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SSRN 2023年

作者： Xu, Shuo Yan, Zhanyou Zhao, Li School of Civil Engineering Shijiazhuang Tiedao University Hebei China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Hebei China School of Traffic and Transportation Shijiazhuang Tiedao University Hebei China

In order to study the damage and failure of asphalt mixture under uniaxial loading under freeze-thaw cycle, a damage constitutive model is constructed based on the Particle Flow Code (PFC2D). Through four sets of uniaxial compression laboratory tests with different freeze-thaw cycles, numerical simulation with the help of PFC2D, analysis of macroscopic failure of asphalt mixture and evolution law of internal microcracks from mesoscopic perspective, the equation of the relationship between the damage variable and the strain is established. The results of the study showed that: (1) The numerical simulations are in good agreement with the experimental results. (2) The increase of freeze-thaw cycles will increase the freeze-thaw damage variable and peak strain of asphalt mixture and reduce the compressive strength of asphalt mixture. (3) The established piecewise function expression can fit the relationship between the damage variable and the strain well. This study provides a convenient method for the mesoscopic study of asphalt mixture loading test under freeze-thaw cycle. © 2023, The Authors. All rights reserved.

关键词： Asphalt mixtures

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Study on dynamic slaking response characteristics and calculation model of fouled ballast materials in heavy-haul railways

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Construction and Building Materials 2025年 481卷

作者： Yang, Zhihao Liu, Hengwen Deng, Xi Feng, Huaiping Chang, Jianmei Ma, Deliang Feng, Xiaoqing State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China School of Traffic and Transportation Shijiazhuang Tiedao University Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China

Investigating the dynamic slaking characteristics of fouled ballast is critical for elucidating the mud pumping mechanisms in heavy-haul railway ballasted track beds. In this study, in-situ fouled ballast materials from typical mud pumping sections were collected, and a series of dynamic slaking triaxial tests were conducted. The coupled effects of loading frequency, dynamic stress amplitude, and confining pressure on deformation behavior, water infiltration patterns, and moisture migration characteristics under dynamic slaking conditions were systematically examined. Moreover, the evolutionary mechanisms of softening indices in plastically creeping specimens were quantitatively analyzed, yielding computational models for both softening indices and accumulative plastic strain. Furthermore, based on the improved Iwan series model, a calculation model of the dynamic stress-strain relationship considering the load amplitude and frequency under dynamic slaking conditions was established. The dynamic slaking deformation mechanism of fouled ballast was discussed from three aspects: the hysteresis effect of dynamic slaking deformation, the critical frequency regulation mechanism, and the hydromechanical coupling and feedback laws. Based on the findings, a "frequency-amplitude" collaborative control strategy is proposed for mitigating mud pumping diseases in ballasted track beds. © 2025 Elsevier Ltd

关键词： Ballast (railroad track)

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Synthesis and Performance Characterization of a Low Adsorption Clay-resistant Polycarboxylate Superplasticizer

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Journal of Wuhan University of Technology(Materials Science) 2021年第3期36卷 446-455页

作者： ZHANG Ying WANG Pengshuo SUN Guowen YANG Jianming GAO Rui School of Materials Science and Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China College of Civil Engineer-ing Yancheng Institute of TechnologyYancheng 224051China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang050043China Heibei Key Laboratory of Advanced Materials for Transportation Engineering and Environment Shijiazhuang Tiedao UniversityShijiazhuang050043China

A low adsorption clay-resistant polycarboxylate superplasticizer(KN-PC)was synthesized using acrylic acid and isopentenol polyoxyethylene ether as the main reaction *** structural characterization and clay-resistant mechanism of the KN-PC were explored using Fourier transform infrared spectroscopy and X-ray diffraction,and the effect of the KN-PC on the performance of composite paste with various montmorillonite(MMT)contents was *** with ordinary polycarboxylate superplasticizer(PC),the KN-PC has a low sensitivity to the *** the action of the MMT,the adsorption dosage of the KN-PC on the MMT is much smaller than that of the PC.

