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Analytical Solutions of Cracks Emanating from an Elliptic Hole in an Infinite Plate under Tension

Chinese Journal of Mechanical Engineering 2014年第5期27卷 1057-1063页

作者： LIU Shuhong DUAN Shijie Department of Engineering Mechanics Shijiazhuang Tiedao University The Key Laboratory for Health Monitoring and Control of Large Structures of Hebei Province Department of Adult Education Shijiazhuang Tiedao University

It is a common phenomenon that the cracks originating from a hole can cause structural damage in ***,the fracture mechanics studies of hole edge crack problems are not *** problem of an elliptical hole with two collinear edge cracks of unequal length in an infinite plate under uniform tension at infinity is *** on the complex variable method,the analytical solutions of stress functions and stress intensity factors are *** stress distribution along the axes and the edge of the elliptical hole is given *** numerical results show that there is obvious stress concentration near the hole and cracks,and the stresses tend to applied loads at distances far from the defect,which conform to Saint-Venant’s ***,the stress functions are proved to be *** special conditions,the present configuration becomes the Griffith crack,two symmetrical cracks emanating from an elliptical hole,two cracks of unequal length emanating from a circular hole,a crack at the edge of a circular hole,or a crack emanating from an elliptical *** with available results,stress intensity factors for these special shapes of ellipses and cracks show good *** stress intensity factor for two cracks of unequal length at the edge of an elliptical hole increases with the crack length and the major-to-minor axis ratio of the elliptical *** stress distribution in an infinite plate containing an elliptic hole with unsymmetrical cracks is given for the first time.

关键词： hole crack stress distribution stress intensity factor

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Analysis of transverse thermal regime difference of high-speed railway roadbed in seasonally frozen regions 15

Analysis of transverse thermal regime difference of high-spe...

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15th International Conference of the International Association for Computer Methods and Advances in Geomechanics, IACMAG 2017

作者： Zhang, Yuzhi Wen, An Cheng, Boyuan Key Laboratory for Health Monitoring and Control of Large Structures in Hebei Province Shijiazhuang Tiedao University Shijiazhuang Hebei050043 China

The transverse thermal regime differences are widespread for high-speed railway roadbed in seasonally frozen regions. Based on the monitored data of four typical roadbed sections from Harbin-Dalian high-speed railway in seasonally frozen regions of China, the external influence and heat absorption of roadbed different parts are studied quantitatively through the comparisons of the temperature amplitude and average temperature, and then the characteristics of the frost penetration development are analyzed. The temperature variation laws of the coldest and hottest months with depth are also analyzed. On the basis of the above analysis, the influence factors and potential hazards of the transverse differences are discussed. It is stated that: the west shoulders are most influenced by the external environment. The coldest and warmest month temperatures at a certain depth are characterized by a spindle shape. The increase of the latitude and roadbed height may aggravate the transverse thermal regime difference. In addition, the roadbed transverse thermal difference may induce the uneven roadbed deformation, hence, the roadbed stability and the ride comfort of track structure maybe threated. Therefore, the relevant monitoring and deformation mechanics studies should be further reinforced. © 2017 15th International Conference of the International Association for Computer Methods and Advances in Geomechanics

关键词： Deformation

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Construction of stability monitoring and evaluation system for high-speed railway roadbed in cold regions 8

Construction of stability monitoring and evaluation system f...

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8th International Conference on Structural health monitoring of Intelligent Infrastructure, SHMII 2017

作者： Zhang, Yuzhi Sun, Baochen Zhao, Weigang Wen, An The Key Laboratory for Health Monitoring and Control of Large Structures in Hebei Province Shijiazhuang Tiedao University Shijiazhuang Hebei050043 China

ISBN: (纸本)9781925553055

Along with the development of economy, the high-graded transportation line project are extending towards the cold regions gradually. The high-speed railway (HSR) in cold regions requires extreme high stability, thus the rigorous enigineering demands challenge the roadbed stability severely. The construction of the automatic monitoring and evaluation system of the HSR roadbed in cold regions, to master the safety conditions in real time, will guarantee the safe operation of high-speed train strongly. Through the characteristics analysis of the HSR roadbed in cold regions, the monitoring indices, static deformation combined with dynamic responses, are determined. The layout plan of monitoring points, which integrates the transverse discontinuity with horizontal continuity, is put forward. On the basis of conquering the continous high-precision collection sensors and technology suitable for the severe environment in cold regions, the automatic continous monitoring system of the HSR roadbed is developed, and the evaluation method of roadbed stability based on the on-site data information mining and numerical model is built. The monitoring system and stability method have realized the continous monitoring and stability evaluation of the Harbin-Dalian HSR under the water-heat-load combined action. This will be conductive to provide the scientific support for the stability change mechanism, the operation and maintenance of the HSR roadbed in cold regions. © 2017 International Society for Structural health monitoring of Intelligent Infrastrucure. All rights reserved.

