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Establishment of Dynamic Model of axle Box Bearing of high-speed Train under Variable Speed Conditions

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Research Square

Research Square 2021年

作者： Liu, Yongqiang Wang, Baosen Zhang, Bin Yang, Shaopu School of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China School of Traffic and Transportation Shijiazhuang Tiedao University Shijiazhuang050043 China College of engineering and computing University of South Carolina ColumbiaSC29208 United States State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China

This paper establishes a dynamic model of the bearing rotor system of a high-speed train under variable speed conditions. Different from previous works, the proposed model simplifies the contact stress and considers the compensation balance excitation caused by the rotor mass eccentricity. The angle iteration method is used to solve the challenging problem that the roller space position cannot be determined in bearing rotation. The simulation results show that the model accurately describes the dynamics of bearing under varying speed profiles that contain acceleration, deceleration and speed oscillation stages. The order ratio spectrum of the bearing vibration signal indicates that both single frequency and multiple frequency in simulation results are consistent with that in theoretical results. Experiments of bearing with outer ring fault and inner ring fault under various operating conditions are presented to verify the developed model. © 2021, CC BY.

关键词： Dynamic models

Ride Comfort and Energy Harvesting of Inflatable Hydraulic-Electric Regenerative Suspension system for Heavy-Duty Vehicles

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SSRN 2023年

作者： Zhang, Buyun Luo, Minglu Li, Shaohua Tan, Chin-An Liu, Zhiqiang Automotive Engineering Research Institution Jiangsu University Jiangsu Zhenjiang212013 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Hebei Shijiazhuang050043 China Department of Mechanical Engineering Wayne State University DetroitMI48202 United States School of Automotive and Traffic Engineering Jiangsu University Jiangsu Zhenjiang212013 China

Heavy-duty vehicles (HDVs) experience severe vibrational environments when traveling on rough roads and dissipate considerable energy in the suspension system because of the dampers working, and the intense vibrations induced by the road roughness are transmitted to the vehicle body and the cockpit, greatly affecting the driver's ride comfort. Therefore, an inflatable hydraulic-electric regenerative suspension (IHERS), which can mitigate the vehicle’s vibration and recover some energy dissipated by the damper, was proposed in this study. The configuration and working principle of the IHERS was then interpreted and the corresponding mathematical model was established based on the hydraulic system's pressure drop and flow relationship. A half-car model with 5-degree-of-freedom including the cockpit was developed to assess the performance of the IHERS-equipped HDVs. Structural and non-structural parametric study of the influences on the IHERS was conducted in depth to better understand the damping forces. Simulation examples were taken to investigate the performance of energy recovery and dynamic behaviors of this type of vehicle, comparing to those of a vehicle with a traditional passive suspension. The results indicate that the equivalent damping coefficients range of IHERS fits within the HDVs’ damping force range. Moreover, the damping force can be adjusted by tuning the external resistance of IHERS, which can be used for control of semi-active suspension. The energy conversion efficiency increases up to 41.9% when the IHERS-equipped HDV travels on the class-C road at 20 m/s. The design of IHERS can improve the ride comfort, reducing vertical acceleration of the cockpit by 23.3% comparing to a traditional suspension, of an HDV. © 2023, The Authors. All rights reserved.

关键词： Energy harvesting

Illumination robust loop closure detection with the constraint of pose

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arXiv

arXiv 2019年

作者： Deli, Yan Wenkun, Tuo Weiming, Wang Shaohua, Li State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China School of Electrical and Electronic Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China School of Electronic and Information Engineering Beijing Jiaotong University Beijing100044 China

Background: Loop closure detection is a crucial part in robot navigation and simultaneous location and mapping (SLAM). Appearance-based loop closure detection still faces many challenges, such as illumination changes, perceptual aliasing and increasing computational complexity. Method: In this paper, we proposed a visual loop-closure detection algorithm which combines illumination robust descriptor DIRD and odometry information. The estimated pose and variance are calculated by the visual inertial odometry (VIO), then the loop closure candidate areas are found based on the distance between images. We use a new distance combing the the Euclidean distance and the Mahalanobis distance and a dynamic threshold to select the loop closure candidate areas. Finally, in loop-closure candidate areas, we do image retrieval with DIRD which is an illumination robust descriptor. Results: The proposed algorithm is evaluated on KITTI_00 and EuRoc datasets. The results show that the loop closure areas could be correctly detected and the time consumption is effectively reduced. We compare it with SeqSLAM algorithm, the proposed algorithm gets better performance on PR-curve. Copyright © 2019, The Authors. All rights reserved.

