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Structural damage detection based on modal strain energy assurance criterion using adaptive region shrinkage assisted IGOA

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STRUCTURES 2023年 58卷

作者： Chen, Zepeng Liu, Qitian Pan, Chudong Foshan Univ Sch Transportat & Civil Engn & Architecture Foshan Peoples R China Guangzhou Univ Sch Civil Engn Guangzhou Peoples R China Jinan Univ KOE Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China

The efficiency in high-dimension optimization, premature convergence and noise robustness are common challenges that restrict the application of swarm-based algorithms in structural damage detection (SDD). In order to overcome these limitations, an improved grasshopper optimization algorithm (IGOA) based SDD approach assisted with adaptive region shrinkage strategies is proposed using modal strain energy assurance criterion. Firstly, the effectiveness of GOA in handling SDD is investigated, and an improved version is subsequently introduced with two adaptive region shrinkage strategies: adaptive Le ' vy flight mechanism and elite oppositionbased learning, aiming to achieve more accurate and stable SDD results. Additionally, a novel objective function is defined, combining the frequency change ratio (FCR) and modal strain energy assurance criterion (MSEAC). To assess the performance of the proposed algorithm, a comparative analysis is conducted with four other selected swarm intelligent algorithms and GOAs with individual modification using four CEC benchmark functions. The results demonstrate that the proposed algorithm achieves improved convergence rate and accuracy. Furthermore, the effectiveness and efficiency of the proposed algorithm in SDD are validated through two numerical simulations and an experimental test. The SDD results obtained from both numerical simulations and experimental tests confirm the accuracy and robustness of the proposed method.

关键词： Structural damage detection (SDD) Improved grasshopper optimization algorithm (IGOA) Modal strain energy assurance criterion (MSEAC) Adaptive Le ' vy flight Elite opposition-based learning

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Mechanical behaviour of bonded joints including viscoelasticity for the adhesive under triangular pulse loading and harmonic loading

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COMPOSITE STRUCTURES 2021年 272卷 114220-114220页

作者： Wu, Jiayu Southern Univ Sci & Technol Dept Ocean Sci & Engn Shenzhen 518055 Peoples R China Southeast Univ Sch Civil Engn Nanjing 210096 Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

The constitutive law of the interface is a prime issue when evaluating the strength of adhesively bonded joints. The polymer-based adhesives exhibit loading rate sensitivity and damping properties owing to their viscous nature, especially at high temperatures or under water. This paper aims to establish a shear-lag model to elucidate the mechanical behaviour of adhesively bonded joints under triangular pulse loading and harmonic loading. The extended shear-lag model is focused on improving the previous shear-lag models by including viscoelastic behaviour using the Kelvin model for the adhesive. Analytical expressions of the slip and interfacial shear stress distribution have been respectively presented for pull-push joint and pull-pull joint under triangular pulse loading. Compared with finite element simulation, the predictive model shows an excellent agreement with the FEA results. The damping properties including the storage modulus, loss modulus and loss factor for these two bonded joints subjected to harmonic loading are theoretically derived. Finally, results obtained from the predictive model are presented to illustrate how the bond length, loading rate and loading frequency affect the behaviour of such bonded joints.

关键词： Adhesively bonded joint Shear-lag model Interfacial stress transfer Triangular pulse loading Harmonic loading Analytical solution

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New finite strain elastoplastic equations for accurately and explicitly simulating pseudoelastic-to-plastic transition effects of shape memory alloys

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Applied Mathematics and Mechanics(English Edition) 2020年第10期41卷 1583-1596页

作者： Siyu WANG Lin ZHAN Huifeng XI Heng XIAO School of Mechanics and Construction Engineering MOE Key Lab of Disaster Forecast and Control in EngineeringJinan University601 West Huangpu AvenueGuangzhou 510632China Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy EngineeringSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China

A new finite strain elatoplastic J2-flow model with coupling effects of both isotropic and anisotropic hardening is proposed with the co-rotational logarithmic *** terms of certain single-variable shape functions representing uniaxial loading and unloading curves,explicit multi-axial expressions for the three hardening quantities incorporated in the new model proposed are derived in unified forms for the purpose of automatically and accurately simulating complex pseudoelastic-to-plastic transition effects of shape memory alloys(SMAs)under multiple loading-unloading *** examples show that with only a single parameter of direct physical meaning for each cycle,accurate and explicit simulations may be achieved for extensive data from multiple cycle tests.