关键词： Railroads

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A long-term vertical displacement prediction method of concrete bridges based on meteorological shared data and optimized GRU model

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Measurement: Journal of the International Measurement Confederation 2025年 253卷

作者： Wang, Xu Xie, Guilin Liu, Wentao Kong, Hu Gao, Yang State Key Laboratory of Mountain Bridge and Tunnel Engineering Chongqing Jiaotong University Chongqing400074 China School of Civil Engineering Chongqing Jiaotong University Chongqing400074 China China Merchants Chongqing Road Engineering Inspection Center Co. Ltd Chongqing400067 China Department of Civil and Transportation Engineering Hohai University Nanjing210098 China Key Laboratory for Structure Health Monitoring and Control in Hebei Province Shijiazhuang Tiedao University Shijiazhuang050043 China

Based on data from the meteorological shared data platform, this study proposes a method for predicting the long-term vertical displacement (VD) of concrete bridges by integrating the Northern Goshawk Optimization (NGO) algorithm with the Gated Recurrent Unit (GRU) network. This method can be employed to safely assess concrete bridges and recover missing VD data. Specifically, it uses historical meteorological information and time information provided by the meteorological shared data platform (European Centre for Medium-Range Weather Forecasts) to generate the input parameters of the GRU model. It then employs the long-term VD data from the concrete bridge structural health monitoring system to produce the output parameters of the GRU model. Moreover, the hyperparameters for the GRU model training are optimized using the NGO algorithm. Four NGO-GRU models with different input conditions are proposed, taking the long-term VD prediction of a prestressed concrete bridge as a case study and considering the correlation between different meteorological factors and VD and the long-term time-dependent effects on concrete structures. Through a comparative analysis of the model's prediction performance of multiple sensors under different conditions, it is found that the NGO-GRU model achieved the best prediction performance when using a combination of air temperature, time information, air pressure, solar radiation intensity, and wind speed as inputs, with a prediction error of less than 6.00%. Furthermore, compared with the benchmark models, the NGO-GRU model demonstrated the highest accuracy in VD prediction. Under the optimal input conditions, the prediction performance of the NGO-GRU model improved by 16.46% to 46.17% compared with the other models, validating the robustness and effectiveness of the proposed method. © 2025 Elsevier Ltd

关键词： Concrete bridges Long-term monitoring Meteorological shared data Northern goshawk optimization-based GRU Structural health monitoring Vertical displacement

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Effective concrete surface crack detection based on extreme learning machine 8

Effective concrete surface crack detection based on extreme ...

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8th International Conference on Structural health monitoring of Intelligent Infrastructure, SHMII 2017

作者： Wang, Baoxian Zhao, Weigang Zhang, Hao Wang, Xinmin Zhang, Guangyuan Structural Health Monitoring and Control Institute Shijiazhuang Tiedao University Shijiazhuang050043 China Key Laboratory for Health Monitoring and Control of Large Structures Shijiazhuang050043 China Collaborative Innovation Center of Large Infrastructure Disaster Prevention and Reduction of Hebei Province China

ISBN: (纸本)9781925553055

Concrete surface crack detection has been an important field for the safety of civil engineering structure. However, under the background of high-density data acquiring demand, the existing crack detecting methods could not obtain the favorable efficiency and capability. In this work, we present a novel concrete surface crack detector for efficiently dealing with the massive crack images. Specifically, discrete cosine transformation is firstly utilized to extract the frequency domain characteristics of concrete surface images. Then, with the calculated image frequency features, an emergent learning technique (i.e., Extreme Learning Machine) is exploited to find the optimal separate hyper-plane between the crack object and backgrounds. Experiments on the crack images from the railway ballast-less track slab validate the effectiveness of the proposed method. © 2017 International Society for Structural health monitoring of Intelligent Infrastrucure. All rights reserved.

关键词： Frequency domain analysis

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Analysis of void-disease detection in ballastless track of high-speed railway based on directional filter 8

Analysis of void-disease detection in ballastless track of h...

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8th International Conference on Structural health monitoring of Intelligent Infrastructure, SHMII 2017

作者： Yang, Y. Zhao, W.G. Du, Y.L. Tian, X.S. School of Electrical and Electronic engineering Shijiazhuang Tiedao University Shijiazhuang China Key Laboratory for Health Monitoring and Control of Large Structures in Hebei Province Shijiazhuang Tiedao University Shijiazhuang China

ISBN: (纸本)9781925553055

Owing to the concealment of void disease in cement-asphalt (CA) mortar and the requirements for rapidness, ground penetrating radar (GPR) has a good application prospect in detecting disease on a high-speed railway. Track slab, the covering of the CA mortar layer, is a multi-layer reinforced concrete structure;strong reflection of reinforcement makes disease identification difficult. To solve this problem, directional models were established to study the feature difference of echoes between reinforcement and void disease, and a horizontal filter based on curvelet transform was proposed to identify the void disease in CA mortar. Finally, forward simulation was conducted to validate the performance of the presented algorithm. Results show that the horizontal filter method contributes to the identification of void diseases in the CA mortar layer which were located in the middle of the reinforcement group. This study promotes the application of GPR on disease detection in a high-speed railway. © 2017 International Society for Structural health monitoring of Intelligent Infrastrucure. All rights reserved.

