检索结果-内蒙古大学图书馆

SSRN 2021年

作者： Lu, Rongwei Guan, Xinchun Zhang, Chenchen Kou, Yufeng Li, Jinglu Li, Yazhao Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Harbin Institute of Technology Harbin150090 China

According to the performance requirements of concrete repair materials, a new cement-based permeable crystalline repair material（CCRM） was prepared, and its repair performance and repair mechanism were studied by means of macro mechanical property test, micro ESEM and XRD. The experimental results show that the prepared repair material not only has good flow performance and strength, but also enhances the strength of the repair interface, so that the repair interface is no longer the weak point of the repaired specimen. Through the observation of the microstructure of the repaired specimen, it is found that CCRM can penetrate into the interface of the repaired specimen to form a cross transition zone, and then form a better integration with the repaired specimen, with very good compatibility. Through the test of CCRM repair products by XRD and TG, it is found that there is an active component in CCRM, which can consume calcium hydroxide to form a complex, promote the transformation of calcium carbonate and C-S-H, and then enhance the repair effect. © 2021, The Authors. All rights reserved.

关键词： Repair

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Deep-Learning-Based Bridge Condition Assessment by Probability Density Distribution Reconstruction of Girder Vertical Deflection and Cable Tension Using Unsupervised Image Transformation Model 10th

Deep-Learning-Based Bridge Condition Assessment by Probabili...

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10th European Workshop on Structural Health Monitoring, EWSHM 2020

作者： Xu, Yang Tian, Yadi Zhang, Yufeng Li, Hui Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Key Lab of Structures Dynamics Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China State Key Laboratory of Safety and Health for Inservice Long Span Bridges Nanjing211112 China

ISBN: (纸本)9783030649074

This study proposes a deep-learning-based condition assessment approach by reconstructing marginal probability density distributions of girder vertical deflection (GVD) and cable tension (CT) using unsupervised image transformation (UNIT) model for a real cable-stayed bridge. 27 and 139 sensors of GVD and CT are distributed along the full bridge, and both the sampling frequencies are 2 Hz. First, vehicle-induced components of GVD and CT are extracted by data pre-processing while the temperature-induced components are removed, a time window of 3 h with a sliding length of 10 min is used to obtain original GVD and CT segments, and the corresponding margin probability density distributions (PDFs) are calculated by kernel density estimation. The training and test sets consist of 2986 and 6236 PDFs, respectively. The proposed UNIT model consists of a series of variational autoencoders (VAEs) and generative adversarial networks (GANs). Both the PDFs of GVD and CT are used as inputs. Then, the proposed UNIT model is updated by solving the mini-max problem of training GANs, in which VAEs act as generative models. Finally, the Wasserstein distance between the predicted and ground-truth PDFs of CT acts as the indicator of bridge condition change. Results show that specific modes of PDF variations induced by SHM system upgrade, cable damage, data anomaly, and traffic jam can be recognized to assess bridge condition. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Deep learning

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Discovering Governing Equations by Machine Learning implemented with Invariance

arXiv

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arXiv 2022年

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

The partial differential equation (PDE) plays a significantly important role in many fields of science and engineering. The conventional case of the derivation of PDE mainly relies on first principles and empirical observation. However, the development of machine learning technology allows us to mine potential control equations from the massive amounts of stored data in a fresh way. Although there has been considerable progress in the data-driven discovery of PDE, the extant literature mostly focuses on the improvements of discovery methods, without substantial breakthroughs in the discovery process itself, including the principles for the construction of candidates and how to incorporate physical priors. In this paper, through rigorous derivation of formulas, novel physically enhanced machining learning discovery methods for control equations: GSNN (Galileo Symbolic Neural Network) and LSNN (Lorentz Symbolic Neural Network) are firstly proposed based on Galileo invariance and Lorentz invariance respectively, setting forth guidelines for building the candidates of discovering equations. The adoption of mandatory embedding of physical constraints is fundamentally different from PINN in the form of the loss function, thus ensuring that the designed Neural Network strictly obeys the physical prior of invariance and enhancing the interpretability of the network. By comparing the results with PDE-NET in numerical experiments of Burgers equation and Sine-Gordon equation, it shows that the method presented in this study has better accuracy, parsimony, and interpretability. © 2022, CC BY.

