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Identification of moving vehicle forces on bridge structures via moving average Tikhonov regularization

SMART MATERIALS AND STRUCTURES 2017年第8期26卷

作者： Pan, Chu-Dong Yu, Ling Liu, Huan-Lin Jinan Univ Sch Mech & Construct Engn Guangzhou 510632 Guangdong Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

Traffic-induced moving force identification (MFI) is a typical inverse problem in the field of bridge structural health monitoring. Lots of regularization-based methods have been proposed for MFI. However, the MFI accuracy obtained from the existing methods is low when the moving forces enter into and exit a bridge deck due to low sensitivity of structural responses to the forces at these zones. To overcome this shortcoming, a novel moving average Tikhonov regularization method is proposed for MFI by combining with the moving average concepts. Firstly, the bridge-vehicle interaction moving force is assumed as a discrete finite signal with stable average value (DFS-SAV). Secondly, the reasonable signal feature of DFS-SAV is quantified and introduced for improving the penalty function (||x||(2)(2)) defined in the classical Tikhonov regularization. Then, a feasible two-step strategy is proposed for selecting regularization parameter and balance coefficient defined in the improved penalty function. Finally, both numerical simulations on a simply-supported beam and laboratory experiments on a hollow tube beam are performed for assessing the accuracy and the feasibility of the proposed method. The illustrated results show that the moving forces can be accurately identified with a strong robustness. Some related issues, such as selection of moving window length, effect of different penalty functions, and effect of different car speeds, are discussed as well.

关键词： moving force identification (MFI) regularization method moving average structural health monitoring (SHM)

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Fracture failure analysis of Fiber Reinforced Composites T-joints 4

Fracture failure analysis of Fiber Reinforced Composites T-j...

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4th International Conference on Advanced Composite Materials and Manufacturing engineering (ACMME)

作者： Su, Wei Kong, De-zhi Liu, Ren-huai Huang, Shi-qing China Elect Prod Reliabil & Environm Testing Res Sci & Technol Reliabil Phys & Applicat Technol El Guangzhou Guangdong Peoples R China Jinan Univ Dept Mech & Civil Engn Guangzhou Guangdong Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou Guangdong Peoples R China

This paper discusses staple FRP T-joints on the project based on the classical beam theory of Euler-Bernoulli and a theoretical model of energy release rate is set up to discuss fracture propagation of composite T-joints. The paper is further analysis on fracture failure affected by composite pane depth and joints chamfer dimension parameters and so on. The conclusion benefit for extensive use of projects is also summarized.

关键词： Fiber reinforced plastics

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Mechanical Deformation Mechanism of Fiber Reinforced Composites T-joints 4

Mechanical Deformation Mechanism of Fiber Reinforced Composi...

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4th International Conference on Advanced Composite Materials and Manufacturing engineering (ACMME)

作者： Su, Wei Cheng, Ke-qiang Liu, Ren-huai Huang, Shi-qing China Elect Prod Reliabil & Environm Testing Res Sci & Technol Reliabil Phys & Applicat Technol El Guangzhou Guangdong Peoples R China Jinan Univ Dept Mech & Civil Engn Guangzhou Guangdong Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou Guangdong Peoples R China

In this paper, we focus on the need for ideal theory analytical solution of mechanical deformation mechanism for T-joints. Through removing unnecessary constraints, stress equivalence system of T-joints can be established by force method. Solution equations of unknown nodal forces and the total vertical displacement can also be obtained, and this result can be used to evaluate strength of FRC T-joints.

关键词： Deformation

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Heat and mortality for ischemic and hemorrhagic stroke in 12 cities of Jiangsu Province, China

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SCIENCE OF THE TOTAL ENVIRONMENT 2017年 601卷 271-277页

