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The variation in basal channels and basal melt rates of Pine Island Ice Shelf

Acta Oceanologica Sinica 2024年第1期43卷 22-34页

作者： Mingliang Liu Zemin Wang Baojun Zhang Xiangyu Song Jiachun An Chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhan 430079China Key Laboratory of Polar Environment Monitoring and Public Governance(Wuhan university) Ministry of EducationWuhan 430079China School of Civil Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China Key Laboratory of Roads and Railway Engineering Safety Control(shijiazhuang tiedao university) Ministry of EducationShijiazhuang 050043China

In recent years,there has been a significant acceleration in the thinning,calving and retreat of the Pine Island Ice Shelf(PIIS).The basal channels,results of enhanced basal melting,have the potential to significantly impact the stability of the *** this study,we used a variety of remote sensing data,including Landsat,REMA DEM,ICESat-1 and ICESat-2 satellite altimetry observations,and Ice Bridge airborne measurements,to study the spatiotemporal changes in the basal channels from 2003 to 2020 and basal melt rate from 2010 to 2017 of the PIIS under the Eulerian *** found that the basal channels are highly developed in the PIIS,with a total length exceeding 450 *** of the basal channels are ocean-sourced or groundingline-sourced basal channels,caused by the rapid melting under the ice shelf or near the groundingline.A raised seabed prevented warm water intrusion into the eastern branch of the PIIS,resulting in a lower basal melt rate in that *** contrast,a deepsea trough facilitates warm seawater into the mainstream and the western branch of the PIIS,resulting in a higher basal melt rate in the main-stream,and the surface elevation changes above the basal channels of the mainstream and western branch are more *** El Ni?o event in 2015–2016 possibly slowed down the basal melting of the PIIS by modulating wind field,surface sea temperature and depth seawater *** and atmospheric changes were driven by El Ni?o,which can further explain and confirm the changes in the basal melting of the PIIS.

关键词： Pine Island Ice Shelf basal channel basal melt rate digital elevation models(DEMs) satellite altimetry

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On the Polygonal Wear Evolution of Heavy-Haul Locomotive Wheels due to Wheel/Rail Flexibility and Its Mitigation Measures

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 40-61页

作者： Yunfan Yang Feifan Chai Pengfei Liu Liang Ling Kaiyun Wang Wanming Zhai State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu 610031China

Wheel polygonal wear can immensely worsen wheel/rail interactions and vibration performances of the train and track,and ultimately,lead to the shortening of service life of railway *** present,wheel/rail medium-or high-frequency frictional interactions are perceived as an essential reason of the high-order polygonal wear of railway wheels,which are potentially resulted by the flexible deformations of the train/track system or other external *** this work,the effect of wheel/rail flexibility on polygonal wear evolution of heavy-haul locomotive wheels is explored with aid of the long-term wheel polygonal wear evolution simulations,in which different flexible modeling of the heavy-haul wheel/rail coupled system is ***,the mitigation measures for the polygonal wear of heavy-haul locomotive wheels are *** results point out that the evolution of polygonal wear of heavy-haul locomotive wheels can be veritably simulated with consideration of the flexible effect of both wheelset and *** of mixed-line operation of heavy-haul trains and application of multicut wheel re-profiling can effectively reduce the development of wheel polygonal *** research can provide a deep-going understanding of polygonal wear evolution mechanism of heavy-haul locomotive wheels and its mitigation measures.