关键词： shape memory alloy(SMA) finite deformation pseudo-elasticity plasticity cyclic loading transition effect elastoplastic equation explicit and accurate approach

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Impact Damage Analysis of Fiber Reinforced Plastic Structure with Rib

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ADVANCES IN MATERIALS SCIENCE AND engineering 2022年第0期2022卷

作者： Xiong Linghua Ming Zhimao Zhao Kelun Wang Fan Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Guangzhou GRG Metrol & Test Co Ltd Guangzhou 511458 Peoples R China

Fiber reinforced plastic (FRP) is a widely used structural form in engineering. FRP ribs can absorb most of the impact energy to protect the structure from damage. The purpose of this study is to obtain the impact resistance of FRP ribs by test and simulation. Taking glass fiber reinforced plastic (GFRP) oil sump as the object, the damage degree of structure under different impact angles, impact velocity, and impactor masses is compared and analyzed by material test, impact test, and simulation. It can be seen from the test results that the design of surface ribs has a great influence on the energy absorption effect of the shell. The constitutive parameters of the shell material are obtained by testing, and the failure mode of the ribs is analyzed by finite element simulation. The impact effects of flying stones with different incident angles, velocities, kinetic energy, and geometric dimensions on the shell are compared and analyzed. The results show that, at the same impact energy, the impact resistance characteristics change regularly under different working conditions. Under a certain incident angle, the damage effect caused by flying stones in a specific mass range is greater. Beyond a certain incident angle, the damage begins to occur, and the larger the incident angle is, the greater the damage effect is. Combined with the actual situation and road standards, the defense of medium quality flying stones is a major concern in the design of oil pan. The results are helpful for designing reasonable ribs to improve the reliability of FRP structures.

关键词： Kinetics

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Application of Honeycomb Structures in key Components of Space Deployable Structures

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ADVANCES IN MATERIALS SCIENCE AND engineering 2022年第1期2022卷

作者： Yang, Yang Wang, Fan Liu, Jieshan Jinan Univ Sch Mech & Construct Engn Guangzhou 510632 Peoples R China Minist Educ Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

The reed structure is the key component in the foldable space deployment mechanism. In the aerospace industry, weight loss occupies a pivotal position. The use of lightweight structure can achieve significant savings in launch costs and improve load efficiency. Aiming at the lightweight requirements of the space deployment mechanism, this paper discusses the substitution effect of the honeycomb topology on the reed structure in the space deployment structure. Firstly, the column structure of the honeycomb is equivalent to an orthotropic cylindrical block-shell structure. According to the bending theory of an orthotropic cylinder, the expanded honeycomb structure equivalent to an orthotropic cylindrical block-shell structure is deduced. Then, the exact expression of the reverse bending moment was obtained, and the bending moment-curvature curve during the folding process was drawn. The bending moment-curvature characteristics during the folding process are simulated by finite element numerical simulation. By proposing the index of unit mass for analysis and comparison, the results show that compared with the common spring steel structure, the honeycomb structure has better mechanical properties per unit mass and has a certain substitution effect on the reed structure.

关键词： Honeycomb Honeycomb structure

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Interface-rich Au-doped PdBi alloy nanochains as multifunctional oxygen reduction catalysts boost the power density and durability of a direct methanol fuel cell device

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Nano Research 2022年第7期15卷 6036-6044页

作者： Xin Li Ke Xin Yao Fengling Zhao Xiaotong Yang Jingwei Li Yongfei Li Qiang Yuan State-Local Joint Laboratory for Comprehensive Utilization of Biomass Center for R&D of Fine ChemicalsCollege of Chemistry and Chemical EngineeringGuizhou UniversityGuiyang 550025China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400044China Key Lab of Organic Optoelectronics&Molecular Engineering Tsinghua UniversityBeijing 100084China Multi-scale Porous Materials Center Institute of Advanced Interdisciplinary Studies&School of Chemistry and Chemical EngineeringChongqing UniversityChongqing 400044China