作者： Zhou, Lian Chen, Kai Chen, Xiaodong Jing, Yuanshu Ma, Zongwei Bi, Jun Kinney, Patrick L. Nanjing Univ Informat Sci & Technol Coll Appl Meteorol 219 Ningliu Rd Nanjing 210044 Jiangsu Peoples R China Jiangsu Prov Ctr Dis Prevent & Control Nanjing Jiangsu Peoples R China Nanjing Univ Sch Environm State Key Lab Pollut Control & Resource Reuse Nanjing Jiangsu Peoples R China Minist Educ Key Lab Meteorol Disaster Collaborat Innovat Ctr Forecast & Evaluat Meteoro Nanjing Jiangsu Peoples R China Jiangsu Collaborat Innovat Ctr Atmospher Environm Nanjing Jiangsu Peoples R China Boston Univ Sch Publ Hlth Dept Environm Hlth 715 Albany St Boston MA 02118 USA

Background: Little evidence exists on the relationship between heat and subtypes of stroke mortality, especially in China. Moreover, few studies have reported the effect modification by individual characteristics on heatrelated stroke mortality. In this study, we aimed to evaluate the effect of heat exposure on total, ischemic, and hemorrhagic stroke mortality and its individual modifiers in 12 cities in Jiangsu Province, China during 2009 to 2013. Methods: We first used a distributed lag non-linear model with quasi-Poisson regression to examine the cityspecific heat-related total, ischemic, and hemorrhagic stroke mortality risks at 99th percentile vs. 75th percentile of daily mean temperature in the whole year for each city, while adjusting for long-term trend, season, relative humidity, and day of the week. Then, we used a random-effects meta-analysis to pool the city-specific risk estimates. We also considered confounding by air pollution and effect modification by gender, age, education level, and death location. Results: Overall, the heat-relatedmortality risk in 12 Jiangsu cities was 1.54 (95% CI: 1.44 to 1.65) for total stroke, 1.63 (95% CI: 1.48 to 1.80) for ischemic stroke, and 1.36 (95% CI: 1.26 to 1.48) for hemorrhagic stroke, respectively. Estimated total, ischemic, and hemorrhagic strokemortality riskswere higher forwomen versus men, older people versus younger people, those with low education levels versus high education levels, and deaths that occurred outside of hospital. Air pollutants did not significantly influence the heat-related stroke mortality risk. Conclusions: Heat exposure significantly increased both ischemic and hemorrhagic strokemortality risks in Jiangsu Province, China. Females, the elderly, and those with low education levels are particularly vulnerable to this effect. (C) 2017 Elsevier B.V. All rights reserved.

关键词： Heat Ischemic stroke Hemorrhagic stroke Mortality Vulnerability

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LQD-RKHS-based distribution-to-distribution regression methodology for restoring the probability distributions of missing SHM data

arXiv

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arXiv 2018年

作者： Chen, Zhicheng Bao, Yuequan Li, Hui Spencer, Billie F. Key Lab of Intelligent Disaster Mitigation of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin China Key Lab of Structures Dynamic Behaviour and Control of the Ministry of Education Harbin Institute of Technology Harbin China School of Civil Engineering Harbin Institute of Technology Harbin China Department of Civil and Environmental Engineering University of Illinois at Urbana-Champaign UrbanaIL United States Department of Civil and Environmental Engineering University of Illinois at Urbana - Champaign UrbanaIL United States

Data loss is a critical problem in structural health monitoring (SHM). Probability distributions play a highly important role in many applications. Improving the quality of distribution estimations made using incomplete samples is highly important. Missing samples can be compensated for by applying conventional missing data restoration methods;however, ensuring that restored samples roughly follow underlying distributions of true missing data remains a challenge. Another strategy involves directly restoring the probability density function (PDF) for a sensor when samples are missing by leveraging distribution information from another sensor with complete data using distribution regression techniques;existing methods include the conventional distribution-to-distribution regression (DDR) and distribution-to-warping function regression (DWR) methods. Due to constraints on PDFs and warping functions, the regression functions of both methods are estimated from the Nadaraya-Watson kernel estimator with relatively low degrees of precision. This article proposes a new indirect distribution-to-distribution regression method in the context of functional data analysis for restoring distributions of missing SHM data. PDFs are transformed to ordinary functions residing in a Hilbert space via the newly proposed log-quantile-density (LQD) transformation;the regression for distributions is realized in the transformed space via a functional regression model constructed based on the theory of Reproducing Kernel Hilbert Space (RKHS), corresponding result is subsequently mapped back to the density space through the inverse LQD transformation. Test results using field monitoring data indicate that the new method significantly outperforms conventional methods in general cases;however, in extrapolation cases, the new method is inferior to the distribution-to-warping function regression method. Copyright © 2018, The Authors. All rights reserved.