关键词： Heavy-haul locomotive Wheel polygonal wear Wheel/rail flexibility Long-term polygonal wear evolution Mitigation measures

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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 *** the coupling mechanisms between longitudinal and vertical vehicle dynamics are *** 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 ***,the effectiveness of the proposed control scheme is evaluated through comprehensive tests conducted on a hardware-in-loop(HIL)test *** 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

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Damage effect and progressive failure mechanism of sandstone considering different flaw angles under dynamic loading

Rock Mechanics Bulletin

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Rock Mechanics Bulletin 2024年第1期3卷 81-96页

作者： Dongliang Ji Hui Cheng Hongbao Zhao State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuangChina Key Laboratory of Mechanical Behavior Evolution and Control of Traffic Engineering Structures in Hebei Shijiazhuang Tiedao UniversityShijiazhuangChina School of Energy and Mining Engineering China University of Mining and Technology(Beijing)BeijingChina

In many engineering applications,it is essential to have information about rocks that inherently contain preexisting flaws under dynamic loading *** impact tests are conducted on samples with varying flaw angles using the split Hopkinson pressure bar(SHPB)test system and the Digital Image Correlation system(DIC).The characteristics of the samples after dynamic loading,including dynamic strength,energy dissipation,and fractal fracture,are compared and *** the flaw angle increases,the peak stress and strain exhibit a typical V-shaped pattern,reaching the minimum value at 30,and the initial initiation position shifts from the flaw tips to the middle of the *** modes can be divided into three modes depending on the flaw *** progressive failure process,taking into account the heterogeneity of the rock,is demonstrated by developing an elastic damage constitutive model that uses dynamic compression and tensile tests to parameterize *** the flaw angle increases,the initial damage zone also moves from the flaw tips to the middle of the *** around the hole with redistributed stress are observed,and the failure mechanisms can be explained with the aid of strain energy density(SED).Using fracture mechanics,the analytical solution of stress around the flaw is provided,and the variation of crack initiation angle,stress distribution,and energy dissipation under different flaw angles is theoretically explained,which is in good agreement with the experimental and simulated results.

关键词： Dynamic loading Damage evolution Constitutive model Flaw angle Energy dissipation

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Nonlinear Extrapolation Estimates of π

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 91-108页

作者： Wen-qing Xu Sha-sha Wang Da-chuan Xu Beijing Institute for Scientific and Engineering Computing Beijing University of TechnologyBeijing100124China Department of Mathematics and Statistics California State UniversityLong BeachCalifornia90840USA Department of Mathematics and Physics Shijiazhuang Tiedao UniversityShijiazhuang050043China

The classical Archimedean approximation of π uses the semiperimeter or area of regular polygons inscribed in or circumscribed about a unit circle in R~2 and it is well-known that by using linear combinations of these basic estimates,modern extrapolation techniques can greatly speed up the approximation ***,when n vertices are randomly selected on the circle,the semiperimeter and area of the corresponding random inscribed and circumscribing polygons are known to converge to π almost surely as n→∞,and by further applying extrapolation processes,faster convergence rates can also be achieved through similar linear combinations of the semiperimeter and area of these random *** this paper,we further develop nonlinear extrapolation methods for approximating π through certain nonlinear functions of the semiperimeter and area of such *** focus on two types of extrapolation estimates of the forms χ_n=S_n~αA_n~β and Y_n(p)=(αS_n~p+βA_n~p)~(1/p) where α+β=1,p≠0,and Sn and An respectively represents the semiperimeter and area of a random n-gon inscribed in the unit circle in R~2,and Xn may be viewed as the limit of Y_n(p) when p→*** deriving probabilistic asymptotic expansions with carefully controlled error estimates for Xn and Y_n(p),we show that the choice α=4/3,β=-1/3 minimizes the approximation error in both cases,and their distributions are also asymptotically normal.

