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Multi-Scale Feature Fusion Model for bridge Appearance Defect Detection

Big Data Mining and Analytics 2024年第1期7卷 1-11页

作者： Rong Pang Yan Yang Aiguo Huang Yan Liu Peng Zhang Guangwu Tang School of Computing and Artificial Intelligence Southwest Jiaotong UniversityChengdu 611756China China Merchants Chongqing Road Engineering Inspection Center Co. Ltd.Chongqing 400067China State Key Laboratory of Bridge Engineering Structural Dynamics Chongqing 400067China

Although the Faster Region-based Convolutional Neural Network(Faster R-CNN)model has obvious advantages in defect recognition,it still cannot overcome challenging problems,such as time-consuming,small targets,irregular shapes,and strong noise interference in bridge defect *** deal with these issues,this paper proposes a novel Multi-scale Feature Fusion(MFF)model for bridge appearance disease ***,the Faster R-CNN model adopts Region Of Interest(ROl)pooling,which omits the edge information of the target area,resulting in some missed detections and inaccuracies in both detecting and localizing bridge ***,this paper proposes an MFF based on regional feature Aggregation(MFF-A),which reduces the missed detection rate of bridge defect detection and improves the positioning accuracy of the target ***,the Faster R-CNN model is insensitive to small targets,irregular shapes,and strong noises in bridge defect detection,which results in a long training time and low recognition ***,a novel Lightweight MFF(namely MFF-L)model for bridge appearance defect detection using a lightweight network EfficientNetV2 and a feature pyramid network is proposed,which fuses multi-scale features to shorten the training speed and improve recognition ***,the effectiveness of the proposed method is evaluated on the bridge disease dataset and public computational fluid dynamic dataset.

关键词： defect detection Multi-scale Feature Fusion(MFF) Region Of Interest(ROl)alignment lightweight network

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Research on Temperature Effect Separation Method of bridge Deflection Monitoring Data Based on Complementary Ensemble Empirical Mode Decomposition and Fast Independent Component Analysis

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ce/papers 2025年第2期8卷 1722-1736页

作者： Chen, Yixin Liu, Hao Liu, Zhanghao Meng, Libo Liao, Jingbo State Key Laboratory of Bridge Engineering Structural Dynamics and Key Laboratory of Bridge Earthquake Resistance Technology for Transportation Industry Chongqing400067 China China Merchants Chongqing Communications Technology Research & Design Institute Co. Ltd. Chongqing400067 China Chongqing Wukang Technology Co. Ltd. Chongqing404100 China

bridge deflection monitoring signals encompass the responses of vehicle loads, temperature loads, and shrinkage creep of concrete, and the temperature effect of bridge deflection can mask the signal characteristics reflecting the bridge operational status, thereby influencing the bridge status assessment. This paper proposes a temperature effect separation method for bridge deflection monitoring data, based on complementary ensemble empirical mode decomposition (CEEMD) and fast independent component analysis (FastICA). First, the single-channel bridge deflection signal is decomposed into a series of intrinsic mode functions (IMFs) by using CEEMD;next, the energy entropy increment-based discriminant method is used for identifying and eliminating the false IMF components, and those IMF components with large energy entropy increments compose the input signal;finally, the input signal is separated via FastICA. Based on the separation results and periodic pattern of temperature change, the temperature difference effect of bridge deflection monitoring data is recognized and separated. The correlation coefficients between the simulation analysis results of the separated signals and the source signal are above 0.95. Furthermore, in-service bridge deflection monitoring data analysis results indicate that the correlation coefficient between the source signal and the separation signal, as well as the symmetrical measuring point signals, is greater than 0.95, which demonstrates the applicability and practicality of the method in engineering applications. © 2025 Ernst & Sohn GmbH.