关键词： polycarboxylate superplasticizer clay-resistant montmorillonite performance synthesis

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A sequoia-ecology-based metaheuristic optimisation algorithm for multi-constraint engineering design and UAV path planning

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Results in engineering 2025年 26卷

作者： Fan, Shijie Wang, Ruichen Su, Kang Song, Yang Wang, Rui State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China School of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China School of Electrical Engineering Southwest Jiaotong University Chengdu611756 China

Current metaheuristic algorithms are typically confined to inspiration from singular perspectives, isolated biological behaviours, or individual phenomena, resulting in inherent limitations that have motivated this study. Diverging from conventional approaches, this paper explores complex biological systems from an ecosystem perspective and conducts comprehensive system modelling, analysis, and algorithmic innovation. Specifically, a novel metaheuristic optimization algorithm inspired by the self-regulating and restorative phenomena observed in sequoia forest ecosystems called the Sequoia Optimization Algorithm (SequoiaOA) is proposed. The sequoia ecosystem exhibits distinctive characteristics including collective growth, resource sharing and networking, adaptability and resilience, reproduction and diversity, and elite retention. Building upon these phenomena, this work presents the first formulation of SequoiaOA, developing its mathematical model and engineering applications through algorithmic modelling and validation from the perspective of ecosystem complexity, self-regulation, and resilience in macro systems. Comparative experiments employing CEC2017 and CEC2022 benchmark functions demonstrate the algorithm's effectiveness through benchmarking against six established metaheuristic algorithms. SequoiaOA achieved superior performance in over 40 % of test functions, outperforming competitors in terms of mean values and variance of objective function measures. Furthermore, its efficacy in addressing real-world multi-constrained engineering challenges was validated through eight engineering design problems. Additional modelling and application experiments in UAV path planning underscore its practical applicability to trajectory optimization tasks. The in-depth discussions reveal that SequoiaOA possesses significant potential for future enhancements and demonstrates broad suitability for diverse optimization problems. The implementation code is available in the Appe

关键词： Biotic

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Fault Diagnosis Method for Multiple Sources based on IESFSC-SSRgram

Fault Diagnosis Method for Multiple Sources based on IESFSC-...

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International Conference on Sensing, Diagnostics, Prognostics, and Control (SDPC)

作者： Wu Zhihao Gong Shixian Huang Chenguang Jin Hang Liu Zechao National Engineering Laboratory CRRC Qingdao Sifang Locomotive and Rolling Stock Co. Ltd Qingdao China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structure and School of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang China Weichai Power Co. Ltd. Data Management Engineering Center Weifang China Institute of Magnetic Levitation and Electromagnetic Propulsion China Aerospace Science and Industry Corporation Limited Beijing China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang China

ISBN: (数字)9798350388855

ISBN: (纸本)9798350388862

The division and determination of frequency bands are always core problems in fault diagnosis methods for rotating machinery. Currently, the frequency band division strategy of most fault diagnosis methods is the 1/3-binary tree or realized by wavelet packet transform (such as fast kurtosis diagram and Autogram). This method is relatively fixed, making it difficult to accurately cover the resonance frequency band and achieve multi-source fault identification. To address the above problems, an adaptive frequency band division strategy based on Fast Spectral Correlation (FSC) and Scale-Space Representation (SSR) is proposed. The enhanced enveloping spectrum (EES) of each frequency band after division is obtained, and the improved Fault Quantification Index (IFQI) is used to measure the richness of target information in each enveloped spectrum (ES), generating a two-dimensional diagram. The envelope spectrum with the largest IFQI value is selected as the improved envelope spectrum (IES) obtained by the FSC and SSR division strategy (IESFSC-SSRgram), enabling the fault diagnosis of the axle box bearing. The effectiveness and superiority of the proposed method in identifying multi-source concurrent faults in the wheelset bearing system are verified by comparing it with the traditional method.