关键词： Archimedean polygons random polygons approximations ofπ extrapolation processes asymptotic convergence

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A state-of-the-art review of the development of self-healing concrete for resilient infrastructure

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 151-169页

作者： Dong LU Xi JIANG Yao ZHANG Shaowei ZHANG Guoyang LU Zhen LENG Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China Laboratory of Fire Safety School of Safety Engineering and Emergency ManagementShijiazhuang Tiedao UniversityShijiazhuang 050043China Department of Architecture and Civil Engineering City University of Hong KongHong Kong 999077China

The brittleness of cement composites makes cracks almost inevitable,producing a serious limitation on the lifespan,resilience,and safety of concrete *** address this brittleness,self-healing concrete has been developed for regaining its mechanical and durability properties after becoming cracked,thereby promising sustainable development of concrete *** paper provides a comprehensive review of the latest developments in self-healing *** begins by summarizing the methods used to evaluate the self-healing efficiency of ***,it compares strategies for achieving healing *** then discusses the typical approaches for developing self-healing ***,critical insights are proposed to guide future studies on the development of novel self-healing *** review will be useful for researchers and practitioners interested in the field of self-healing concrete and its potential to improve the durability,resilience,and safety of concrete infrastructure.

关键词： resilient infrastructure sustainable concrete self-healing cracks

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A Cyclic Constitutive Model Based on Crystal Plasticity for Body-Centered Cubic Cyclic Softening Metals

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Acta Mechanica Solida Sinica 2024年第1期37卷 33-42页

作者： Xuehong Ren Wenjie Zhao Shaopu Yang Guilin Wen State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China School of Mechanical Engineering Tianjin Sino-German University of Applied SciencesTianjin 300350China State Key Laboratory of Mechanical Behavior in Traffic Engineering Structure and System Safety Shijiazhuang Tiedao UniversityShijiazhuang 050043China

Under the framework of the small deformation crystal plasticity theory,a crystal plastic cyclic constitutive model for body-centered cubic(BCC)cyclic softening polycrystalline metals is *** constitutive model introduces the isotropic softening rule that includes two different mechanisms:namely softening under monotonic deformation and softening under cyclic deformation on each slip ***,a modified Armstrong-Frederick nonlinear kinematic hardening rule is *** appropriate explicit scale transition rule is selected to extend the single crystal constitutive model to the polycrystalline constitutive *** the model is used to predict the uniaxial and multiaxial ratcheting deformation of BCC axle steel EA4T to verify the rationality of the proposed *** simulation results indicate that the newly established crystal plasticity model can not only describe the cyclic softening characteristics of BCC axle steel EA4T well,but also reasonably describe the evolution laws of uniaxial ratcheting and nonproportional multiaxial ratcheting ***,the established crystal plastic cyclic constitutive model can reasonably predict the ratcheting behavior of BCC single crystal as well.

关键词： Crystal plasticity Constitutive model Softening Ratcheting

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Lateral earth pressure of granular backfills on retaining walls with expanded polystyrene geofoam inclusions under limited surcharge loading

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1388-1397页

作者： Kewei Fan Guangqing Yang Weilie Zou Zhong Han Yang Shen Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing210098China School of Civil Engineering Wuhan UniversityWuhan430072China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang050043China

Existing studies have focused on the behavior of the retaining wall equipped with expanded polystyrene(EPS)geofoam inclusions under semi-infinite surcharge loading rather than limited surcharge *** this paper,the failure mode and the earth pressure acting on the rigid retaining wall with EPS geofoam inclusions and granular backfills(henceforth referred to as EPS-wall),under limited surcharge loading are investigated through two-and three-dimensional model *** testing results show that different from the sliding of almost all the backfill in the EPS-wall under semi-infinite surcharge loading,only an approximately triangular backfill slides in the wall under limited surcharge *** distribution of the lateral earth pressure on the EPS-wall under limited surcharge loading is non-linear,and the distribution changes from the increase of the wall depth to the decrease with the increase of the limited surcharge *** approach based on the force equilibrium of a differential element is developed to predict the lateral earth pressure behind the EPS-wall subjected to limited surcharge loading,and its performance was fully validated by the three-dimensional model tests.

