-structure interactions are quickly predicted and visualized in seconds,which can provide the site engineers with a rough estimation of the impacts of the chosen scenario on structural responses of the tunnel and above ground structures.

关键词： Numerical simulation Surrogate model Real-time prediction Proper orthogonal decomposition Radial basis functions TBM operation Smart construction

Development of multi-functional anchorage support dynamic-static coupling performance test system and its application

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International Journal of Mining Science and Technology 2024年第3期34卷 339-349页

作者： Qi Wang Shuo Xu Bei Jiang Chong Zhang Zhe Sun Jingxuan Liu Cailin Jiao State Key Laboratory for Tunnel Engineering China University of Mining&Technology-BeijingBeijing 100083China research Center of Geotechnical and structural Engineering Shandong UniversityJinan 250061China

In underground engineering with complex conditions,the bolt(cable)anchorage support system is in an environment where static and dynamic stresses coexist,under the action of geological conditions such as high stresses and strong disturbances and construction conditions such as the application of high *** is essential to study the support components performance under dynamic-static coupling *** on this,a multi-functional anchorage support dynamic-static coupling performance test system(MAC system)is developed,which can achieve 7 types of testing functions,including single component performance,anchored net performance,anchored rock performance and so *** bolt and cable mechanical tests are conducted by MAC system under different prestress *** results showed that compared to the non-prestress condition,the impact resistance performance of prestressed bolts(cables)is significantly *** the prestress range of 50–160 k N,the maximum reduction rate of impact energy resisted by different types of bolts is 53.9%–61.5%compared to non-prestress *** the prestress range of 150–300 k N,the impact energy resisted by high-strength cable is reduced by76.8%–84.6%compared to non-prestress *** MAC system achieves dynamic-static coupling performance test,which provide an effective means for the design of anchorage support system.

关键词： Anchorage support system Development of test system Dynamic-static coupling test Combined stress

Equivalent linear model for seismic damage evaluation of single-degree-of-freedom systems representing reinforced concrete structures considering cyclic degradation behavior

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Earthquake Engineering and Engineering Vibration 2024年第3期23卷 637-648页

作者： Lulu Yan Ding-Hao Yu research Center for Geotechnical and structural Engineering Technology of Liaoning Province Dalian UniversityDalian116622China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China

In this study,a novel equivalent damping ratio model that is suitable for reinforced concrete(RC)structures considering cyclic degradation behavior is developed,and a new equivalent linearization analysis method for implementing the proposed equivalent damping ratio model for use in seismic damage evaluation is *** this end,Ibarra’s peak-oriented model,which incorporates an energy-based degradation rule,is selected for representing hysteretic behavior of RC structure,and the optimized equivalent damping for predicting the maximum displacement response is presented by using the empirical method,in which the effect of cyclic degradation is ***,the relationship between the hysteretic energy dissipation of the inelastic system and the elastic strain energy of the equivalent linear system is established so that the proposed equivalent linear system can be directly integrated with the Park-Ang seismic model to implement seismic damage *** to the simplicity of the equivalent linearization method,the proposed method provides an efficient and reliable way of obtaining comprehensive insight into the seismic performance of RC *** verification demonstrates the validity of the proposed method.

关键词： degrading system equivalent linear system equivalent damping seismic damage RC structures

Experimental and numerical studies on buckling and post-buckling behavior of T-stiffened variable stiffness panels

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Chinese Journal of Aeronautics 2024年第10期37卷 459-470页

作者： Yan HUANG Yahui ZHANG Bin KONG Jiefei GU Zhe WANG Puhui CHEN State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China AVIC Aviation Power Control system research Institute Wuxi 214063China Chengdu Aircraft Design and research Institute Aviation Industry Corporation of ChinaChengdu 610091China School of Mechanical Engineering Jiangnan UniversityWuxi 214122China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China China National Key Laboratory of Strength and structural Integrity Aircraft Strength Research Institute of ChinaXi’an 710065China

Currently,experimental research on variable stiffness design mainly focuses on *** ensure adaptability in practical application,it is imperative to conduct a systematic study on stiffened variable stiffness structures,including design,manufacture,experiment,and *** on the minimum curvature radius and process schemes,two types of T-stiffened panels were designed and *** compression tests have been carried out and the results indicate that the buckling load of variable stiffness specimens is increased by 26.0%,while the failure load is decreased by 19.6%.The influence mechanism of variable stiffness design on the buckling and failure behavior of T-stiffened panels was explicated by numerical *** primary reason for the reduced strength is the significantly increased load bearing ratio of *** experimental investigations of stiffened variable stiffness structures are very rare,this study can be considered a reference for future work.