The development of cathode oxygen reduction reaction(ORR)catalysts with high characteristics for practical,direct methanol fuel cells(DMFCs)has continuously increased the attention of *** this work,interface-rich Au-doped PdBi(PdBiAu)branched one-dimensional(1D)alloyed nanochains assembled by sub-6.5 nm particles have been prepared,exhibiting an ORR mass activity(MA)of 6.40 A·mgPd^(−1) and long-term durability of 5,000 cycles in an alkaline *** MA of PdBiAu nanochains is 46 times and 80 times higher than that of commercial Pt/C(0.14 A·mgPt^(−1))and Pd/C(0.08 A·mgPd^(−1)).The MA of binary PdBi nanochains also reaches 5.71 A·mgPd^(−1).Notably,the PdBiAu nanochains exhibit high in-situ carbon monoxide poisoning resistance and high methanol *** actual DMFC device tests,the PdBiAu nanochains enhance power density of 140.1 mW·cm^(−2)(in O_(2))/112.4 mW·cm^(−2)(in air)and durability compared with PdBi nanochains and Pt/*** analysis of the structure–function relationship indicates that the enhanced performance of PdBiAu nanochains is attributed to integrated functions of surficial defect-rich 1D chain structure,improved charge transfer capability,downshift of the d-band center of Pd,as well as the synergistic effect derived from“Pd-Bi”and/or“Pd-Au”dual active sites.

关键词： Au-doped PdBi(PdBiAu)nanochains one-dimensional structure active auxiliary oxygen reduction reaction direct methanol fuel cells

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Dynamics-based cross-domain structural damage detection through deep transfer learning

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COMPUTER-AIDED CIVIL AND INFRASTRUCTURE engineering 2022年第1期37卷 24-54页

作者： Lin, Yi-zhou Nie, Zhen-hua Ma, Hong-wei Dongguan Univ Technol Sch Environm & Civil Engn Dongguan Peoples R China Jinan Univ Sch Mech & Construct Engn Guangzhou Peoples R China Minist Educ Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China Qinghai Univ Dept Civil Engn Xining Peoples R China 601 Huangpu Rd West Guangzhou Guangdong Peoples R China 1 Daxue Rd Dongguan Guangdong Peoples R China

Structural damage detection (SDD) still suffers from environmental uncertainties or modeling errors, causing a gap between the numerical model and the real structure. It results in performance degradation in the application of many model-based methods, which are usually designed on a numerical model and needed to be applied to a real structure. Such a situation is defined as a cross-domain SDD problem in this work. This paper aims to address the cross-domain SDD problem by designing a feature-extractor to generate both damage-sensitive and domain-invariant features, instead of trying to reduce the gap, as the traditional methods do. A domain adaptation (DA) neural network is designed and trained on the data from both the numerical model and the real structure at the same time. In addition, no damage label of the real structure is needed. Both numerical and laboratory experiments show that the proposed method has excellent performance and outperforms the baseline model, a traditional convolutional neural network (CNN). This paper provides a new methodology to solve the cross-domain SDD problem, that is, to learn better features instead of just trying to reduce the gap.

关键词： Numerical models

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Detection and Attribution of Changes in Thermal Discomfort over China during 1961-2014 and Future Projections

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Advances in Atmospheric Sciences 2022年第3期39卷 456-470,543-552页

作者： Wanling LI Xin HAO Li WANG Yuqing LI Jiandong LI Huixin LI Tingting HAN Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster Ministry of EducationNanjing University of Information Science and TechnologyNanjing 210044China Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science&TechnologyNanjing 210044China