关键词： Retaining wall Expanded polystyrene(EPS)geofoam Limited surcharge loading Lateral earth pressure Model test Prediction

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Comparative analysis of thermodynamic and mechanical responses between underground hydrogen storage and compressed air energy storage in lined rock caverns

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International Journal of Mining Science and Technology 2024年第4期34卷 531-543页

作者： Bowen Hu Liyuan Yu Xianzhen Mi Fei Xu Shuchen Li Wei Li Chao Wei Tao Zhang State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China Key Laboratory of Large Structure Health Monitoring and Control Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Mechanics and Civil Engineering China University of Mining and TechnologyXuzhou 221116China

Underground hydrogen storage(UHS)and compressed air energy storage(CAES)are two viable largescale energy storage technologies for mitigating the intermittency of wind and solar ***,it is meaningful to compare the properties of hydrogen and air with typical thermodynamic storage *** study employs a multi-physical coupling model to compare the operations of CAES and UHS,integrating gas thermodynamics within caverns,thermal conduction,and mechanical deformation around rock *** thermodynamic responses are validated using additional simulations and the field test *** and pressure variations of air and hydrogen within rock caverns exhibit similarities under both adiabatic and diabatic simulation *** reaches higher temperature and pressure following gas charging stage compared to air,and the ideal gas assumption may lead to overestimation of gas temperature and *** steel lining of CAES,the sealing layer(fibre-reinforced plastic FRP)in UHS is prone to deformation but can effectively mitigates stress in the sealing *** CAES,the first principal stress on the surface of the sealing layer and concrete lining is tensile stress,whereas UHS exhibits compressive stress in the same *** present research can provide references for the selection of energy storage methods.

关键词： Underground hydrogen storage Compressed air energy storage Mechanical response Thermodynamic response Lined rock caverns

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基于机器学习的氮掺杂石墨炔力学性能预测

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Science China Materials 2024年第4期67卷 1129-1139页

作者：张存杨博林彭志龙陈少华 Department of Engineering Mechanics Shijiazhuang Tiedao UniversityShijiazhuang 050043China Hebei Key Laboratory of Intelligent Materials and Structures Mechanics Shijiazhuang Tiedao UniversityShijiazhuang 050043China Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijing 100081China Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures Beijing Institute of TechnologyBejing 100081China Hebei Research Center of the Basic Discipline Engineering Mechanics Shijazhuang Tiedao UniversityShijiazhuang 050043China Provincial Collaborative Innovation Center of Mechanics of Intelligent Materials in Hebei Shijiazhuang Tiedao UniversityShijiazhuang 050043China

氮掺杂γ-石墨二炔(N-GDY)因其在能源、电子元器件和催化领域具有重要应用前景而备受关注.研究表明,N-GDY在不同的氮掺杂情况下会表现出迥异的物理化学性质.由于氮掺杂的多样性,N-GDY的理论及应用研究受到了极大的限制.鉴于此,本文采用... 详细信息

氮掺杂γ-石墨二炔(N-GDY)因其在能源、电子元器件和催化领域具有重要应用前景而备受关注.研究表明,N-GDY在不同的氮掺杂情况下会表现出迥异的物理化学性质.由于氮掺杂的多样性,N-GDY的理论及应用研究受到了极大的限制.鉴于此,本文采用鄂维南等人提出的DeepMD方法训练得到了具有第一性原理精度、适用于N-GDY的机器学习势.利用该机器学习势,系统研究了氮掺杂模式对N-GDY力学性能的影响.研究发现,氮原子掺杂会导致N-GDY的抗拉强度降低.在单个碳链上掺杂氮原子时,N-GDY的抗拉强度随着氮原子掺杂位点到苯环的距离变小而减弱.相邻碳链氮原子共掺杂能够使N-GDY表现出更强的各向异性力学特征.本文研究结果对N-GDY在能源存储和柔性设备等领域的潜在应用提供了理论支持,同时也表明了机器学习势在从大规模数据集中学习并预测碳纳米材料复杂力学性质方面的潜力,为纳米材料设计及工程应用具有重要指导作用.

关键词：机器学习力学性能预测氮掺杂碳纳米材料能源存储力学特征第一性原理电子元器件

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