关键词： Probability distributions

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Mechanism and control of spalling for friable sandstone pillars in a room and pillar mine

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Journal of engineering Science and Technology Review 2018年第6期11卷 197-205页

作者： Ziwei, Ding Jindui, Jia Amirhossein, Bagherieh Ji, Li Yue, Song School of Energy Xi'an University of Science and Technology Xi'an710054 China Anhui Province Key Lab. of Mining Response and Disaster Prevention Control in Deep Coal Mine Anhui University of Science and Technology Huainan232001 China Department of Mineral engineering New Mexico Institute of Mining and Technology SocorroNM87801 United States

The ability to efficiently control sandstone pillar spalling is extremely important in ensuring the safety and highefficiency production of sandstone mines. The increase in size is usually suggested as a remedy for pillar spalling, but none of the suggested remedies reflect the influences of geotechnical properties of rock mass on stability control. Some sandstone mining practices have proven that increasing the size of pillars cannot effectively control pillar spalling. The relationship between the strength of St. Peter sandstone pillar and pillar loads was theoretically analyzed in the current study, in order to examine the influences of geotechnical parameters of sandstone on the stability of pillars and control pillar spalling. The key geotechnical parameters that influence the stability of sandstone pillars were also examined. Subsequently, the pillar instability mechanism and influences of geotechnical parameters on pillar stability were investigated by Finite Difference Method. Finally, a ground control method using shotcrete on pillar was proposed for increasing the stability of pillars. Results demonstrate that compressive stress on the St. Peter sandstone pillar is considerably larger than the compressive strength after mining, resulting in the evident deformation of most regions. The relation curves of displacement at the pillar top with internal friction angle and cohesion are in the power functional distributions, but the change of cohesion is more significant in the pillar strength. The displacement at the pillar top gradually decreases with the increase in internal friction angle, whereas the plastic failure regions of pillars gradually decrease from the bottom to the upper parts with the increase in cohesion. A field industrial test proves that shotcrete on pillars can increase pillar strength, which effectively controls the pillar spalling. Research results provide theoretical and practical guidelines to enhance the stability of pillars under the sa

关键词： Rock mechanics

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A Simulation of Low and High Cycle Fatigue Failure Effects for Metal Matrix Composites Based on Innovative J₂-Flow Elastoplasticity Model

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MATERIALS 2017年第10期10卷 1126页

作者： Wang, Zhaoling Xiao, Heng Weifang Univ Sch Math & Informat Sci Weifang 261061 Peoples R China Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

New elastoplastic J(2)-flow constitutive equations at finite deformations are proposed for the purpose of simulating the fatigue failure behavior for metal matrix composites. A new, direct approach is established in a two-fold sense of unification. Namely, both low and high cycle fatigue failure effects of metal matrix composites may be simultaneously simulated for various cases of the weight percentage of reinforcing particles. Novel results are presented in four respects. First, both the yield condition and the loading-unloading conditions in a usual sense need not be involved but may be automatically incorporated into inherent features of the proposed constitutive equations;second, low-to-high cycle fatigue failure effects may be directly represented by a simple condition for asymptotic loss of the material strength, without involving any additional damage-like variables;third, both high and low cycle fatigue failure effects need not be separately treated but may be automatically derived as model predictions with a unified criterion for critical failure states, without assuming any ad hoc failure criteria;and, finally, explicit expressions for each incorporated model parameter changing with the weight percentage of reinforcing particles may be obtainable directly from appropriate test data. Numerical examples are presented for medium-to-high cycle fatigue failure effects and for complicated duplex effects from low to high cycle fatigue failure effects. Simulation results are in good agreement with experimental data.

关键词： metal matrix composites high and low cycle fatigue finite deformations new elastoplastic equations unified failure criterion direct simulation

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Data science and engineering for structural health monitoring 8

Data science and engineering for structural health monitorin...