关键词： Numerical methods

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Optimal overlays for preservation of concrete in cold climate: decision-making by the method of fuzzy comprehensive evaluation combined with AHP

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Journal of Infrastructure Preservation and Resilience 2021年第1期2卷 1-16页

作者： Li, Zhipeng Dang, Yudong Tang, Zhen Xie, Ning Lu, Shuang Shi, Xianming Department of Civil & amp Environmental Engineering Washington State University PullmanWA99164-2910 United States Yunnan Key Laboratory of Building Structure and New Materials Yunnan Institute of Building Research Kunming650223 China Key Lab of Structure Dynamic Behavior and Control Ministry of Education Heilongjiang Harbin150090 China School of Civil Engineering Harbin Institute of Technology Heilongjiang Harbin150090 China Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials University of Jinan Shandong Jinan250022 China

Overlays have been extensively employed as an effective preservation or rehabilitation tool to extend the service life of concrete bridges and pavements, especially concrete slabs suffering from salt scaling and abrasion. However, limited attention has been paid to the durability and performance of these overlays which can be jeopardized when they are exposed to freeze/thaw and wet/dry cycles, deicer applications, studded tires, and their coupled effects. Various overlays feature different engineering properties, and they might be only effective in specific service environments but not in others, and research is lacking to examine their ability to adapt to different environments. This study subjected five overlay products on concrete slabs to the combined action of freeze/thaw (F/T) and wet/dry (W/D) cycles with periodical exposure to either 15 wt.% NaCl solution or 15 wt.% MgCl2 solution, to simulate the typical field scenarios in an accelerated manner. The bond strength, splitting tensile strength, and abrasion resistance of the overlaid concrete slabs were tested to evaluate the effectiveness of various overlays against the deicer scaling and the abrasion by studded tires. Based on the experimental data, this study demonstrated a multi-criteria decision-making method, fuzzy comprehensive evaluation (FCE) combined with analytic hierarchy process (AHP), for the selection of optimal overlays in three different service scenarios (e.g., states of Washington and Oregon [USA] and British Columbia [Canada]). The analysis results indicate that one epoxy overlay exhibited the comprehensively best performance and could be a promising candidate in all three given scenarios, another polymer overlay took second place, while the adaptability of the three cement-based overlays varied in different environments. Graphical Abstract: (Figure presented.). © The Author(s) 2021.

关键词： Sodium chloride

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Progressive collapse mechanism of three-dimensional self-centering precast concrete frame with infill walls and slabs

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Engineering Failure Analysis 2025年

作者： Haoran Wang Shuang Li Feng Lin School of Civil Engineering Shenyang Jianzhu University Shenyang 110168 China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education 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 Department of Structural Engineering Tongji University Shanghai 200092 China Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education Shanghai 200092 China

In this study, the effects of infill walls and slabs on the progressive collapse resistance of three-dimension (3D) self-centering precast concrete (PC) frame under corner column failure, middle column failure and internal column failure scenarios were numerically investigated. Based on the verified numerical modeling methods, the failure modes and collapse mechanism of twelve 3D self-centering PC frames were analyzed. The results indicated that the number of spans connected to the failure column will directly influence the progressive collapse resisting-capacity of 3D self-centering PC frames. Compared with slabs, infill walls improved the progressive collapse resistance of 3D self-centering PC frame more obviously. For failure span with small aspect ratio, the presence of infill walls and slabs did not alter the failure mode of the structure. With the aspect ratio of the failure span increased, for 3D self-centering infilled PC frame, the stronger constraint of surrounding frame enhanced the overall stiffness of the infill walls, resulting in a change in the failure mode of the frame. When the slab was arranged, since the larger stiffness of the slabs improved the shear capacity of the beam section, the main concrete damage were still concentrated at the beam ends. A simplified calculation method considering the resistance contribution of structural and non-structural members was proposed to predict the vertical resistance of 3D self-centering PC frame structures under different failure column scenarios in the compressive arch action (CAA) stage.