关键词： Empirical mode decomposition

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On Klein tunneling of low-frequency elastic waves in hexagonal topological plates

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1139-1154页

作者： Yuxin YAO Yuansheng MA Fang HONG Kai ZHANG Tingting WANG Haijun PENG Zichen DENG School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710072China MIIT Key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical UniversityXi’an710072China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of TechnologyDalian116024Liaoning ProvinceChina

Incident particles in the Klein tunnel phenomenon in quantum mechanics can pass a very high potential *** the concept of tunneling into the analysis of phononic crystals can broaden the application *** this study,the structure of the unit cell is designed,and the low frequency(<1 k Hz)valley locked waveguide is realized through the creation of a phononic crystal plate with a topological phase transition *** defect immunity of the topological waveguide is verified,that is,the wave can propagate along the original path in the cases of impurities and ***,the tunneling phenomenon is introduced into the topological valley-locked waveguide to analyze the wave propagation,and its potential applications(such as signal separators and logic gates)are further explored by designing phononic crystal *** research has broad application prospects in information processing and vibration control,and potential applications in other directions are also worth exploring.

关键词： topological metamaterial elastic wave Klein tunneling valley-locked waveguide

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Layered metastructure containing freely-designed local resonators for wave attenuation

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Defence Technology（防务技术） 2024年第2期32卷 23-31页

作者： Yu Li Huguang He Jiang Feng Hailong Chen Fengnian Jin Hualin Fan State Key Laboratory for Disaster Prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing 210007China Rocket Force University of Engineering Xi'an 710025China Henan International Joint Laboratory of Dynamics of Impact and Disaster of Engineering Structures Department of Civil EngineeringNanyang Institute of TechnologyNanyang 473004China Guangxi Key Laboratory of Disaster Prevention and Engineering Safety and Key Laboratory of Disaster Prevention and Structural Safety of Ministry of EducationCollege of Civil Engineering and ArchitectureGuangxi UniversityNanning 530004China Research Center of Lightweight Structures and Intelligent Manufacturing State Key Laboratory of Mechanics and Control of Mechanical StructuresNanjing University of Aeronautics and AstronauticsNanjing 210016China

Combining periodic layered structure with three-dimensional cylindrical local resonators,a hybrid metastructure with improved wave isolation ability was designed and investigated through theoretical and numerical *** metastructure is composed of periodic rubber layers and concrete layers embedded with three-dimensional resonators,which can be freely designed with multi local resonant frequencies to attenuate vibrations at required frequencies and widen the attenuation *** metastructure can also effectively attenuate seismic *** with layered rubber-based structures,the metastructure has more excellent wave attenuation effects with greater attenuation and wider bandgap.

关键词： Layered metastructure Local resonator Wave attenuation

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Comparative Analysis of ARIMA and LSTM Model-Based Anomaly Detection for Unannotated structural Health Monitoring Data in an Immersed Tunnel

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Computer Modeling in engineering & Sciences 2024年第5期139卷 1797-1827页

作者： Qing Ai Hao Tian Hui Wang Qing Lang Xingchun Huang Xinghong Jiang Qiang Jing School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Key Laboratory of Road and Bridge Detection and Maintenance Technology of Zhejiang Province Hangzhou311305China Zhejiang Scientific Research Institute of Transport Hangzhou310023China State Key Laboratory of Coal Mine Dynamics and Control Chongqing UniversityChongqing400044China Hong Kong-Zhuhai-Macao Bridge Authority Zhuhai519060China

structural Health Monitoring(SHM)systems have become a crucial tool for the operational management of long *** immersed tunnels exposed to both traffic loads and the effects of the marine environment,efficiently identifying abnormal conditions from the extensive unannotated SHM data presents a significant *** study proposed amodel-based approach for anomaly detection and conducted validation and comparative analysis of two distinct temporal predictive models using SHM data from a real immersed ***,a dynamic predictive model-based anomaly detectionmethod is proposed,which utilizes a rolling time window for modeling to achieve dynamic *** the assumption of temporal data similarity,an interval prediction value deviation was employed to determine the abnormality of the ***,dynamic predictive models were constructed based on the Autoregressive Integrated Moving Average(ARIMA)and Long Short-Term Memory(LSTM)*** hyperparameters of these models were optimized and selected using monitoring data from the immersed tunnel,yielding viable static and dynamic predictive ***,the models were applied within the same segment of SHM data,to validate the effectiveness of the anomaly detection approach based on dynamic predictive modeling.A detailed comparative analysis discusses the discrepancies in temporal anomaly detection between the ARIMA-and LSTM-based *** results demonstrated that the dynamic predictive modelbased anomaly detection approach was effective for dealing with unannotated SHM *** a comparison between ARIMA and LSTM,it was found that ARIMA demonstrated higher modeling efficiency,rendering it suitable for short-term *** contrast,the LSTM model exhibited greater capacity to capture long-term performance trends and enhanced early warning capabilities,thereby resulting in superior overall performance.