In this study, variation in the frequency of thermal discomfort days over China during the period of 1961-2014,including heat discomfort days(HDDs) and cold discomfort days(CDDs), and the influence of external forcings on it are discussed. HDDs are the conditions of overheating and overhumidity(represented by humidity index), and CDDs reflect the dangers from cold temperatures and winds(represented by wind chill index). Observations show significant increases(decreases) in the frequency of HDDs(CDDs) over China from 1961 to 2014, with clear regional distinctions. The historical ALL and greenhouse gas(GHG) simulations can sufficiently reproduce the spatial patterns of the observational trend in the frequency of both HDDs and CDDs over China. Further, the impacts of GHG and anthropogenic forcings on the HDDs(CDDs) are detectable over China, except for central and eastern China, based on the optimal fingerprinting method. GHG forcing is identified as a dominant factor for the observational changes in the frequency of HDDs over southern China;GHG and anthropogenic forcings have dominant effects on the variation in the frequency of CDDs over southwestern China. Although trends in the frequency of HDDs and CDDs in historical aerosol forcing simulations seems to be opposite to observations, an aerosol signal fails to be detected. Natural forcing contributes to the observational variation in the frequency of HDDs over northwestern China. In addition, the future projections of thermal discomfort days indicate that Chinese residents will face more threats of heat discomfort and fewer threats of cold discomfort in the future under global warming.

关键词： thermal discomfort greenhouse gas anthropogenic influence natural forcing aerosol forcing

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Transverse Free Vibration of Axisymmetric Functionally Graded Circular Nanoplates with Radial Loads

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JOURNAL OF VIBRATION engineering & TECHNOLOGIES 2021年第6期9卷 1253-1268页

作者： Luo, Qiuyang Li, Cheng Li, Shuang Soochow Univ Sch Rail Transportat Dept Vehicle Engn Suzhou 215131 Jiangsu Peoples R China Guilin Univ Elect Technol Guangxi Key Lab Cryptog & Informat Secur Guilin 541004 Guangxi Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

Purpose The functionally graded circular nanoplate is a commonly seen component in the nano-electromechanical system. It is indispensable to examine free vibration behaviors of such an axisymmetric nanostructure subjected to uniformly distributed loads in the radial direction. Although the vibration engineering and technology have been fully studied at the macro-scale, there are still many unsolved problems at the micro-scale. The present research aims to promote the theoretical characterization of vibration behaviors at micro/nano-scale and further provide a basis for the development of vibration testing technologies. Methods Using the nonlocal strain gradient approach and Mindlin plate theory, we develop the theoretical model describing the transverse free vibration of the axisymmetric functionally graded circular nanoplate. First, by considering the nonlocal strain gradient constitutive relation, we derive the equation of motion via Hamilton's principle in polar coordinate system. Subsequently, the differential quadrature method is employed to solve the equation of motion numerically. Results The natural frequencies of circular nanoplates decrease with an increase of a radial compression while increase with an increase of a radial tension. The first-mode natural frequency reduces to zero under a certain radial compression, bringing about the dynamical instability. The natural frequencies are sensitive to the radial compression, and the clamped boundary constraint is more resistant to external loads than the simply supported one. An increase in the nonlocal parameter results in lower natural frequencies, while an increase in the strain gradient characteristic parameter results in higher ones. Conclusions It is demonstrated that the strain gradient characteristic parameter has a threshold in the present model for functionally graded circular nanoplates. In the circumstance of a lower nonlocal parameter than the strain gradient characteristic parameter, the circular

关键词： Nonlocal strain gradient Functionally graded Axisymmetric Circular nanoplate Vibration

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Damage localization of bridge based on moving sensing-filtering integrated system 10

Damage localization of bridge based on moving sensing-filter...

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10th International Conference on Bridge Maintenance, Safety and Management (IABMAS)

作者： Nie, Z. H. Xie, Y. K. Shen, Z. F. Ma, H. W. Jinan Univ Coll Sci & Engn Guangzhou Guangdong Peoples R China Key Lab Disaster Forecast & Control Engn Guangzhou Guangdong Peoples R China Dongguan Univ Technol Dongguan Peoples R China

ISBN: (纸本)9780429279119;9780367232788

In this paper, a novel damage detection method for beam bridge based on moving sensingfiltering integrated system is proposed. In this method, the single moving sensor is used to measure the acceleration signal of the moving vehicle, and a moving filter function with a fixed window length is used to scan the measured signal to locate the damage. The performance of the method in the numerical simulation on a simply supported beam demonstrates the proposed method is a good candidate in damage localization. This method uses only a single sensor and it is a baseline free data-driven method, which is very important in practical application of structures.

关键词： Numerical methods

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