关键词： Ground penetrating radar systems

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Effects of the reattachment on dry galloping in the critical Reynolds number range 9

Effects of the reattachment on dry galloping in the critical...

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9th Asia Pacific Conference on Wind Engineering, APCWE 2017

作者： Ma, Wenyong Liu, Qingkuan Liu, Xiaobing Key Laboratory for Health Monitoring and Control of Large Structure Shijiazhuang Tiedao University Hebei province China Department of Wind Science and Engineering Shijiazhuang Tiedao University Shijiazhuang City Hebei Province China

large amplitude vibrations of circular cylinders in the critical Reynolds number range are reproduced in wind tunnels. Displacements and wind pressure for the cylinders are measured synchronously to reveal the characteristics of aerodynamic force for the vibrating cylinders in a Reynolds number range where flow re-attaches on the rear of the cylinder. Effects of these reattachments on the aerodynamic forces and the vibrations are discussed. The results show that the reattachment can produce unsteady aerodynamic force and excite large amplitude vibration when it forms unstable separation bubble at the early critical Reynolds number range. Once it develops stable separation bubble, the reattachment mitigates the vibrations by creating strong negative aerodynamic damping. © 9th Asia Pacific Conference on Wind Engineering, APCWE 2017. All Rights Reserved.

关键词： Circular cylinders

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Damage evolution analysis of rock under Uniaxial compression and Brazilian splitting based on discrete element method 10

Damage evolution analysis of rock under Uniaxial compression...

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2020 10th Chinese Geosynthetics Conference and International Symposium on Civil Engineering and Geosynthetics, ISCEG 2020

作者： De-Kang, Li Hao-Ran, Li Meng, Liu Zi-Heng, Wang Zheng, Li Structural Health Monitoring and Control Institute Shijiazhuang Tiedao University Shijiazhuang Hebei050043 China Key Laboratory for Health Monitoring and Control of Large Structures Shijiazhuang Tiedao University Shijiazhuang Hebei050043 China Second Geological Team of Hebei Coalfield Geological Bureau Xingtai Hebei054001 China

In order to better analyze the mechanical behavior of rock in uniaxial compression and Brazilian splitting, numerical model was established according to laboratory test by PFC2D particle flow program, and the simulation results were compared with the experimental results. The results show that when the rock reaches the peak stress, the failure curve of cement appears an obvious turning point, and the failure rate of cement *** compressive strength of rock is much greater than the tensile strength under compression condition. The preloading method is more detailed for experimental restoration, and it provides certain reference significance for rock simulation in the future. © The Authors, published by EDP Sciences 2020.

关键词： Rocks

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Effective intrusion detection for railway scene based on video analytics 8

Effective intrusion detection for railway scene based on vid...

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8th International Conference on Structural health monitoring of Intelligent Infrastructure, SHMII 2017

作者： Li, Y.D. Lin, Y.B. Zhang, C. Zhao, W.G. School of Electronic and Information Engineering North China University of Technology Beijing100041 China Key Laboratory for Health Monitoring and Control of Large Structures Shijiazhuang050043 China Institute of Structure Health Monitoring and Control Shijiazhuang Tiedao University Shijiazhuang050043 China

ISBN: (纸本)9781925553055

Intrusion detection for railway scene is the essential method to avoid railway accidents caused by the invasions of pedestrians, falling rocks, animals, etc. In this paper, an automatic computer-vision based scheme is proposed to detect abnormal events in the track area, and send pre-warning signals to the control center. First, background is estimated by Gaussian mixture models, and the targets are obtained from the difference image between foreground and background combining with threshold, morphological filtering and connected component labeling. Second, mean shift algorithm is used to track the invasive target. To improve the tracking robustness, Histogram of Oriented Gradient (HOG) is chosen as the feature space to establish the target model, which has strong discriminative ability and robustness over illumination variation and small distortion of object. Third, behavior analysis is conducted based on target trajectory to determine whether there exist abnormal events in the track area. If yes, alarm messages with high-definition pictures are sent to control center. The proposed method has been operated on K141 spot of Shuohuang railway. The practical running results show that the intrusion detection system is effective and robust in railway scene. © 2017 International Society for Structural health monitoring of Intelligent Infrastrucure. All rights reserved.

关键词： Intrusion detection

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Analysis on a novel reflective intensity modulated fiber optic temperature sensor

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World Forum on Smart Materials and Smart structures Technology, SMSST 07

作者： Dai, Jingyun Zhang, Wentao Sun, Baochen Du, Yanliang Key Lab. of Structure Health Monitoring and Control of Hebei Province Shijiazhuang Railway Institute Shijiazhuang Hebei China State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences Beijing China

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