关键词： Anomaly detection dynamic predictive model structural health monitoring immersed tunnel LSTM ARIMA

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Tailored energy absorption for a novel auxetic honeycomb structure under large deformation

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 63-80页

作者： Xiuhui Hou Bin Wang Zichen Deng School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710129China MIIT Key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical UniversityXi'an 710072China School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China

In comparison to conventional hexagonal honeycomb structures,auxetic metamaterials with re-entrant configurations have exhibited superior mechanical properties in terms of energy *** further enhance the energy absorption capacity of these materials,a novel re-entrant honeycomb configuration,named novel auxetic re-entrant honeycomb(NARH),is developed by incorporating“<>”-shaped cell walls into the conventional auxetic re-entrant honeycomb(ARH).Two analytical models for the plateau stress are formulated to consider the plastic deformation of NARH during quasi-static compression and the dynamic impact using the linear momentum ***-static compression tests on 3D printed NARH honeycomb specimens and finite element simulations are performed to verify the effectiveness of the theoretical *** exhibits higher plateau stresses compared with ARH during compression,which can be attributed to the presence of more plastic hinges formed in *** hinges,the embedded parts with inclined cell walls,not only improve stability by forming stable triangles during compression but also enhance the energy absorption capacity.A parametric study is conducted to analyze the effect of impact velocity,thickness,and incline angle of cell walls on *** simulations demonstrate higher sensitivity of the mechanical properties to impact velocity and cell wall *** ribs to the“<>”-shaped cell walls in NARH further reduces the initial peak force during dynamic crushing while maintaining high energy *** research provides valuable guidelines for the design of energy absorption metamaterials.

关键词： absorption walls shaped

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In-Plane Dynamic Crushing Behaviors of a Vertex-Based Hierarchical Auxetic Honeycomb

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Acta Mechanica Solida Sinica 2024年第1期37卷 53-62页

作者： Yichen Zan Xiuhui Hou Zichen Deng School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China MIIT Key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical UniversityXi'an 710072China School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China

Auxetic metamaterials,which exhibit the negative Poisson’s ratio(NPR)effect,have found wide applications in many engineering ***,their high porosity inevitably weakens their bearing capacity and impact *** improve the energy absorption efficiency of auxetic honeycombs,a novel vertex-based hierarchical star-shaped honeycomb(VSH)is designed by replacing each vertex in the classical star-shaped honeycomb(SSH)with a newly added self-similar *** analytical model is built to investigate the Young’s modulus of VSH,which shows good agreement with experimental results and numerical *** in-plane dynamic crushing behaviors of VSH at three different crushing velocities are investigated,and empirical formulas for the densification strain and plateau stress are *** results reveal more stable deformation modes for VSH,attributed to the addition of self-similar star-shaped ***,compared with SSH under the same relative densities,VSH exhibits better specific energy absorption and higher plateau ***,VSH is verified to be a better candidate for energy absorption while maintaining the auxetic *** study is expected to provide a new design strategy for auxetic honeycombs.

关键词： Vertex-based hierarchical star-shaped honeycomb Auxetic honeycomb Energy absorption Plateau stress Negative Poisson's ratio

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Research on Method of Post-Speed Limit Value Determining of Freeway 21

Research on Method of Post-Speed Limit Value Determining of ...

