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Multi-damage identification based on joint approximate diagonalisation and robust distance measure

Journal of Physics: Conference Series 2017年第1期842卷

作者： S Cao H Ouyang Centre for Engineering Dynamics School of Engineering The University of Liverpool Liverpool L69 3GH U.K. State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116023 China

Mode shapes or operational deflection shapes are highly sensitive to damage and can be used for multi-damage identification. Nevertheless, one drawback of this kind of methods is that the extracted spatial shape features tend to be compromised by noise, which degrades their damage identification accuracy, especially for incipient damage. To overcome this, joint approximate diagonalisation (JAD) also known as simultaneous diagonalisation is investigated to estimate mode shapes (MS's) statistically. The major advantage of JAD method is that it efficiently provides the common Eigen-structure of a set of power spectral density matrices. In this paper, a new criterion in terms of coefficient of variation (CV) is utilised to numerically demonstrate the better noise robustness and accuracy of JAD method over traditional frequency domain decomposition method (FDD). Another original contribution is that a new robust damage index (DI) is proposed, which is comprised of local MS distortions of several modes weighted by their associated vibration participation factors. The advantage of doing this is to include fair contributions from changes of all modes concerned. Moreover, the proposed DI provides a measure of damage-induced changes in 'modal vibration energy' in terms of the selected mode shapes. Finally, an experimental study is presented to verify the efficiency and noise robustness of JAD method and the proposed DI. The results show that the proposed DI is effective and robust under random vibration situations, which indicates that it has the potential to be applied to practical engineering structures with ambient excitations.

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Real-time hybrid simulation of single and multiple tuned liquid column dampers for controlling seismic-induced response 6

Real-time hybrid simulation of single and multiple tuned liq...

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Joint 6th International Conference on Advances in Experimental structural engineering, AESE 2015 and 11th International Workshop on Advanced Smart Materials and Smart Structures Technology, ANCRiSST 2015

作者： Zhu, Fei Wang, Jin-Ting Prof, Feng Jin Altay, Okyay State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing100084 China State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing100084 China State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing100084 China Department of Structural Analysis and Dynamics RWTH Aachen University Aachen52074 Germany

Tuned liquid column damper (TLCD) is a special type of tuned liquid damper to dissipate energy of structures subjected to dynamic loads. Due to its geometric flexibility and low prime costs, TLCD is a good alternative over other damping measurements for slender structures. In this paper, the real-time hybrid simulation (RTHS) technique is employed to investigate the dynamic behavior of structures with TLCDs attached, which intend to simultaneously suppressing single and multiple modal responses. First, the verification of RTHS is demonstrated by means of a single TLCD controlling a single degree-of-freedom shear frame, and variations of structural parameters are also considered to study their effects on control efficiency. Then, the dynamic response of a 9-story benchmark building under the control of single and multiple TLCDs is further investigated. Reduction efficiencies of TLCDs are evaluated by comparing the results with those without TLCD. Results show that TLCD could play excellent performance to control seismic-induced responses. © International Conference on Advances in Experimental structural engineering. All rights reserved.

关键词： Dynamic loads

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Effect of climate on traits of dominant and rare tree species in the world's forests

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Nature communications 2025年第1期16卷 4773页