关键词： Mapping

Investigation on the reinforcement effect of a bedding slope affected by a landsliding block

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Arabian Journal of Geosciences 2022年第6期15卷 1-20页

作者： Zhang, Fei Yang, Tianhong Li, Lianchong Zhu, Xinping Key Laboratory of Roads and Railway Engineering Safety Control Shijiazhuang Tiedao University Ministry of Education Shijiazhuang China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang China Center of Rock Instability and Seismicity Research School of Resources and Civil Engineering Northeastern University Shenyang Liaoning China China Coal Technology and Engineering Group Shenyang Research Institute Fushun China

The south slope of Fushun west open-pit mine located in Northeast China is a high-deep rock slope. In the last few years, a landsliding block has gradually formed in the south slope. Owing to the effect of sliding force caused by the sliding block, some damage has occurred on the foundation of Kengkou refinery which constructed in the west of the south slope. To improve the stability of the refinery foundation, three group micro-pile structures were employed to cut off the drag of the sliding block and reinforce the refinery on the southwest slope. In this study, a comprehensive method combining the microseismic monitoring technique and numerical simulation method was used, the stability of the southwest slope was evaluated, and reinforcement mechanism was deeply analyzed. A microseismic monitoring system is established on-site to obtain useful information about the damage energy, location, and magnitude of the rocks in the southwest slope. Thus, the west boundary of the landslide in the south slope of the open-pit is determined. By analyzing the numerical results, the stress concentration is discovered mainly around the micro-pile structures and near the west boundary. After reinforcement, the displacement decrease in the south-north direction is apparent. To investigate the interaction mechanism between the micro-pile and the surrounding rock mass, a local 3D numerical model is employed to help understand auxiliary information about the stress state and stress redistribution induced by failure in the surrounding rock mass. It is shown that the reinforcement effect becomes more and more evident with the increase in the number of employed micro-piles. The numerical results and in situ GPS displacement monitoring data illustrate that the micro-pile structures have an excellent strengthening result in controlling the deformation of the slope. The comprehensive methodology provides an effective way to estimate the stability and the reinforcement effect of the slope und

关键词：

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

Invariant cubature kalman filter for monocular visual inertial odometry with line features

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arXiv

arXiv 2019年

作者： Deli, Y.A.N. Chunhui, W.U. Wang, Weiming Song, Yu Li, Shaohua State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China School of Electrical and Electronic Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China School of Electronic and Information Engineering Beijing Jiaotong University Beijing100044 China

To achieve robust and accurate state estimation for robot navigation, we propose a novel Visual Inertial Odometry(VIO) algorithm with line features upon the theory of invariant Kalman filtering and Cubature Kalman Filter (CKF). In contrast with conventional CKF, the state of the filter is constructed by a high dimensional Matrix Lie group and the uncertainty is represented using Lie algebra. To improve the robustness of system in challenging scenes, e.g. low-texture or illumination changing environments, line features are brought into the state variable. In the proposed algorithm, exponential mapping of Lie algebra is used to construct the cubature points and the re-projection errors of lines are built as observation function for updating the state. This method accurately describes the system uncertainty in rotation and reduces the linearization error of system, which extends traditional CKF from Euclidean space to manifold. It not only inherits the advantages of invariant filtering in consistency, but also avoids the complex Jacobian calculation of high-dimensional matrix. To demonstrate the effectiveness of the proposed algorithm, we compare it with the state-of-the-art filtering-based VIO algorithms on Euroc datasets. And the results show that the proposed algorithm is effective in improving accuracy and robustness of estimation. Copyright © 2019, The Authors. All rights reserved.