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21st COTA International Conference of Transportation Professionals: Advanced Transportation, Enhanced Connection, CICTP 2021

作者： Guo, Kai Melkisedek Coulibaly, Nathanael Cai, Jing Wang, Xiao-Fei State Key Laboratory of Bridge Engineering Structural Dynamics Key Laboratory of Bridge Earthquake Resistance Technology Ministry of Communications Chongqing China

ISBN: (纸本)9780784483565

To reduce the probability and severity of accidents, improve traffic capacity, and ensure efficient operation of traffic flow, the speed limit has become an important means of highway traffic management. Based on the systematic analysis of the existing methods to determine the speed limit value, a posted speed limit value determining model has been proposed in the paper. First, the flat curve, the vertical curve, and the free flow of traffic are taken as reference values for limiting vehicle speed. Second, after comprehensively considering the influence of roadbed cross-section, traffic composition, pavement conditions, large structures, traffic accidents, and operating speed coordination as a correction factor, a multi-factor speed limit value determination model is constructed and verified by engineering examples. © 2021 CICTP 2021: Advanced Transportation, Enhanced Connection - Proceedings of the 21st COTA International Conference of Transportation Professionals. All rights reserved.

关键词： Highway accidents

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A Suggestion to Take Seismic Hazard Characteristics into Account in Design of Highway bridges 9

A Suggestion to Take Seismic Hazard Characteristics into Acc...

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9th International Technical Conference on Frontiers of Hydraulic and Civil engineering Technology, HCET 2024

作者： Tao, Xiaxin Tao, Zhiguo Tao, Zhengru Liu, Haiming Wang, Liyuan Wang, Futong State Key Laboratory of Bridge Engineering Structural Dynamics China Merchants Chongqing Communication Research & Design Institute Co. Ltd Chongqing400067 China Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering Mechanics CEA Harbin150080 China Key Laboratory of Earthquake Disaster Mitigation Ministry of Emergency Management Harbin150080 China Heilongjiang University of Science and Technology Harbin150027 China Heilongjiang University Harbin150080 China

ISBN: (纸本)9781643685595

The seismic hazard characteristics are emphasized in this paper. The three K values from the seismic ground motion parameters zoning map 2015 (SHM 2015) of China are introduced, which are the ratios of the frequent, rare and very rare peak ground motion accelerations to the basis peak ground motion acceleration. The data of the three K values on 95932 ground points in mapping of the SHM 2015 are collected and analyzed. However, in a industry standard, the specification for seismic design of highway bridges (SSDHB), there is no corresponding regulation on how to determine the specific values on engineering site. The inconsistency of these two standards has brought some confusion and inconvenience to the seismic design of highway bridges. A site specified importance factor for updating of the specification for seismic design of highway bridges 2020 is presented to take into account the hazard characteristics from a zoning map of K values. Finally, a scheme to determine the factor value for seismic design of a bridge with its type and the site location is suggested. © 2024 The Authors.

关键词： Zoning

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Symplectic analysis for regulating wave propagation in a one-dimensional nonlinear graded metamaterial

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Applied Mathematics and Mechanics(English Edition) 2023年第5期44卷 745-758页

作者： Yunping ZHAO Xiuhui HOU Kai ZHANG Zichen DENG Department of Applied Mathematics Northwestern Polytechnical UniversityXi’an 710072China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an 710072China Ministry of Industry and Information Technology Key Laboratory of Dynamics and Control of Complex SystemsNorthwestern Polytechnical UniversityXi’an 710072China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of TechnologyDalian 116024China

An analytical method,called the symplectic mathematical method,is proposed to study the wave propagation in a spring-mass chain with gradient arranged local resonators and nonlinear ground *** with the linearized perturbation approach,the symplectic transform matrix for a unit cell of the weakly nonlinear graded metamaterial is derived,which only relies on the state *** results of the dispersion relation obtained with the symplectic mathematical method agree well with those achieved by the Bloch *** is shown that wider and lower frequency bandgaps are formed when the hardening nonlinearity and incident wave intensity ***,the displacement response and transmission performance of nonlinear graded metamaterials with finite length are *** dual tunable effects of nonlinearity and gradation on the wave propagation are explored under different excitation *** small excitation frequencies,the gradient parameter plays a dominant role compared with the *** reason is that the gradient tuning aims at the gradient arrangement of local resonators,which is limited by the critical value of the local resonator *** contrast,for larger excitation frequencies,the hardening nonlinearity is dominant and will contribute to the formation of a new bandgap.

关键词： symplectic mathematical method nonlinear graded metamaterial tunable bandgap

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