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arXiv 2018年

作者： Wei, Shiyin Jin, Xiaowei Li, Hui Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Key Lab of Structures Dynamic Behavior and Control Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China

Physicists use differential equations to describe the physical dynamical world, and the solutions of these equations constitute our understanding of the world. During the hundreds of years, scientists developed several ways to solve these equations, i.e., the analytical solutions and the numerical solutions. However, for some complex equations, there may be no analytical solutions, and the numerical solutions may encounter the curse of the extreme computational cost if the accuracy is the first consideration. Solving equations is a high-level human intelligence work and a crucial step towards general artificial intelligence (AI), where deep reinforcement learning (DRL) may contribute. This work makes the first attempt of applying (DRL) to solve nonlinear differential equations both in discretized and continuous format with the governing equations (physical laws) embedded in the DRL network, including ordinary differential equations (ODEs) and partial differential equations (PDEs). The DRL network consists of an actor that outputs solution approximations policy and a critic that outputs the critic of the actor's output solution. Deterministic policy network is employed as the actor, and governing equations are embedded in the critic. The effectiveness of the DRL solver in Schrödinger equation, Navier-Stocks, Van der Pol equation, Burgers' equation and the equation of motion are discussed. Copyright © 2018, The Authors. All rights reserved.

关键词： Deep learning

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Chemical composition of calcium-silicate-hydrate gels: Competition between kinetics and thermodynamics

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Physical Review Materials 2019年第6期3卷 065603-065603页

作者： Tao Du Hui Li Qi Zhou Zhe Wang Gaurav Sant Joseph V. Ryan Mathieu Bauchy Key Lab of Structures Dynamic Behavior and Control (Harbin Institute of Technology) Ministry of Education 150090 Harbin China School of Civil Engineering Harbin Institute of Technology 150090 Harbin China Physics of AmoRphous and Inorganic Solids Laboratory (PARISlab) Department of Civil and Environmental Engineering University of California Los Angeles California 90095 USA Laboratory for the Chemistry of Construction Materials (LC2) Department of Civil and Environmental Engineering University of California Los Angeles California 90095 USA California Nanosystems Institute (CNSI) University of California Los Angeles California 90095 USA Energy and Environment Directorate Pacific Northwest National Laboratory Richland Washington 99352 USA

Although concrete is the world's most widely used manufactured material, basic questions persist regarding the nature of its binding phase, namely, the calcium-silicate-hydrate (C-S-H) gel. Here, based on reactive molecular dynamics simulations, we address the following fundamental question: Is the chemical composition of C-S-H controlled by the kinetics or thermodynamics of its precipitation? As a major outcome of this study, we demonstrate that the average stoichiometry of the C-S-H gel forming upon the hydration of ordinary portland cement (i.e., Ca/Si = 1.75) is determined by the composition of the C-S-H phase presenting the fastest precipitation kinetics, rather than the highest thermodynamic stability.

关键词： Amorphous materials Gels Molecular dynamics

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Wind load prediction of large-span dry coal sheds based on grnn and its application 9th

Wind load prediction of large-span dry coal sheds based on g...

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9th International Structural Engineering and Construction Conference: Resilient structures and Sustainable Construction, ISEC 2017

作者： Sun, Ying Yang, Lin Wu, Yue Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education School of Civil Engineering Harbin Institute of Technology Harbin China School of Civil Engineering Harbin Institute of Technology Harbin China

ISBN: (纸本)9780996043748

The distribution and fluctuation of wind load on large-span dry coal sheds are complicated. Wind load on typical shape of roofs can be sometimes determined based on the wind tunnel tests carried out on roofs of similar shape. To expand the application scope of the test data, Generalized Regression Neural Network (GRNN) is introduced. The prediction models on large-span dry coal are given, where the wind load is expressed by eight parameters: mean, RMS, skewness, kurtosis of wind pressure coefficients, three auto-spectral parameters (including descendent slope in high frequency range, peak reduced spectrum and reduced peak frequency) and coherence exponent for cross-spectra. Cross validation and trails are carried out to determine the parameter in the GRNN model. Further, the wind load prediction is applied on a dry coal shed shell. The wind-induced responses are calculated and compared with the results of wind tunnel tests, with extremely close result. Therefore, it can be concluded that GRNN is feasible in predicting wind load on roof structures. Copyright © 2017 ISEC Press.