作者： Iris Hordijk Lourens Poorter Jingjing Liang Peter B Reich Sergio de-Miguel Gert-Jan Nabuurs Javier G P Gamarra Han Y H Chen Mo Zhou Susan K Wiser Hans Pretzsch Alain Paquette Nicolas Picard Bruno Hérault Jean-Francois Bastin Giorgio Alberti Meinrad Abegg Yves C Adou Yao Angelica M Almeyda Zambrano Braulio V Alvarado Esteban Alvarez-Davila Patricia Alvarez-Loayza Luciana F Alves Iêda Amaral Christian Ammer Clara Antón-Fernández Alejandro Araujo-Murakami Luzmila Arroyo Valerio Avitabile Gerardo A Aymard C Timothy Baker Olaf Banki Jorcely Barroso Meredith L Bastian Luca Birigazzi Philippe Birnbaum Robert Bitariho Pascal Boeckx Frans Bongers Olivier Bouriaud Pedro H S Brancalion Susanne Brandl Francis Q Brearley Roel Brienen Eben N Broadbent Helge Bruelheide Roberto Cazzolla Gatti Ricardo G Cesar Goran Cesljar Robin L Chazdon Chelsea Chisholm Emil Cienciala Connie J Clark David B Clark Gabriel Colletta David Coomes Fernando Cornejo Valverde Jose J Corral-Rivas Philip Crim Jonathan Cumming Selvadurai Dayanandan André L de Gasper Mathieu Decuyper Géraldine Derroire Ben DeVries Ilija Djordjevic Aurélie Dourdain Jiri Dolezal Nestor Laurier Engone Obiang Brian Enquist Teresa Eyre Adandé Belarmain Fandohan Tom M Fayle Leandro V Ferreira Ted R Feldpausch Leena Finér Markus Fischer Christine Fletcher Lorenzo Frizzera Damiano Gianelle Henry B Glick David Harris Andrew Hector Andreas Hemp John Herbohn Annika Hillers Eurídice N Honorio Coronado Cang Hui Hyunkook Cho Thomas Ibanez Ilbin Jung Nobuo Imai Andrzej M Jagodzinski Bogdan Jaroszewicz Vivian Johannsen Carlos A Joly Tommaso Jucker Viktor Karminov Kuswata Kartawinata Elizabeth Kearsley David Kenfack Deborah Kennard Sebastian Kepfer-Rojas Gunnar Keppel Mohammed Latif Khan Timothy Killeen Hyun Seok Kim Kanehiro Kitayama Michael Köhl Henn Korjus Florian Kraxner Diana Laarmann Mait Lang Simon Lewis Huicui Lu Natalia Lukina Brian Maitner Yadvinder Malhi Eric Marcon Beatriz Schwantes Marimon Ben Hur Marimon-Junior Andrew Robert Marshall Emanuel Martin Olga Martynenko Jorge A Mea Institute of Integrative Biology ETH Zurich (Swiss Federal Institute of Technology) Zurich Switzerland. irishordijk@***. Wageningen University and Research Wageningen The Netherlands. irishordijk@***. Wageningen University and Research Wageningen The Netherlands. Department of Forestry and Natural Resources Purdue University West Lafayette IN USA. Department of Forest Resources University of Minnesota St Paul MN USA. Hawkesbury Institute for the Environment Western Sydney University Penrith NSW Australia. Department of Agricultural and Forest Sciences and Engineering University of Lleida Lleida Spain. Forest Science and Technology Centre of Catalonia (CTFC) Solsona Spain. Forestry Division Food and Agriculture Organization of the United Nations Rome Italy. Faculty of Natural Resources Management Lakehead University Thunder Bay ON Canada. Manaaki Whenua-Landcare Research Lincoln New Zealand. Chair for Forest Growth and Yield Science TUM School for Life Sciences Technical University of Munich Munich Germany. Centre for Forest Research Université du Québec à Montréal Montréal QC Canada. GIP ECOFOR Paris France. CIRAD Forêts et Sociétés Montpellier France. Forêts et Sociétés Univ Montpellier CIRAD Montpellier France. Gembloux Agro Bio-Tech University of Liege Liege Belgium. Faculty of Science and Technology Free University of Bolzano Bolzano Italy. Department of Agricultural Food Environmental and Animal Sciences University of Udine Udine Italy. Swiss Federal Institute for Forest Snow and Landscape Research WSL Birmensdorf Switzerland. UFR Biosciences University Félix Houphouët-Boigny Abidjan Côte d'Ivoire. Spatial Ecology and Conservation Laboratory Center for Latin American Studies University of Florida Gainesville FL USA. Forestry School Tecnológico de Costa Rica TEC Cartago Costa Rica. Fundacion ConVida Universidad Nacional Abierta y a Distancia UNAD Medellin Colombia. Field Museum of Natural History Chicago IL USA. Center for Trop

Species' traits and environmental conditions determine the abundance of tree species across the globe. The extent to which traits of dominant and rare tree species differ remains untested across a broad environmental range, limiting our understanding of how species traits and the environment shape forest functional composition. We use a global dataset of tree composition of >22,000 forest plots and 11 traits of 1663 tree species to ask how locally dominant and rare species differ in their trait values, and how these differences are driven by climatic gradients in temperature and water availability in forest biomes across the globe. We find three consistent trait differences between locally dominant and rare species across all biomes; dominant species are taller, have softer wood and higher loading on the multivariate stem strategy axis (related to narrow tracheids and thick bark). The difference between traits of dominant and rare species is more strongly driven by temperature compared to water availability, as temperature might affect a larger number of traits. Therefore, climate change driven global temperature rise may have a strong effect on trait differences between dominant and rare tree species and may lead to changes in species abundances and therefore strong community reassembly.

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Prediction of the bridge monitoring data based on support vector machine

Prediction of the bridge monitoring data based on support ve...

