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

SSRN

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

引用

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

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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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Indentation Responses of Piezoelectric Semiconductors

SSRN

引用

SSRN 2023年

作者： Liu, Jinxi Gao, Shijing Zhang, Zeran 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

In this paper, the indentation responses of a piezoelectric semiconductor (PSC) half-space by an insulating and rigid spherical indenter are investigated. It is assumed that the contact area between the indenter and the PSC is frictionless. Based on the Hankel integral transformation, the considered indentation problem is reduced to a pair of dual integral equations. Due to the complexity of the coupled governing differential equations, the explicit closed-form expressions for the PSC indentation responses cannot be derived like the piezoelectric counterparts. Therefore, the dual integral equations are converted into the Fredholm integral equation of the second kind, which is numerically solved to determine the concerned responses. These responses include the relationships of the indentation force, the electric potential and the change of carrier concentration with the indentation depth. The numerical results show that the semiconducting property has a significant influence on the indentation characteristics. In addition, the three-dimensional finite element simulations are carried out to validate the theoretical results computed by the singular integral equation method. It turns out that the two results are well consistent. The distributions of the stress and electric potential near the contact area are simulated by finite element method to reveal the effect of the steady carrier concentration. The obtained findings are useful for understanding the interaction between piezoelectricity and semiconducting property. © 2023, The Authors. All rights reserved.

关键词： Indentation

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

SSRN

引用

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

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

SSRN

引用

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)

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

SSRN

引用

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

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Experimental Study on Shear Strength Characteristics of Frozen Soil - Cast-in-Situ Concrete Interface

SSRN

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SSRN 2022年

作者： Sun, Tiecheng Dong, Chuangqi Zhang, Jiao Zong, Zihang Wu, Kai State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Key Laboratory of Roads and Railway Engineering Safety Control Ministry of Education Shijiazhuang050043 China Hebei Province Technology and Innovation Center on Intelligent Construction of Infrastructure Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China

The roughness of contact surface is closely related to the friction coefficient and shear strength characteristics of pile-soil interface. At present, there is no recognized and unified quantitative characterization method of contact surface roughness. In this paper, the roughness formula is corrected in combination with the proposed form factor, and the low temperature direct shear test of the frozen soil-cast-in-situ concrete interface is carried out. The influence of several test factors, such as contact surface roughness, normal pressure and moisture content of soil sample, on frozen shear strength of frozen soil-cast-in-situ concrete contact surface is analyzed. The test results show that: (a) The frozen shear strength at the contact surface is mainly determined by the cementation of ice cementation force, cohesion and the bite force between frozen soil and concrete. The roughness corrected by the form coefficient can accurately characterize the contribution of bite force to the frozen shear strength of the contact surface. (b) The primary and secondary order of the influence of test control factors on the frozen shear strength of contact surface is normal pressure > moisture content of soil sample > test temperature > roughness > dry density. The normal pressure and moisture content have a strong and significant influence on the test results, the influence of dry density is not significant, and the influence of test temperature and roughness is in the middle. (c) The frozen shear strength of the contact surface increases with the increase of roughness, but the increase of normal pressure can weaken the effect of roughness on the enhancement of shear strength. © 2022, The Authors. All rights reserved.

关键词： Temperature

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