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Cause Analysis of Rail Abnormal Corrugation on the Cologne Egg Fastener Track in Metro Straight Section

Zhendong Ceshi Yu Zhenduan/Journal of Vibration, Measurement and Diagnosis 2025年第2期45卷 240-247and408页

作者： Wang, Zhiqiang Lei, Zhenyu Tong, Fengzhuang State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety Shanghai201804 China

In order to study the rail abnormal corrugation on the Cologne egg fastener track in the metro straight section, a two-dimensional numerical model reflecting the energy dissipation characteristics of the wheel-rail system is proposed. Combined with field investigation and numerical calculation, the cause characteristics of rail corrugation are analyzed. The results show that with the increase of the proportion of longitudinal creep force, when the excitation is applied above the fastener, the longitudinal creep force has a greater effect on the occurrence probability and development trend of rail corrugation;when the excitation is applied in the middle of the fastener span, both the longitudinal and transverse creep force can promote the generation and development of rail corrugation in this case. In the process of increasing the proportion of longitudinal creep force, the sensitivity to the real part of the system dissipation energy gradually changes from wavelength sensitivity to velocity sensitivity;meantime, the wavelength remains constant at different speeds or shows a nonlinear relationship with the speed, indicating that sensitive speeds of corrugation wavelengths are different under different creep force conditions. The influence analysis of rail receptances shows that under different creep force conditions, the same characteristic frequency appears and is close to the passing frequency of measured corrugation, illustrating that the rail vertical receptance characteristic when the excitation is applied above the fastener is the main cause of the rail corrugation. © 2025 Nanjing University of Aeronautics an Astronautics. All rights reserved.

关键词： keyways

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NUMERICAL STUDY ON TRANISENT NATURAL CONVECTION IN COAL SHED ENCLOSED OF SINGLE COAL PILE

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Gongcheng Lixue/engineering Mechanics 2023年第10期40卷 237-246页

作者： Wang, Wen-Yue Cui, Hui-Min Han, Zhi-Ming Liu, Qing-Kuan Department of Mathematics and Physics Shijiazhuang Tiedao University Hebei Shijiazhuang050043 China State Key Laboratory of Mechanical Behavior System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Hebei Shijiazhuang050043 China Innovation Center for Wind Engineering Wind Energy Technology of Hebei Province Hebei Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Hebei Shijiazhuang050043 China

In recent years, the environmentally friendly closed coal shed has been widely used in actual production and life. The heat released from the coal pile will cause local overheating of the environment, which will affect the comfort and health of workers. So the problem of convective heat transfer in coal shed has attracted extensive attention. In order to reduce the harm of coal heap heat release, it is necessary to understand the mechanism of heat transfer and flow in the process of coal heap heat release. CFD numerical simulation method is used to study the natural convection phenomenon in the closed large span coal shed with a single coal pile. Under unsteady conditions, the heat transfer characteristics and flow transition around coal pile with fixed Rayleigh number are studied. The emergence time of symmetric and asymmetric flow structures in coal shed under different Rayleigh numbers are studied. The unsteady characteristics of flow in full development stage are given. The results show that the transient flow in the coal shed will go through three different stages: initial stage, transitional stage and quasi-steady stage. During the transitional stage, the separation and shedding of the plume will promote the formation of asymmetric structure in coal shed, and the emergence time of asymmetric phenomenon will advance with the increase of Rayleigh number. In the quasi-steady stage, the flow in the coal shed presents the characteristics of irregular unsteady turbulent flow, and the time to reach full-development state is delayed with the increase of Rayleigh number. © 2023 Tsinghua University. All rights reserved.

关键词： Coal

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Curing Stress Effect on Stability, Microstructure, Matric Suction and Electrical Conductivity of Cementitious Tailings Backfills

SSRN

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SSRN 2022年

作者： Chen, Shunman Yilmaz, Erol Wang, Wei Wang, Yi-Ming School of Civil Engineering and Architecture East China Jiaotong University Jiangxi Nanchang330013 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Hebei Province Shijiazhuang050043 China Jiangxi Key Laboratory of Disaster Prevention-mitigation and Emergency Management East China Jiaotong University Jiangxi Nanchang330013 China Department of Civil Engineering Geotechnical Division Recep Tayyip Erdogan University Fener RizeTR53100 Turkey School of Civil and Resources Engineering University of Science and Technology Beijing Beijing100083 China

