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Journal of Magnesium and Alloys 2024年第1期12卷 361-383页

作者： Chao Xie Shijie Bai Xiao Liu Minghua Zhang Jianke Du The Faculty of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211P.R.China Key Laboratory of High Temperature Wear Resistant Materials Preparation Technology of Hunan Province Hunan University of Science and TechnologyXiangtan 411201P.R.China

In this study,a phase-field scheme that rigorously obeys conservation laws and irreversible thermodynamics is developed for modeling stress-corrosion coupled damage(SCCD).The coupling constitutive relationships of the deformation,phase-field damage,mass transfer,and electrostatic field are derived from the entropy *** SCCD localization induced by secondary phases in Mg is numerically simulated using the implicit iterative algorithm of the self-defined finite *** quantitative evaluation of the SCCD of a C-ring is in good agreement with the experimental *** capture the damage localization,a micro-galvanic corrosion domain is defined,and the buffering effect on charge migration is *** cases are investigated to reveal the effect of localization on corrosion acceleration and provide guidance for the design for resistance to SCCD at the crystal scale.

关键词： Phase field Mg alloys Stress-corrosion coupled damage damage localization Finite element method

Full-field out-of-plane vibration displacement acquisition based on speckle-projection digital image correlation and its application in damage localization

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International Journal of Mechanical System Dynamics 2022年第4期2卷 363-373页

作者： Shancheng Cao Jinwei Yan Haibo Nian Chao Xu School of Astronautics Northwestern Polytechnical UniversityXi'anChina Yangtze River Delta Research Institute of Northwestern Polytechnical University TaicangJiangsuChina China Electronic Product Reliability and Environmental Testing Research Institute GuangzhouChina Guangdong Provincial Key Laboratory of Electronic Information Products Reliability Technology GuangzhouChina

Stereo-digital image correlation(Stereo-DIC)has been widely explored for modal analysis in plate-type structures due to its noncontact and full-field ***,when the traditional stereo-DIC is adopted to capture the out-of-plane displacements,several challenging issues exist such as the development of surface speckles,asynchronous camera recording,and efficiency and accuracy degradation due to high computation ***,with the captured out-of-plane displacements,effective and efficient evaluation of the high spatial resolution mode shapes and their application to damage localization are also critical *** tackle these issues,a speckle-projection DIC technique using a single high‐speed camera is proposed to obtain the out-of-plane vibration ***,an enhanced peak-picking modal analysis method is adopted to enhance the estimation accuracy and efficiency of mode *** addition,the low‐rank property of mode shapes in an intact state and the spatial sparse property of damage locations are harnessed for the detection of damage positions without requiring reference data on the healthy ***,the modal analysis and damage localization results based on the proposed speckle-projection DIC are compared with those of the traditional two-camera stereo-DIC technique to verify its feasibility and *** is found that the differences in the identified resonant frequencies between these two methods are smaller than 1%for higher ***,the proposed speckle-projection DIC has the same accuracy as the traditional two-camera stereo-DIC in terms of measurement accuracy,mode shape estimation,and damage localization.

关键词： damage localization digital image correlation low-rank property modal analysis out-of-plane displacement

Modal Strain Energy Based Structural damage localization for Offshore Platform using Simulated and Measured Data

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Journal of Ocean University of China 2014年第3期13卷 397-406页

作者： WANG Shuqing LIU Fushun ZHANG Min College of Engineering Ocean University of China

Modal strain energy based methods for damage detection have received much attention. However, most of published articles use numerical methods and some studies conduct modal tests with simple 1D or 2D structures to verify the damage detection algorithms. Only a few studies utilize modal testing data from 3D frame structures. Few studies conduct performance comparisons between two different modal strain energy based methods. The objective of this paper is to investigate and compare the effectiveness of a traditional modal strain energy method(Stubbs index) and a recently developed modal strain energy decomposition(MSED) method for damage localization, for such a purpose both simulated and measured data from an offshore platform model being used. Particularly, the mode shapes used in the damage localization are identified and synthesized from only two measurements of one damage scenario because of the limited number of sensors. The two methods were first briefly reviewed. Next, using a 3D offshore platform model, the damage detection algorithms were implemented with different levels of damage severities for both single damage and multiple damage cases. Finally, a physical model of an offshore steel platform was constructed for modal testing and for validating the applicability. Results indicate that the MSED method outperforms the Stubbs index method for structural damage detection.

