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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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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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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

引用

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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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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Dynamic mechanical characteristics and anti-thaw measures of warm frozen soil

Transportation Engineering

引用

Transportation engineering 2025年 20卷

作者： Liu, Jiankun Sun, Zhaohui Cui, Yinghui Hu, Tianfei Tai, Bowen School of Civil Engineering & State Key Laboratory for Tunnel Engineering Sun Yat-Sen University Guangzhou519082 China Institute of Future Civil Engineering Sciences and Technology Chongqing Jiaotong University Chongqing 400074 China China State Railway Group Co. Ltd Beijing 100844 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China State Key Laboratory of Cryospheric Science and Frozen Soil Engineering Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Lanzhou730000 China

Permafrost is widely distributed across the Qinghai-Tibet Plateau, and under the influence of climate warming, low-temperature frozen soil is gradually degrading into warm frozen soil. The ratio of ice to unfrozen water in warm frozen soil is highly sensitive to temperature changes, resulting in significant instability in its mechanical properties. To ensure the long-term stability of structures overlying permafrost foundations, conducting research on the mechanical characteristics of warm frozen soil and proposing effective measures to mitigate thaw settlement are crucial. This paper presents the research progress of our team in the field of warm frozen soil dynamics. Using a dynamic triaxial apparatus for frozen soil and a self-developed dynamic direct shear apparatus, we investigated the behavior of warm frozen soil under different temperatures, revealing the influence of temperature on its dynamic stress-strain relationship and dynamic parameters. The development of frozen soil creep theory is reviewed, and advancements in frozen soil dynamics research are summarized and discussed. This paper proposes the use of solar refrigeration technology to protect permafrost, introducing a solar-powered compression refrigeration device and its working principles. The active cooling performance of the device was tested through model experiments and field trials. Additionally, the design and construction techniques of all-season cooling embankments are discussed, providing theoretical and technical support for the stability control of subgrade engineering in permafrost regions. © 2025 The Author(s)

关键词： Permafrost

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Effect of Tamping Energy on the Reinforcement of a High Embankment Filled with Soil-Rock 4

Effect of Tamping Energy on the Reinforcement of a High Emba...

引用

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

作者： Hou, Licheng Yang, Guangqing Jin, Jing Lu, Huali Zhang, Ouyang Third Construction Engineering Company Ltd. China Construction Second Engineering Bureau Ltd. Beijing100070 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang Hebei050043 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang Hebei050043 China School of Civil Engineering Hebei University of Science and Technology Shijiazhuang Hebei050018 China China State Construction Engineering Corp. Ltd Beijing100020 China

Through dynamic compaction tests with tamping energies of 1500, 2000, and 2500 kN•m of an embankment section in the PingShan-ZanHuang Expressway, the compression deformation behavior of the tamping settlement, soil deformation around the tamping rammer, consolidation depth, and dynamic stress of dynamic compaction were comprehensively tested. Comparative analyses of field data under three different tamping energies suggested that the optimal tamping energy, number of strikes, and vertical effective tamping depth for this embankment are 2000 kN•m, six, and 5 m, respectively. The field test data proving that dynamic compaction has a significant effect on this embankment. © Published under licence by IOP Publishing Ltd.

关键词： Embankments

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Organic solar cells: beyond 20%

引用

Science China Materials 2025年第6期68卷 1689-1701页

作者： Ma, Ruijie Luo, Zhenghui Zhang, Youdi Zhan, Lingling Jia, Tao Cheng, Pei Yan, Cenqi Fan, Qunping Liu, Shengjian Ye, Long Zhang, Guangye Xu, Xiaopeng Gao, Wei Wu, Yue Wu, Jiaying Li, Yuxiang Liu, Yuhang Liu, Feng Song, Jiali Chen, Haiyang Chen, Weijie Zhang, Xin Liu, Yahui Yuan, Jun Liu, Quan Kan, Zhipeng Yin, Hang Li, Xiaojun Ma, Yunlong Deng, Dan Zhu, Lei Huo, Yong Fan, Baobin Fu, Huiting Liao, Xunfan Hu, Hanlin Li, Chao Yu, Runnan Hu, Huawei Yao, Zhaoyang Cai, Yunhao Qian, Deping Cui, Yong Yao, Huifeng Xu, Bowei Kan, Bin Gao, Ke Duan, Chunhui Hu, Xiaotian Sun, Huiliang School of Chemistry and Chemical Engineering Gannan Normal University Ganzhou341000 China Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and Devices The Hong Kong Polytechnic University 999077 Hong Kong Guangdong Provincial Key Laboratory of New Energy Materials Service Safety Shenzhen Key Laboratory of New Information Display and Storage Materials College of Materials Science and Engineering Shenzhen University Shenzhen518060 China Key Laboratory of Advanced Green Functional Materials College of Chemistry Changchun Normal University Changchun130032 China Key Laboratory of Organosilicon Chemistry and Material Technology Ministry of Education Zhejiang Key Laboratory of Organosilicon Material Technology College of Material Chemistry and Chemical Engineering Hangzhou Normal University Hangzhou311121 China School of Optoelectronic Engineering Guangdong Polytechnic Normal University Guangzhou510665 China College of Polymer Science and Engineering National Key Laboratory of Advanced Polymer Materials Sichuan University Chengdu610065 China State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong University Xi’an710049 China Guangzhou510006 China Tianjin University Tianjin300350 China College of New Materials and New Energies Shenzhen Technology University Shenzhen518118 China College of Chemical Engineering Sichuan University Chengdu610065 China Xiamen Key Laboratory of Optoelectronic Materials and Advanced Manufacturing Institute of Luminescent Materials and Information Displays College of Materials Science and Engineering Huaqiao University Xiamen361021 China Laboratory of Advanced Optoelectronic Materials College of Chemistry Chemical Engineering and Materials Science Soochow University Suzhou215123 China Guangzhou511400 China School of Materials Science and Engineering Xi’an University of Science and Technology Xi’an710054 China Shanghai200240 China Hangzhou International Innovation Institute Beihang U

Organic solar cells (OSCs) have experienced remarkable performance progress up to 20% benchmark power conversion efficiency (PCE) in past years. Considering the © Science China Press 2025.

关键词： Product design

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Illumination robust loop closure detection with the constraint of pose

arXiv

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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

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

arXiv

引用

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

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