关键词： Kalman filters

Design and Analysis of the Cooling Effect of the Temperature-Controlled Pile (Tcp) in Permafrost Regions

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SSRN 2022年

作者： Sun, Zhaohui Liu, Jiankun Hu, Tianfei You, Tian Fang, Jianhong School of Civil Engineering Sun Yat-sen University Southern Marine Science and Engineering Guangdong Laboratory Zhuhai519082 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Qinghai Research Institute of Transportation Xining810001 China

To accelerate the refreezing time of cast-in-place piles in permafrost regions and improve their long-term stability, this paper proposes a novel TCP based on solar refrigeration. The TCP consists of a solar power system (SPS), a vapor compression refrigeration system (VCRS), and a pile. Then, the cooling effect of TCP was carried out by the model test and the numerical simulation. The model test results show that both the evaporating temperature and the condensing temperature are positively correlated with the ambient temperature, but the coefficient of performance (COP) is negatively correlated with the ambient temperature. The numerical simulation results show the TCP can significantly shorten the refreezing time. The higher the mean annual ground temperature (MGAT), the more significant the acceleration effect. With the increase in the TCP working time, the pile wall permafrost temperature tends to be stable, and the cooling radius increases continuously. The TCP can restrain the degradation rate of the permafrost table, which can be further reduced by increasing the refrigeration power and the refrigeration tube space. The tangential freezing force between the frozen soil and the pile foundation is enhanced by the cooling effect of TCP and is stronger when it is close to the middle of the pile. The TCP bearing capacity is more than 1.5 times that of a traditional pile (TP). The effect of improving the bearing capacity of the pile foundation can be achieved by increasing the refrigeration power and refrigeration tube space. Therefore, TCP can be applied to pile engineering of high-speed railways and highways in permafrost regions. © 2022, The Authors. All rights reserved.

关键词： Piles

Influence of External structure and Internal Stacking on Wind Load Characteristics of Large Span Spherical Shell structure

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SSRN 2023年

作者： Liu, Xiaobing Chen, Anjie Yang, Qun Feng, Bin Tian, Xuedong 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

In order to study the wind load characteristics of the large span spherical shell structure, a rigid model pressure test was conducted in a wind tunnel laboratory to study the effects of different external structures and internal stacking forms on wind loads of a spherical shell structure in an actual project. The variation laws of the shape factor and the integral force coefficient of the spherical shell structure under different test cases are compared and analyzed. The results show that the shape factor of the spherical shell structure is only affected near the interference when the transfer station and trestle are arranged. When the two spherical shell structures are arranged in series and the adjacent spherical shell structure is located upstream, the shape factor of the spherical shell structure is most affected, and there is a significant reduction effect at the bottom of the windward surface. Compared with the external structure, the influence of different internal stacking forms on the shape factor of the spherical shell structure is relatively weak. The interference effect of the adjacent spherical shell structure makes the stress situation of the spherical shell structure better than that of the spherical shell structure without the adjacent spherical shell structure in most wind directions. The integral force coefficient of the spherical shell structure is the highest when the internal stacking is full, and the lowest when there is no internal stacking. Therefore, the integral force coefficient of the spherical shell structure when the internal stacking is full can be used as a reference for the design of the frame of the spherical shell structure. © 2023, The Authors. All rights reserved.

关键词： Shells (structures)

Experimental Study on Fluctuating Aerodynamic Force and Wind Pressure Distribution Characteristics of Three Circular Cylinders Arranged Inline

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SSRN 2023年

作者： Liu, Xiaobing Jiang, Huimin Wang, Shibo Liu, Xiqiang Yang, Qun 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

The fluctuating aerodynamic force and wind pressure distribution characteristics of three circular cylinders arranged inline at different incidence angles and spacing ratios were studied via rigid model pressure measurement wind tunnel tests. The results were compared with those of a single cylinder. The Reynolds number is 6.4×104. The range of incidence angle α and spacing ratio L/D (the ratio of the center distance between adjacent cylinders to the diameter of the cylinder) are 0°~90° and 1.2~4.0, respectively. The spacing ratio and incidence angle greatly influence the fluctuating aerodynamic force coefficients and wind pressure coefficients. According to the spacing ratio, the fluctuating aerodynamic characteristics can be roughly divided into three states: small spacing ratios (1.2≤L/D≤2.0), medium spacing ratios (2.0 © 2023, The Authors. All rights reserved.

关键词： Circular cylinders