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8th International Conference on Structural Health Monitoring of Intelligent Infrastructure, SHMII 2017

作者： Li, H. Bao, Y.Q. Li, S.L. Ou, J.P. Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin150090 China Key Lab of Intelligent Disaster Mitigation of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China

ISBN: (纸本)9781925553055

Structural health monitoring (SHM) technology study the damage or even characteristics of disaster evolving of structures by various types of sensors installed on structures and provide scientific support for the structural design, construction, maintenance and operation safety. The significant scientific issues of SHM can be concluded as 'sensing' and 'data'. According to the widely application of SHM on civil infrastructures and accumulation of huge quantities of data, it is well-recognized that data sciences and engineering for SHM is increasingly becoming a world-wide research focus. The issue of 'data' is core target of SHM which includes the data acquisition, transmission and management, data analysis and mining, structural damage identification and structural safety assessment and so on. This paper reviews the recent research development of data sciences and engineering on our research group which includes data acquisition by compressive sensing based on group sparse optimization, computer vison and deep learning methods for data anomaly detection and structure condition assessment, the identification and modeling of spatio-temporal distribution of vehicle loads, and corrosion damage and crack identification by computer vision ***, the artificial intelligence in civil engineering is the extension of SHM technique, and will make the civil structure have ability of "see", "sensing", "thinking","talking", "action and "adapation" (2S+2T+2A). © 2017 International Society for Structural Health Monitoring of Intelligent Infrastrucure. All rights reserved.

关键词： Structural health monitoring

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An on-site evaluation method for corrosion degradation of in-service cable wires by image histogram matching 11

An on-site evaluation method for corrosion degradation of in...

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11th International Workshop on Structural Health Monitoring 2017: Real-Time Material State Awareness and Data-Driven Safety Assurance, IWSHM 2017

作者： Xu, Yang Li, Shunlong Li, Hui Gu, Chenyu Li, Xinbin Chen, Xiaowei Qiao, Weidong Key Lab of Intelligent Disaster Mitigation Ministry of Industrial and Information Technology Harbin150090 China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters Ministry of Industry and Information Technology Harbin150090 China Key Lab of Structures Dynamic Behavior and Control Ministry of Education Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China School of Transportation Science and Engineering Harbin Institute of Technology Harbin150090 China

ISBN: (纸本)9781605953304

This paper proposes a novel non-destructive method by image histogram matching to evaluate the corrosion degradation of cable wires in service quantitatively. Artificial accelerated salt spray test is adopted to simulate the corrosion environment, and adequate RGB images are taken by a consumer-grade camera to cover the whole information of corroded surface for each specimen under different corrosion periods. Histogram distribution analysis is applied to study the concentrated modes of RGB images, and joint Gaussian distribution is fitted to capture location parameters. Timevariant models of the location parameters are regressed and then the mechanical properties are learnt by tensile and fatigue tests. Once the features of RGB corrosion images of steel wires are matched to the proposed time-variant models, the corresponding corrosion degree and mechanical properties can be estimated. The proposed method is meaningful for the on-site evaluation of cable wires in service with no need to carry on corrosion and mechanical degradation tests after replacing cables.

关键词： Graphic methods

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R-function theory method for free vibration of slip clamped trapezoidal shallow spherical shell 4th

R-function theory method for free vibration of slip clamped ...

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4th International Conference on Civil, Architectural and Hydraulic engineering, ICCAHE 2015

作者： Li, Shanqing Yuan, Hong MOE Key Laboratory of Disaster Forecast and Control in Engineering Institute of Applied Mechanics Jinan University Guangzhou China

ISBN: (纸本)9781138029163

In this paper, the R-Function Theory (RFT) is applied to solve the free vibration of slip clamped trapezoidal shallow spherical shell. Firstly the fundamental solution of the biharmonic operator, the boundary equation and the R-function are used to construct the quasi-Green’s function. Then the model governing differential equation of the problem is reduced to the Fredholm integral equation of the second kind by Green’s formula. The singularity of the kernel of the integral equation is overcome by choosing a suitable form of the normalized boundary equation by the R-function. A numerical example shows that this method is an effective numerical method. © 2016 Taylor & Francis Group, London.

关键词： Numerical methods

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