关键词： Neural networks

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Numerical simulation and experimental validation of moisture-heat coupling for saturated frozen soils

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Research in Cold and Arid Regions 2017年第3期9卷 250-257页

作者： Zhi Ming Li Jian Chen Kai Sun Bin Zhang Key Lab of Structures Dynamic Behavior and Control (Harbin Institute of Technology) Ministry of Education School of Civil Engineering Harbin Institute of Technology Heilongjiang Water Conservancy Science Research Institute

In seasonally frozen regions,freezing-and-thawing action is the main cause responsible for the destruction of canals,which is closely linked to the temperature gradient and water *** investigate the behaviour of soils under freezing-and-thawing actions,many numerical models have been established that consider the important coupling of moisture transport and temperature evolution;but they contain excessive parameters,some of which are rather difficult to *** on the well-known Harlan's theory,a simple moisture-heat coupling model was recently proposed to quantify the coupled moisture-heat transport performance of soils in terms of the central temperature and *** mathematical module of COMSOL Multiphysics was further employed to solve the governing equations *** validate our model,a thorough experimental scheme was carried out in our *** measured temperature distribution was found to be consistent with the predicted results.

关键词： saturated frozen soil moisture-heat coupling freezing-and-thawing action canal

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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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A refined cellular automata method for predicting failure patterns of masonry wall panels

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IOP Conference Series: Earth and Environmental Science 2019年第2期233卷

作者： Pengcheng Li Xiuli Ma Bei Du Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin 150090 China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin 150090 China School of Electronics and Information Engineering Harbin Vocation and Technical College Harbin 150081 China.

In view of the inaccuracy of the existing cellular automata (CA) technique in predicting failure patterns of masonry wall panels, this paper proposed a refined CA method which contains two measures to promote the precision of results. The optimization of matching criterion based on Taylor expansion updates the definition of state values for the CA model of wall panels and improves the accuracy of predicting the failure patterns of wall panels with opening. Besides, the post-processing of noise reduction explains the discontinuity of cracks in wall panels from the perspective of noise based on two proposed theorems, which improves the prediction of the failure patterns in appearance, continuity and clarity of cracks. Meanwhile, the difference functions and similarity of wall panels are introduced to evaluate the predicting results. Moreover, the combination of two measures shows the brilliant capacity in enhancing the accuracy and efficiency of prediction.

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Studyon failure modeof husk mortar energy-saving wallboards 9th

Studyon failure modeof husk mortar energy-saving wallboards

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9th International Structural Engineering and Construction Conference: Resilient structures and Sustainable Construction, ISEC 2017

作者： Zhang, Yu Zhang, Qingwen Zhao, Jian Zhou, Guangchun Key Lab of Structures Dynamic Behavior and Control of Ministry of Education Harbin China Key Lab of Smart Prev. and Mitigation of Civ. Eng Disasters of the Min. of Indust. and Info. Technol Harbin China School of Civil Engineering Harbin Institute of Technology Harbin China

ISBN: (纸本)9780996043748

This paper focuses on husk mortar wallboard, which is a new type of energy-saving composite wallboard with new materials and complex working mechanism. There are eight total different dimensioned panels tested. Six of them are openings (window or door), with different opening rates;the other two are full panels with same dimensions. Based on the experimental data, they are analyzed under both horizontal and vertical direction loading, combined with the finite element analysis to reveal the working characteristics. The finite element model of husk mortar energy-saving wallboards is established by ANSYS software. Finally, the finite element results are compared with the experimental results from three aspects: ultimate load, failure mode and load displacement curve, which verifies the correctness of the finite element model. Copyright © 2017 ISEC Press.