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International Conference on Natural Computation (ICNC)

作者： Hao Tang Guangwu Tang Libo Meng State Key Laboratory of Bridge Engineering Structural Dynamics China Merchants Chongqing Communications Technology Research & Design Institute Co. Ltd Chongqing China

ISBN: (纸本)9781467376808

According to the mass health monitoring data accumulated of bridge structure for a long time, this paper proposes a method for reconstitute the time series in phase space. Since the phase points are regressed by support vector machine (SVM), the relevant time series of past behavior patterns are established. Then, it could infer the future development trend and form the basis of the online security early warning of bridge structure. The strain and tilt monitoring data of Pian Yan-zi bridge in Chongqing are analyzed and compared with the prediction data of the auto regression moving average (ARMA). The results show that: (1) as to the bridge monitoring data, the prediction accuracy of SVM is better than that of ARMA; (2) With the increase of the number of the prediction steps, the prediction accuracy of ARMA drops dramatically. And ARMA is only applicable for short-term prediction while SVM is able to predict a longer period of time. (3) SVM prediction requires a smaller size of samples for modeling but with higher prediction efficiency.

关键词： Support vector machines bridges Monitoring Time series analysis Predictive models Strain Kernel

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Fatigue performance analysis and experimental study of steel trusses integral joint based on multi-scale FEM 4th

Fatigue performance analysis and experimental study of steel...

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4th International Symposium on Life-Cycle Civil engineering, IALCCE 2014

作者： Hui-Li, Wang Si-Feng, Qin State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian China Institute of Bridge Engineering Dalian University of Technology Dalian China Materials Fracture Mechanics Dalian University Research Center for Numerical Test Dalian China

ISBN: (纸本)9781138001206

The fatigue performance of steel truss integral joint is analyzed. Taking steel trusses as the engineering background, a model fatigue test is taken. Adapt multi-scale FEM to analysis the fatigue performance of steel truss integral joint, compared with the test results. Multi-scale finite element results and fatigue experimental test values is similar. Test results showed that after loading two million times, structural fatigue performance meets the design requirements. The micro-scales elements are adopted for integral joint part. The m-scales elements are adopted for other components, the connection elements are used to connect beam elements and solid elements. Multi-scale FEM provides the guarantee for the fatigue life forecast, so as to simplify calculation. This method is high efficient and feasible. © 2015 Taylor & Francis Group, London.

关键词： Trusses

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Real-time hybrid testing on a girder bridge model by using shaking-table and actuator 6

Real-time hybrid testing on a girder bridge model by using s...

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作者： Yang, Cheng-Yu Dong, Gao-Jie Ren, Xiao-Song You, Shawn Schellenberg, Andreas Dept. of Bridge Engineering State Key Laboratory of Disaster Reduction in Civil Engineering Tongji University Shanghai China Research Institute of Structural Engineering and Disaster Reduction Tongji University Shanghai China Research Institute of Structural Engineering and Disaster Reduction Tongji University Shanghai China MTS Systems Corporation Eden PrairieMN United States Pacific Earthquake Engineering Research Center University of California BerkeleyCA United States

Real-time hybrid test method, an innovative dynamic testing method combining pseudo-dynamic test method, shaking-table testing method, substructure analysis technique and numerical integration algorithm, is believed to be a promising solution to testing structures subjected to earthquake loading. The application of real-time hybrid testing on a girder bridge model was recently performed in Tongji University by using shaking-table and actuator. The prototype model is a single-span girder bridge. In order to study different kinds of hybrid simulation and its feasibility, three different applications based on the same prototype model was carried out: 1) the first test is hybrid test with single actuator;2) the second test is hybrid test with single shaking-table and 3) the third test is a hybrid application by using both shaking-table and actuator. The testing procedure and result of the above three hybrid applications was reported in this paper. The feasibility of the real-time hybrid testing method was also discussed. © International Conference on Advances in Experimental structural engineering. All rights reserved.

关键词： Actuators

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Shake table study of bridge with precast post-tensioned segmental columns

Shake table study of bridge with precast post-tensioned segm...

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10th Asia Pacific Transportation Development Conference - Challenges and Advances in Sustainable Transportation Systems: Plan, Design, Build, Manage, and Maintain

作者： Zhang, Nasi Lan, Haiyan Gao, Wenjun Tang, Guangwu Lee, George University at Buffalo State University of New York Structural and Environmental Engineering 206 Ketter Hall Buffalo NY 14260 United States State Key Laboratory of Bridge Structural Dynamics Chongqing 400067 China Structural and Environmental Engineering University at Buffalo State University of New York 429 Bell Hall Buffalo NY 14260 United States