Cementitious tailings backfill (CTB) is a regularly used technique for most mines at home and aboard since it has a significant meaning for the recycling of total tailings and enhances the safety of underground mines. Thus, studying the behavior of the CTB materials exposed to diverse curing stresses is fairly vital to guarantee the whole stability and long-term ageing of underground mining structures. This paper inspects the effect of diverse curing stresses (0 kPa – witness, 180 kPa, 360 kPa and 540 kPa) on physico-mechanical characteristics of CTB materials subjected to a curing age of up to 28 days. Based on lab tests, uniaxial compression and microstructure analyses are performed for all the specimens. To well characterize the self-desiccation behavior of CTB specimens, suction and electrical conductivity are also scrutinized during their curing processes. Results indicate that curing of CTBs under stress ranging from 0 to 540 kPa can improve their strength gains to some extent. Irrespective of curing stress, CTB’s suction is enlarged while its porosity is dropped once increased with curing age and stress, respectively. There exists a robust power function between suction and strength while there is a linear link between electrical conductivity and strength. One can state from this study that curing stress must be significantly taken into account during the backfill mixture proportions’ design. © 2022, The Authors. All rights reserved.

关键词： Pore structure

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An Improved Autogram and its Application in Bearing Fault Diagnosis

An Improved Autogram and its Application in Bearing Fault Di...

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Prognostics and system Health Management (PHM-Jinan), International Conference on

作者： Wenpeng Liu Shaopu Yang Qiang Li Yongqiang Liu School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang China

ISBN: (数字)9781728151816

ISBN: (纸本)9781728151823

Envelope analysis is one of the most advantageous methods in rolling element bearing (REB) diagnosis, but the determination of the informative frequency band (IFB) is always a huge challenge. In order to reduce the influence of discrete frequency components and strong background noise to choose IFB, a new improved Autogram is provided. Firstly, the Cepstrum pre-whitening (CPW) is taken as a preprocessing method to reduce the interference from discrete frequency components in the signal. Then, the Autogram is used to decompose the pre-whitening signal and the optimal IFB is selected for a further demodulation. The simulated signals and a set of experiment signals are taken to verify its validity. The results indicates that this method can successfully address the interference generated by discrete frequency and strong background noise, and effectively extract the weak fault features of bearing.

关键词： Interference Time-frequency analysis Coplanar waveguides Noise measurement Vibrations Cepstrum Gears

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Data-Driven Turbulence Model for Unsteady Cavitating Flow

SSRN

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SSRN 2022年

作者： Zhang, Zhen Wang, Jingzhu Huang, Renfang Qiu, Ruidi Ye, Shuran Wang, Yiwei Liu, Qingkuan State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Innovation Center for Wind Engineering and Wind Energy Technology of Hebei Province Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of Mechanics Chinese Academy of Sciences Beijing100190 China School of Future Technology University of Chinese Academy of Sciences Beijing100049 China School of Engineering Science University of Chinese Academy of Sciences Beijing100049 China

Reynolds-averaged Navier-Stokes (RANS) equations have been widely used in engineering fields to investigate cavitating flow owing to their low computational cost and excellent robustness. However, it is challenging to accurately obtain the unsteady characteristics of cavitating flow owing to cavitation-induced phase transitions. In this study, we propose an implicit data-driven RANS (DD-RANS) framework based on a higher-order eddy viscosity model to analyze the unsteady characteristics of cavitating flow. In the DD-RANS framework, a basic computational model is developed by introducing a cavitation-induced phase transition into the equations of Reynolds stress in the process of turbulence modeling. To improve the computational accuracy and generalization performance of the basic model, the linear and nonlinear parts of the anisotropic Reynolds stress tensor are predicted through implicit and explicit methods, respectively. A data fusion approach, allowing the input and output of characterized parameters at multiple time points, is presented to obtain the unsteady characteristics of the model dataset. The neural networks in the DD-RANS model are trained using the numerical results obtained via large eddy simulation (LES). The training data consists of two parts: (i) the results obtained at cavitation numbers of 2.0, 2.2, and 2.7 for a Venturi flow, and (ii) those obtained at cavitation numbers of 0.8 and 1.5 for a NACA66 hydrofoil. The DD-RANS model is used to predict the cavitating flow at cavitation numbers of 2.5 for a Venturi flow and 0.8 for a Clark-Y hydrofoil. It is found that the DD-RANS model is superior to the baseline RANS model in predicting the instantaneous periodic shedding of a cavity and the mean flow fields. Furthermore, the developed DD-RANS exhibited excellent generalization abilities. © 2022, The Authors. All rights reserved.