关键词： offshore platform damage localization strain energy mode shapes modal testing

damage localization of Long-span Spatial Lattice Structures

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Damage Localization of Long-span Spatial Lattice Structures

damage localization-a Precursor to Failure

中国钢结构协会结构稳定与疲劳分会2006年学术交流会暨钢结构教学研讨会

作者： DING Yang, ZHANG Jiwei, LI Zhongxian (School of Civil Engineering, Tianjin University, Tianjin, P.R.China, 300072)

In this paper, based on the mode curvature method and the artificial neural network technology, a new method for damage localization for long-span spatial lattice structures is introduced. Through the investigation and comparison, the parameters suitable for the damage localization of the long-span spatial lattice structures are determined, and the different damage cases for a long-span cantilever tubular truss structure of the stadium in Tianjin Olympic Sport Center are numerically simulated to verify the applicability and effectiveness of the established damage localization method.

关键词： long-span spatial structures lattice structure damage identification damage localization mode curvature artificial neural network (ANN)

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Damage Localization-a Precursor to Failure

Impact localization of composite laminates based on weight function compensation localization algorithm of thin film sensors

2007国际机械工程与力学会议

作者： Y.L.BAI X.H.XU M.F.XIA F.J.KE State Key Laboratory of Non-linear Mechanics (LNM) Institute of MechanicsChinese Academy of Sciences Department of Physics Peking University Department of Applied Physics Beihang University

This paper reviews the concept of damage localization and its application to time-independent （quasi-static） and time-dependent processes in heterogeneous materials. For quasi-static process in a heterogeneous material with Weibull distribution, damage can be expressed by a function of state variable. Accordingly, the criterion for damage localization depends on Weibull modulus m. In particular, damage localization can appear even though stress gradient remains fixed and it is closely related to strain localization. For time-dependent process, damage evolution law can be expressed by a function of stress and damage f （ σ , D ） . Accordingly, the criterion for damage localization can be expressed by f D ＞ f / D . Provided damage evolution law can be expressed by kinetics of microdamage, it is found that intrinsic Deborah number D * plays a key role in damage localization. The criterion for damage localization has been applied to two extremes of time-dependent processes: spallation under wave loading and creep.

关键词： damage localization heterogeneity intrinsic Deborah number

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International Journal of Smart and Nano Materials 2023年第2期14卷 139-154页

作者： Ying Wang Hongmei Li Shaowei Lu Xingmin Liu Wei Li Xiaoqiang Wang Lu Zhang Qingxuan Wang College of Aerospace Engineering Shenyang Aerospace University(SAU)ShenyangChina College of Material Science and Engineering Shenyang Aerospace University(SAU)ShenyangChina

Composite structures are sensitive to impact damage in practical *** resistance change method(ERCM)is an ideal technique for damage monitoring of composite *** to the anisotropy of fiber-resin matrix composites,impact location monitoring is difficult,and research on impact location of fiber composite laminates(FRPs)is limited.A preparation method of MXene/CNT/CuNps thin film sensor is *** to the modeling simulation and theoretical calculation,the resistance change characteristics of the thin film sensor are obtained,the relationship between the impact distance and the resistance change is established,and the sensor array is designed.A three-point localization algorithm and a weight function compensation localization algorithm are proposed,which can improve the imaging accuracy of the impact *** impact point location was observed and analyzed using ultrasonic C-scan *** results show that the weight function compensation positioning algorithm can accurately locate the impact of the composite structure,and the error in the X direction is 7.1%,the error in the Y direction is 0.03%,which verifies the effectiveness of the method.

关键词： Electric resistance change method Mxene/CNT/CuNps film sensor damage localization Weighting function

A dynamic stiffness-based framework for harmonic input estimation and response reconstruction considering damage

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Frontiers of Structural and Civil Engineering 2022年第4期16卷 448-460页

作者： Yixian LI Limin SUN Wang ZHU Wei ZHANG Department of Bridge Engineering College of Civil EngineeringTongji UniversityShanghai 200092China State Key Laboratory of Disaster Reduction in Civil Engineering Department of Bridge EngineeringCollege of Civil EngineeringTongji UniversityShanghai 200092China Shanghai Qizhi Institute Shanghai 200092China Sichuan Highway Planning SurveyDesignand Research Institute Ltd.Chengdu 610000China Fujian Key Laboratory of Green Building Technology Fujian Academy of Building ResearchFuzhou 350028China