关键词： Fault diagnosis Correlation Resonant frequency Frequency conversion Wavelet packets Power capacitors Frequency measurement Sensors Indexes Frequency control

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Response Characteristics of a Piezoelectric Semiconductor Layer Under a Rigid Spherical Indenter

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SSRN 2024年

作者： Liu, Jinxi Gao, Shijing Ju, Chengjian Nie, Guoquan Chen, Weiqiu State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China School of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China Department of Engineering Mechanics Hebei Key Laboratory for Mechanics of Intelligent Materials and Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Key Lab of CAD & CG Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Department of Engineering Mechanics Zhejiang University Hangzhou310027 China

This paper considers the axisymmetric frictionless indentation responses of a piezoelectric semiconductor (PSC) layer, which is perfectly bonded to a rigid substrate and acted on by a rigid spherical indenter. While both the indenter and the rigid substrate are assumed to be electrically insulating, the interaction of piezoelectricity and semiconducting property of PSC is fully taken into consideration. By the Hankel integral transformation, the indentation problem is reduced to a Fredholm integral equation of the second kind, which is solved numerically. The variations of the indentation force, electric potential and contact radius with the indentation depth are obtained. The effects of the layer thickness, indenter size and semiconducting on the variation relationships are analyzed in detail to achieve a better understanding of the response of the PSC layer under indentation. Furthermore, the theoretical results based on the singular integral equation method are verified by the finite element simulation. © 2024, The Authors. All rights reserved.

关键词： Piezoelectricity

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Mitigation of Shady-Sunny Slopes Effect on Subgrade by Photovoltaic Sheltered Boards in Permafrost Regions

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SSRN 2024年

作者： Tian, Run-Ze Li, Xiao-Kang Zhang, Yu Zhang, Lu-Xin Yue, Zu-Run Li, Xu Key Laboratory of Urban Underground Engineering of Ministry of Education Beijing Jiaotong University Beijing China School of Traffic and Transportation Lanzhou Jiaotong University Lanzhou730070 China China Railway Northwest Science Research Institute Co. Ltd China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang China

The temperature disparity between shady and sunny slopes leads to uneven subgrade deformation in permafrost regions. In response, this paper introduces a novel photovoltaic sheltered boards (PSB) subgrade and conducts a numerical investigation into its mitigation of shady-sunny slopes effect. The study commences with developing a two-dimensional heat transfer model, accounting for the coupled boundary of solar radiation and air convection. The numerical model was validated through monitored temperature data from the Beiluhe observation station. Subsequently, the study calculates the temperature distribution of the exposed subgrade to illustrate the effect of shady-sunny slopes and identify influencing ***, this study explores the feasibility of equalizing differential temperatures through insulated boards (IB), which refers to the traditional subgrade with laid IB and the novel PSB subgrade with suspended IB. Finally, the mitigation effects of temperature difference of two modes are compared, considering key parameters including solar radiation, subgrade alignment, wind speeds, and reflection rate. The study concludes that solar radiation significantly influences the shady-sunny slope effect, followed by subgrade direction, wind speed, and reflection rate. Both IB and PSB modes can reduce thaw depths and mitigate the shady-sunny slope effect by blocking solar radiation, with PSB demonstrating superior effects due to heat convection among an adjustable suspension height. Additionally, PSB results in a reduction of over 3 ℃ in the average annual temperature of the sunny slope and is recommended to be suspended at a height exceeding 5.3 cm in the research area. In summary, the PSB subgrade effectively mitigates shady-sunny slopes and is recommended with comprehensive consideration of mitigation performance and carbon emissions. © 2024, The Authors. All rights reserved.

关键词： Heat convection

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Research on the Control Technology of High Water Temperature Tunnel Grouting Water Plugging and Heat Insulation 11th

Research on the Control Technology of High Water Temperature...