关键词： Cavitation

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Effects and mechanisms of the main longitudinal beam shape on vortex-induced vibrations of Π-shaped composite girders

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structures 2025年 78卷

作者： Kaiwen Li Yifei Sun Qingkuan Liu Yangxue Wang Qingcai Wang Binxuan Wang School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang 050043 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang 050043 China Key Laboratory of Roads and Railway Engineering Safety Control Ministry of Education Shijiazhuang 050043 China Innovation Center for Wind Engineering and Wind Energy Technology of Hebei Province Shijiazhuang 050043 China Research Center for Wind Engineering and Engineering Vibration Guangzhou University Guangzhou 510006 China

As a typical blunt body cross-section, Π-shaped composite girders are notably susceptible to vortex-induced vibrations (VIVs). Therefore, it is crucial to investigate their VIV characteristics and develop corresponding aerodynamic countermeasures. In the present study, synchronous pressure and vibration measurements, combined with computational fluid dynamics (CFD) simulations, were conducted for various Π-shaped composite girder models with different main longitudinal beam shapes. The effects of the main longitudinal beam height ( h ), bottom plate width ( b ), and bottom plate inclination angle ( β ) on the vertical VIV were systematically investigated. The underlying mechanisms of VIV for these parameters were discussed by analyzing the time-frequency characteristics of aerodynamic forces, the relationship between local lift forces and vortex-excited forces (VEFs), and flow field characteristics. The results indicate that reducing h , increasing b , or setting β to 20° can suppress vertical VIV, but the suppressive effect varies and is related to the wind attack angle. From the perspective of the flow field, the formation and movement of the large separation vortices at the leading edge of the girder are responsible for the observed vertical VIVs. The aforementioned parameter adjustments that exhibit an excellent VIV suppression effect can reduce the size and suppress the development of the leading-edge vortices, thereby improving the stability of the flow field. From the perspective of aerodynamic force characteristics, these adjustments can reduce the RMS value of the surface pressure coefficient. They can also shift the dominant frequency of the pressure spectrum away from the vibration frequency, weaken the dominant role of the vibration frequency in the overall lift, and greatly reduce the contribution of local lift to the overall vortex-excited forces (VEFs). As a result, VIV is suppressed.

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Parametric Influences of Stability and Settlement Pattern of Embankment on Slope Foundation 4

Parametric Influences of Stability and Settlement Pattern of...

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2020 4th International Conference on Water Conservancy, Hydropower and Building engineering, WCHBE 2020

作者： Zhang, Ouyang Yang, Guangqing Zhao, Yunfei Lu, Huali Hou, Licheng Third Construction Engineering Company Ltd. China Construction Second Engineering Bureau Ltd. Beijing100070 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang050043 China School of Traffic and Transportation Shijiazhuang Tiedao University Shijiazhuang050043 China China State Construction Engineering Corp. Ltd Beijing100020 China

Building a subgrade on the slope foundation is common for highway constructions in China. Under different hydrogeological conditions, the stability and differential settlement are the main problems for the construction of the subgrade. In order to study the parameters that influence the stability and deformation of subgrade, based on the cross-section of a mountainous region highway, those simulations were conducted to study the influence of subgrade height, subgrade width, embankment slope angle, and slope foundation angle on the stability and pattern of embankment. The results showed that the allowable filling height is 15 m;otherwise, there is a large risk of the slope sliding. Further, it was found that the maximum vertical deformation on the right shoulder of the embankment increases with an increase in the angles of the slope of the foundation. These results provide references for future highway constructions and design works in mountainous areas. © Published under licence by IOP Publishing Ltd.