ISBN: (数字)9780784478363

ISBN: (纸本)9780784413364

Precast, post-tensioned segmental bridge construction has been widely used in non-seismic regions in the U.S. for the objectives of accelerated bridge construction (ABC), higher quality control, less traffic disruption, and better workman safety. However, use of segmental bridges in moderate and high seismic regions is limited due to insufficient understanding of its behavior. This paper presents the results of a series of shake table tests on large-scale bridges with pre-cast, post-tensioned, concrete segmental columns. The seismic behavior of segmental columns was observed, segmental joint opening and closing were studied, and the self-center capability of segmental bridge was analyzed. This research is a U.S.-PRC international cooperative project established by the Multidisciplinary Center for Earthquake engineering Research, University at Buffalo, the state University of New York, under contract with the Federal Highway Administration (Contract No. DTFH61-07-C-00020), and the Chongqing Communication Research and Design Institute, state key laboratory of bridge structural dynamics, Chongqing, China, with the International Science & Technology Cooperation Program of China (Project No.: 2011DFA83300). © 2014 American Society of Civil Engineers.

关键词： Seismology

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Simulation experiment of rockmass loosening induced by excavation load transient unloading

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Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and engineering 2015年 34卷 2941-2947页

作者： Luo, Yi Lu, Wenbo Chen, Ming Yan, Peng Hubei Key Laboratory of Road-bridge and Structure Engineering Wuhan University of Technology WuhanHubei430070 China School of Civil Engineering and Architecture Wuhan University of Technology WuhanHubei430070 China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University WuhanHubei430072 China Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering Ministry of Education Wuhan University WuhanHubei430072 China

In order to study the loosening effect induced by rock mass excavation under high in-situ stress, a laboratory experimental simulation system was designed. By the rapid failure of a rock bar, the system is capable of simulating rapid unloading for jointed rock mass, thus is able to simulate the loosening effect of jointed rock mass under excavation load transient unloading(ELTU), by which, the relationship of in-situ stress level and structural plane opening displacement can be studied. Regression analysis results show that, the opening displacement value is in positive relationship with the square value of in-situ stress. The proportion of displacement on each joint in the total displacement induced by excavation load transient unloading is dependent on the amount and location of joints. ©, 2015, Academia Sinica. All right reserved.

关键词： Rock mechanics

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Time-varying LQG control for vibration of coupled vehicle-bridge system

Time-varying LQG control for vibration of coupled vehicle-br...

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2013 International Conference on Precision Mechanical Instruments and Measurement Technology, ICPMIMT 2013

作者： Song, G. State Key Laboratory of Bridge Structural Dynamics China Merchants Chongqing Communications Research and Design Institute Co. Ltd Chongqing China

Time-varying linear quadratic Gaussian (LQG) control for vibration of coupled vehiclebridge system is studied. The vehicle is modeled as a moving mass model with three degrees of freedom, which consists of vehicle body, bogie and wheel. Active suspensions are adopted for the primary and secondary ones, and the control forces are produced by two actuators placed between the bogie and wheel, and between the vehicle body and the bogie, respectively. Vehicle-bridge coupling systems are time-dependent, which lead to the time-varying Riccati differential equation and the time-varying Kalman-Bucy filter equation in the LQG controller design. However, both of them are solved precisely via precise integration method and symplectic conservative perturbation method. In the example, the time history responses of the bridge and the vehicle were calculated respectively for the vehicle with passive suspensions or with active suspensions. Numerical results show that with active suspensions adopted, ride comfort can be improved when the vehicles passing through the bridge. © 2013 Trans Tech Publications Ltd, Switzerland.

关键词： Wheels

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A protein engineered to selectively bind uranyl with femtomolar affinity

A protein engineered to selectively bind uranyl with femtomo...

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第八届全国化学生物学学术会议

作者： Lu Zhou Mike Bosscher Changsheng Zhang Salih zubuku Liang Zhang Wen Zhang Charles J.Li Jianzhao Liu Mark P.Jensen Luhua Lai Chuan He Department of Chemistry and Institute for Biophysical Dynamics The University of Chicago BNLMS State Key Laboratory for Structural Chemistry of Unstable and Stable SpeciesCollege of Chemistry and Molecular Engineering and Center for Quantitative BiologyPeking University Center for Life Sciences Peking University Chemical Sciences and Engineering Division Argonne National Laboratory

Uranyl(UO),the predominant aerobic form of uranium,is present in the ocean at the concentration of～3.2 ppb（13.7 nM）.This concentration equates to 4.5 billion tons of uranium in seawater,dwarfing traditional ***,competition among various metal ions and naturally occurring ligands has limited successful enrichment of uranyl fro in this vast resource in *** we report the engineering and rational development of a uranyl-binding protein with a K of 7.4 femtomolar（fM）

关键词： protein design uranium sequestration and remediation metalloprotein

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