关键词： Variable stiffness composite Buckling Post-buckling Finite element method Stiffened panels

REMnO3（RE=Pr,Nd,Sm,Eu,Gd） perovskite as efficient catalysts for oxygen reduction reaction

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Journal of Rare Earths 2024年第11期42卷 2078-2087页

作者： Rakesh Ranjan Mahalik Siba Soren Ipsha Hota A.K.Debnath K.P.Muthe Purnendu Parhi Department of Chemistry Ravenshaw University Technical Physics division Bhabha Atomic Research Centre

Rare earth metal based perovskite emerges as important catalytic material for energy production and *** ABO3type materials are now the focus of research in the field of oxygen reduction and evolution ***,in this work we evaluated the oxygen reduction properties of the synthesized one-dimensional REMnO3（RE=Pr,Nd,Sm,Eu and Gd）.The one-dimensional REMnO3prepared by the hydrothermal synthesis route results in pure phase perovskite on *** perovskite was characte rized with X-ray diffraction,Fourier transform-infrared（FT-IR）,field emission-scanning electron microscopy（FE-SEM）,transmission electron microscopy（TEM） and X-ray photoelectron spectroscopy（XPS）.The oxygen reduction reaction activities were investigated with the help of electrochemical workstation that consists of three-electrode system immersed in 0.1 mol/L KOH electrolyte solution saturated with *** Koutechy-Levich plot obtained from rotating ring disk electrode shows all the prepared catalysts follow 4e-processes during oxygen *** effect of "A" site cation variation in REMnO3 on oxygen reduction reaction is ***3showed better onset potential for oxygen reduction reaction among the prepared rare earth ***3having high RE:Mn ratio（A-site rich co mpositions） promotes oxygen reduction reaction（ORR） *** the perovs kites showed good oxygen reduction property with high stability and methanol tolerance.

关键词： Electrocatalytic activity Oxygen reduction reaction (ORR) Perovskite Rare earths REMnO3 SmMnO3

Application of CFD and FEA Coupling to Predict structural Dynamic Responses of A Trimaran in Uni-and Bi-Directional Waves

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China Ocean Engineering 2024年第1期38卷 81-92页

作者： LIAO Xi-yu XIA Jin-song CHEN Zhan-yang TANG Qin ZHAO Nan ZHAO Wei-dong GUI Hong-bin Marine Design&research Institute of China Shanghai 200011China Ship Structure division China Ship Scientific Research CenterWuxi 214082China College of Ocean Engineering Harbin Institute of TechnologyWeihaiWeihai 264209China State Key Laboratory of structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China School of Foreign Studies Jiangnan UniversityWuxi 214122China

To predict the wave loads of a flexible trimaran in different wave fields,a one-way interaction numerical simulation method is proposed by integrating the fluid solver(Star-CCM+)and structural solver(Abaqus).Differing from the existing coupled CFD-FEA method for monohull ships in head waves,the presented method equates the mass and stiffness of the whole ship to the hull shell so that any transverse and longitudinal section stress of the hull in oblique waves can be ***,verification study and sensitivity analysis are carried out by comparing the trimaran motions using different mesh sizes and time step *** on the wave elevation of uni-and bi-directional waves is also carried *** a comprehensive analysis on the structural responses of the trimaran in different uni-directional regular wave and bi-directional cross sea conditions is carried out,***,the differences in structural response characteristics of trimaran in different wave fields are *** results show that the present method can reduce the computational burden of the two-way fluid-structure interaction simulations.

关键词： CFD-FEA fluid-structure coupling structural responses trimaran bi-directional cross sea

Comparison of the performance and dynamics of the asymmetric single-sided and symmetric double-sided vibro-impact nonlinear energy sinks with optimized designs

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International Journal of Mechanical system Dynamics 2024年第3期4卷 303-316页

作者： Petro Lizunov Olga Pogorelova Tetyana Postnikova Department of Constructive Mechanics Kyiv National University of Construction and ArchitectureKyivUkraine research Institute of structural Mechanics Kyiv National University of Construction and ArchitectureKyivUkraine

The operation of symmetric double-sided and asymmetric single-sided vibro-impact nonlinear energy sinks(DSVI NES and SSVI NES)is considered in this *** methodology of optimization procedures is *** is emphasized that the execution of optimization procedures is ambiguous,allows for a great deal of arbitrariness,and requires experience and intuition on the part of the *** are a lot of damper parameter sets providing similar attenuation of the primary structure(PS)*** is shown that the efficiency of such mitigation for both VI NES types with optimized parameters is ***,their dynamic behavior differs *** system with the attached DSVI NES exhibits calm dynamics with periodic motion and symmetrical bilateral impacts on both *** system with attached SSVI NES exhibits rich complex dynamics when the exciting force frequency is *** modes of different periodicity with different numbers of asymmetric impacts per cycle on the PS directly and on the obstacle alternate with various irregular regimes,namely,chaotic mode,intermittency,and crisis-induced *** regions of bilateral impacts are narrow and located near resonance;they are narrower for a system with an attached DSVI *** a system with an attached SSVI NES,there are wider areas of asymmetric unilateral impacts.

关键词： vibro-impact damper nonlinear energy sink single-sided double-sided vibrations mitigation optimization