关键词： Deformation

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Research on Multi-Scale High-Fidelity Digital Model and Reduced-Order Model for Digital Twin Modeling of Composite structures

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Forest Chemicals Review 2021年第JULY-AUGUST期2021卷 1469-1482页

作者： Zuo, Jiale Li, Dong Zhou, Ling Zhang, Cun Wang, Huicong Nanchang Hangkong University School of Aircraft Engineering Jiangxi Nanchang330063 China Hebei Jiaotong Vocational and Technical College Center for Quality Management Hebei Shijiazhuang050035 China Shijiazhuang Tiedao University State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Hebei Shijiazhuang050043 China Hebei Jiaotong Vocational and Technical College Department of Road and Bridge Engineering Hebei Shijiazhuang050091 China

The research purpose of this paper is to establish a multi-scale high-fidelity digital model and a reduced-order model for digital twin of composite structures. Firstly, a high-fidelity digital model is established for the composite structure using micro-meso-macro multi-scale method to accurately describe the composite structure. Then, in order to meet the real-time needs of digital twin, the reduced-order model is studied by using three training algorithms for comparative study: Bayesian Regularization (B-R), Levenberg-Marquardt (L-M), and Scaled Conjugate Gradient (SCG). B-R training algorithm with smaller error is chosen to establish a neural network reduced-order model. Finally, with the multi-scale high-fidelity digital model as a reference, the maximum error of the established reduced-order model is 5.64%, which can meet the needs for multi-scale digital twin modeling of composite structures. © 2021 Kriedt Enterprises Ltd. All right reserved.

关键词： Structure (composition)

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A decarbonization strategy for lattice girders in primary support: A case study in Wanrong tunnel on Meng-Hua railway

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Case Studies in Construction Materials 2025年 22卷

作者： Feng Lu Zhenyu Chen Xianshun Zhou Yingda Zhang Wenge Qiu Xinqiang Gao Kai Liu School of Emergency Management Xihua University Chengdu Sichuan 610039 China Key Laboratory of Transportation Tunnel Engineering Ministry of Education School of Civil Engineering Southwest Jiaotong University Chengdu Sichuan 610031 China School of Civil Engineering and Transportation Engineering Shenzhen University Shenzhen Guangdong 518060 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang Hebei 050043 China Department of Civil and Environmental Engineering Louisiana State University Baton Rouge LA USA

China faces an urgent need to reduce carbon emissions, and tunnel construction will play a critical role in achieving this goal. While much focus has been placed on new construction materials, the potential carbon emission reductions from structural optimization have been largely overlooked. This study addresses the issue of overdesign in tunnel lattice girders (LG) and achieves two key outcomes: preventing overdesign while ensuring tunnel safety, and demonstrating the decarbonization potential and economic benefits of optimizing the LG structure. The LG overdesign was found to stem from an overestimation of loose soil load in Chinese regulations. After accounting for the resistance of surrounding rock, mechanical evaluations revealed that the main steel bars near the rock side, diagonal bars, welds, and stirrups contribute minimally to the load-bearing capacity of the LG. An optimization strategy was proposed, involving adjustments to the diameters of the main steel and diagonal bars, the reduction of weld lengths, and the elimination of stirrups. On-site experiments conducted in the Wanrong tunnel of the Meng-Hua railway confirmed the safety of the optimized design and demonstrated a 36.77 % reduction in carbon emissions, amounting to 3462.85 tons, with a decrease of 0.4849 t/m in carbon emission intensity compared to standard designs. Further emission analysis considered quantities, contributing factors, construction stages, and individual components. Compared to the traditional scheme, the optimized solution has reduced the total project cost by 36.76 %. The decarbonization strategy proposed in this study provides a possible solution for future tunnel constructions.

关键词： Carbon emission Lattice girders Sustainable tunnel construction mechanical performance

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An enhanced bond-breaking model incorporated in smoothed particle hydrodynamics for simulating the failure process

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engineering Analysis with Boundary Elements 2025年 179卷

作者： Jianqiang Wang Ting Long School of Mechanical Engineering Guangxi University Nanning 530004 China State Key laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Guangxi University Nanning 530004 China Guangxi Key lab of Manufacturing System and Advanced Manufacturing Technology Guangxi University Nanning 530004 China

The initiation and propagation of cracks involve the abrupt transition of materials from continuous media to discrete separation, posing significant challenges to numerical simulations. In this paper, an enhanced bond-breaking model base on the pseudo-spring model is developed to model the failure process of rock-like materials. The new model maintains the integrity of the particle support domain and avoids unphysical phenomena during bond breakage. And this study achieved the prefabrication of initial cracks by artificially controlling bond breakage. In addition, the artificial stress and viscosity and kernel gradient correction are applied to improve the computational accuracy and stability. Several examples are investigated to verify the efficiency of the present SPH method with the enhanced damage model, comparing with experimental results, the present SPH method accurately captures the material's actual damage behavior, providing a valuable reference for rock material failure analysis.

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