关键词： Mortar

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Effects of Rice Husk Ash on Strength and Permeability of Ultra-high Performance Concrete

Effects of Rice Husk Ash on Strength and Permeability of Ult...

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第九届水泥混凝土国际会议

作者： Huanghuang HUANG Xiaojian Gao Guangshuai Han School of Civil Engineering Harbin Institute of Technology Key Lab of Structure Dynamic Behavior and Control(Harbin Institute of Technology).Ministry of Education

This paper aims to investigate the effects of rice husk ash(RHA) on strength and penneability of ultra-high performance concrete(UHPC).The RHA was manufactured by calcining rice husk at temperature of 500 "C and incorporated in UHPC mixture to replace different ratio of SF by *** every mixture,fluidity,compressive and flexural strength,permeability before and after loading and pore structure were measured at different curing *** results show that the addition of RHA can enhance the compressive strength of UHPC at 3,28 and 120 days and refine the pore structure of UHPC measured by MIP method at 3 and 28 *** can also improve the permeability of UHPC before exposure to *** vertical loading or lateral loading,samples incorporated RHA behave better anti-permeability than the control mixture when the loading does not exceed 70%of load ***,RHA may bring about an increase in permeability of UHPC when being subjected to very high levels of loading(above80%).

关键词： Ultra-high performance concrete Rice husk ash Strength development Permeability Loading

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Strain sensor made by thick-film resistors on substrates of glass ceramic 11

Strain sensor made by thick-film resistors on substrates of ...

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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： Guan, Xinchun Wen, Ming Li, Hui Ou, Jinping Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology 73 Huanghe Road Nangang District Harbin150090 China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters Ministry of Industry and Information Technology Harbin Institute of Technology 73 Huanghe Road Nangang District Harbin150090 China

ISBN: (纸本)9781605953304

Thick film resistors (TFRs) were screen printed and fired on fluorophlogopite glass ceramic (FGC) substrates with low elasticity modulus. The mechanical property of FGC and piezoresistivity of TFRs were studied. Test results show the sensor has favorable performance parameters including a sensitivity of 7.888, linearity of 0.716%, repeatability of 0.764% and hysteresis of 0.982% when its input is in the range from 0-3043μϵ. The strain sensors made with TFRs on FGC substrate is possible to be used in SHM of civil engineering.

关键词： Glass ceramics

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Review and analysis on spalling critical temperature of concrete and fibers dosage to prevent spalling at elevated temperatures

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Jianzhu Jiegou Xuebao/Journal of Building structures 2017年第1期38卷 161-170页

作者： Chen, Mingyang Hou, Xiaomeng Zheng, Wenzhong Wu, Bo Key Lab of Structures Dynamic Behavior and Control of China Ministry of Education Harbin Institute of Technology Harbin150090 China State Key Laboratory of Subtropical Building Science South China University of Technology Guangzhou510640 China

The principle of fire safety design is to ensure that concrete structures will not collapse or spall during fire and can be repaired after fire. There is important significance to research the spalling critical temperature of concrete without fibers or with lower fibers and rational fibers dosage to prevent spalling at elevated temperatures. The test results on fire-induced concrete spalling were analyzed. The relationship of spalling critical temperature and concrete cube compressive strength was obtained. Results show that the spalling critical temperature decreases with the increase of concrete compressive *** relationship of volume dosage of polypropylene (PP) fibers and steel fibers to prevent spalling and concrete compressive strength was obtained. The dosage of PP fibers increases linearly with the increase of concrete compressive strength, while the dosage of steel fibers increases with the increase of concrete compressive strength and the relationship can be expressed as an exponent *** is not safe to apply the recommendation in EN 1992-1-2: 2004 'Design of concrete structures: part 1-2: general rules: structural fire design' that the volume dosage 0.22% of PP fibers in concrete to prevent spalling. The proposed formula for fibers dosage will reduce the fire-induced spalling of concrete effectively. © 2017, Editorial Office of Journal of Building structures. All right reserved.

关键词： Steel fibers

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