In structural health monitoring(SHM),the measurement is point-wise but structures are ***,input estimation has become a hot research subject with which the full-field structural response can be calculated with a finite element model(FEM).This paper proposes a framework based on the dynamic stiffness theory,to estimate harmonic input,reconstruct responses,and to localize damages from seriously deficient *** begin,Fourier transform converts the dynamic equilibrium equation to an equivalent static one in the frequency domain,which is underdetermined since the dimension of measurement vector is far less than the FEM-node *** principal component analysis has been adopted to“compress”the under-determined equation,and formed an over-determined equation to estimate the unknown ***,inverse Fourier transform converts the estimated input in the frequency domain to the time *** this to the FEM can reconstruct the target *** a structure is damaged,the estimated nodal force can localize the *** improve the damage-detection accuracy,a multi-measurement-based indicator has been *** simulations have validated that the proposed framework can capably estimate input and reconstruct multi-types of full-field responses,and the damage indicator can localize minor damages even with the existence of noise.

关键词： dynamic stiffness principal component analysis response reconstruction damage localization underdetermined equation

Localizing structural damage based on auto-regressive with exogenous input model parameters and residuals using a support vector machine based learning approach

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Frontiers of Structural and Civil Engineering 2024年第10期18卷 1492-1506页

作者： Burcu GUNES Department of Civil Engineering Istanbul Technical UniversityIstanbul 34467Turkey

Machine learning algorithms operating in an unsupervised fashion has emerged as promising tools for detecting structural damage in an automated *** essence relies on selecting appropriate features to train the model using the reference data set collected from the healthy structure and employing the trained model to identify outlier conditions representing the damaged *** this paper,the coefficients and the residuals of the autoregressive model with exogenous input created using only the measured output signals are extracted as damage *** features obtained at the baseline state for each sensor cluster are then utilized to train the one class support vector machine,an unsupervised classifier generating a decision function using only patterns belonging to this baseline *** damage,once detected by the trained machine,a damage index based on comparison of the residuals between the trained class and the outlier state is implemented for localizing *** two-step damage assessment framework is first implemented on an eight degree-of-freedom numerical model with the effects of measurement noise ***,vibration data collected from a one-story one-bay reinforced concrete frame inflicted with progressive levels of damage have been utilized to verify the accuracy and robustness of the proposed methodology.

关键词： structural health monitoring damage localization auto-regressive with exogenous input models one-class support vector machine reinforced concrete frame

New Developments in Structural Health Monitoring Based on Diagnostic Lamb Wave

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Journal of Materials Science & Technology 2004年第5期20卷 490-496页

作者： Shenfang YUAN, Yingdi XU and Ge PENGThe Smart Materials & Structures Aeronautic Key Laboratory, Nanjing University of Aeronautic and Astronautic, Nanjing 210016, China Smart Mat. and Structures Aero. Lab. Nanjing Univ. of Aero. and Astron. Nanjing 210016 China

Structure health monitoring based on diagnostic Lamb waves has been found to be one of the most promising techniques recently. This paper has a brief review of the new developments on this method including the basic novel of the method, fundamentals and mathematics of Lamb wave propagation, narrowband and wideband Lamb wave excitation methods, optimization of excitation factors and diagnostic Lamb wave interpretation methods.

关键词： Structural health monitoring Lamb wave methods Factor optimization damage localization

SPALLATION ANALYSIS WITH A CLOSED TRANS-SCALE FORMULATION OF damage EVOLUTION

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Acta Mechanica Sinica 2004年第4期20卷 400-407页

作者：汪海英白以龙夏蒙棼柯孚久 LNM Institute of MechanicsChinese Academy of SciencesBeijing 100080China

A closed,trans-scale formulation of damage evolution based on the statistical mi- crodamage mechanics is summarized in this *** dynamic function of damage bridges the mesoscopic and macroscopic evolution of *** spallation in an aluminium plate is studied with this *** is found that the damage evolution is governed by several dimensionless parameters, i.e.,imposed Deborah numbers De~* and De,Mach number M and damage number *** particular, the most critical mode of the macroscopic damage evolution,i.e.,the damage localization,is deter- mined by Deborah number De~*.Deborah number De~* reflects the coupling and competition between the macroscopic loading and the microdamage ***,our results reveal the multi-scale nature of *** fact,the damage localization results from the nonlinearity of the microdamage *** addition,the dependence of the damage rate on imposed Deborah numbers De~* and De, Mach number M and damage number S is discussed.

关键词： spallation statistical microdamage mechanics damage evolution damage localization closed trans-scale formulation