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11th International Conference on Civil engineering, ICCE 2024

作者： Yang, Tengjie Tian, Baolei Xue, Yongqing Gao, Xinqiang State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China China Railway 18th Bureau Group Corporation Limited Tianjin300222 China

ISBN: (纸本)9783031879586

The surrounding rock experiences the combined impacts of elevated ground stress, high water pressure, and hot groundwater during the deep-buried tunnels with high water temperatures. The stress in the surrounding rock and groundwater flow significantly affects the temperature variations in the tunnel's construction environment. Therefore, studying heat insulation and cooling measures while constructing high-water temperature tunnels is significant. This study uses a numerical simulation method to analyze water plugging and cooling feasibility in high-water temperature tunnels through grouting measures under thermal-fluid-solid coupling conditions. The variation characteristics and laws of the tunnel's stress field, seepage field, and temperature field surrounding rock under different grouting parameters are discussed. The results show that underground hot water is significantly lost when tunnels are excavated without grouting, and the tunnel wall's cooling effect is inferior. After constructing a 5 m grouting ring, excavating the tunnel significantly affects the seepage and temperature fields within the grouting ring. The seepage flow of underground hot water in the tunnel is reduced to about 1/2942 of its original value before grouting, and the temperature of the tunnel wall is significantly reduced. Through orthogonal testing, the order of influence of different grouting parameters on the average temperature of the tunnel wall is determined as follows: grouting permeability k > grouting thickness d > solid thermal conductivity of the grouting ring λ > thermal expansion coefficient of the grouting ring β. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Thermal insulation

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Wind tunnel tests on aerodynamic characteristics of vehicles on same-storey highway and rail bridge under crosswind

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Journal of Central South University 2022年第8期29卷 2513-2531页

作者： ZOU Yun-feng XUE Fan-rong HE Xu-hui HAN Yan LIU Qing-kuan School of Civil Engineering Central South UniversityChangsha 410075China Hunan Provincial Key Laboratory for Disaster Prevention and Mitigation of Rail Transit Engineering Structure Changsha 410075China School of Civil Engineering and Architecture Changsha University of Science&TechnologyChangsha 410004China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China

In recent years,the safety and comfort of road vehicles driving on bridges under crosswinds have attracted more attention due to frequent occurrences of wind-induced *** study focuses on a container truck and CRH2 high-speed train as research *** tunnel experiments are performed to investigate shielding effects of trains on aerodynamic characteristics of *** results show that aerodynamic interference between trains and trucks varies with positions of trains(upstream,downstream)and trucks(upwind,downwind)and numbers of *** summarize,whether the train is upstream or downstream of tracks has basically no effect on aerodynamic forces,other than moments,of a truck driving on windward sides of bridges(upwind).In contrast,the presence of trains on the bridge deck has a significant impact on aerodynamic characteristics of a truck driving on leeward sides(downwind)at the same *** best shielding effect on lateral forces of trucks occurs when the train is located downstream of ***,the pressure measuring system shows that only lift forces on trains are affected by trucks,while other forces and moments are primarily affected by adjacent trains.

关键词： same-storey highway and rail bridge container truck CRH2 high-speed train aerodynamic characteristics wind tunnel test crosswind

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A Numerical Study of the Aerodynamic Effect of the Ski-Suits Surface Roughness on the Ski Jumping Athlete During the Flight Phase

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SSRN 2023年

作者： Liu, Kan Wang, Zeyuan Liu, Qingkuan State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University China School of Civil Engineering Shijiazhuang Tiedao University China Innovation Center for Wind Engineering and Wind Energy Technology of Hebei Province China

Surface roughness of the ski-suits can have significant effect on the aerodynamic performance of the ski jumping athlete. Herein, several typical surface roughness configurations are examined through numerical simulations. The three-dimensional athlete model is subjected to both uniformly distributed and non-uniformly distributed surface roughness. Furthermore, the athlete's model is segmented into distinct body parts to conduct a comprehensive analysis of the aerodynamic contributions from each individual segment. It is observed that the that the trunk of the athlete and the skis play predominant roles in generating aerodynamic forces during the flight phase. Additionally, the optimal surface roughness values for each part of the ski-suits are determined using a uniformly distributed model. Subsequently, these distinct optimal roughness values are combined to create a mixed, non-uniformly distributed surface roughness model, to achieve an overall optimal design of the ski-suits. Flow structures are also presented to analyse the impact of these various surface roughness conditions. It is noted that the flow suppression near the back region of the athlete body can significantly reduce the resistance force in the horizontal direction. © 2023, The Authors. All rights reserved.

关键词： Surface roughness

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