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Local buckling of stainless steel stub columns with novel octagonal hollow sections

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Engineering structures 2025年 338卷

作者： Zhong, Yukai Jiang, Ke Chen, Man-Tai Su, Andi Zhao, Ou Research Center for Wind Engineering and Engineering Vibration Guangzhou University Guangzhou China School of Civil and Environmental Engineering Nanyang Technological University Singapore Department of Civil and Natural Resources Engineering University of Canterbury Christchurch New Zealand State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai200240 China Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure Department of Civil Engineering Shanghai Jiao Tong University Shanghai200240 China Key Lab of Structures Dynamic Behaviour and Control of the Ministry of Education Harbin Institute of Technology Harbin150090 China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China

Octagonal hollow section, a novel type of polygonal hollow sections, combines the advantages of traditional circular and rectangular hollow sections while mitigating their limitations, with higher load-carrying capacities over rectangular hollow sections due to smaller plate element widths and better constructability over circular hollow sections owing to multiple flat faces providing operation platforms for welded and bolted connections. The present paper reports experimental and numerical studies on the local buckling behaviour of stainless steel octagonal hollow sections under axial compression. The testing programme included axial compression tests on fifteen stainless steel octagonal hollow section stub column specimens with five different outer cross-section dimensions and three different wall thicknesses, as well as tensile coupon tests and initial local geometric imperfection measurements. In parallel with the testing programme, a numerical modelling programme was carried out, with finite element models developed and validated against the test results and afterwards adopted to carry out parametric studies. The test and numerical data were used to evaluate the applicability of relevant design rules, as specified in the European code, American specification and ASCE standard, to stainless steel octagonal hollow sections. The evaluation results generally revealed that (i) the three sets of codified slenderness limits were unsafe when used for cross-section classification of stainless steel hexagonal hollow sections, (ii) the European code and American specification resulted in overall accurate and consistent cross-section compression resistance predictions for stainless steel octagonal hollow sections, but still with some overly conservative predictions for non-slender cross-sections and slightly unsafe predictions for those at the boundary of non-slender and slender cross-sections, and (iii) the ASCE standard provided overall scattered and inaccurate cross-sec

关键词： Welding codes

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Buckling behaviour of S700 high strength cold-formed steel built-up I-section columns

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Journal of Constructional Steel Research 2025年 233卷

作者： Zhuo Wang Chicheng Ma Hua Yang Andi Su 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 State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Nanning Guangxi 530004 China

High strength cold-formed steel (CFS) built-up sections have been widely used in the construction sector, mainly due to high load-bearing capacities and flexible cross-section shapes. To further broaden the knowledge and develop efficient design provisions for high strength CFS built-up sections, experiments and numerical simulations were conducted to investigate the local–flexural interactive buckling behaviour and resistances of S700 high strength CFS built-up I-section columns. In the physical experiments, two identical unlipped channel sections were adopted to assemble each built-up I-section in a back-touching configuration with self-tapping screws. Material testing and measurements of initial geometric imperfections were first conducted; nine column specimens of two cross-sections – 90 × 70 × 2.9 and 160 × 100 × 2.9 were employed and then tested under pin-ended boundary conditions. In the numerical simulations, finite element (FE) models were developed and observed to precisely capture experimental observations. A parametric study was then conducted to derive additional numerical data across a wider range of geometric parameters and member slenderness. After that, the effective width method (EWM) in the European code and American specification, and the direct strength method (DSM) in the American specification were assessed, according to the experimental and numerical results, for their applicability to S700 high strength CFS built-up I-section columns failing by minor-axis local–flexural interactive buckling. The assessment results showed that the EWM yielded scattered and conservative results, while the DSM resulted in relatively accurate but still overall conservative resistance predictions. Therefore, a revised AISI design approach was proposed to improve design consistency and accuracy, with its reliability also verified.

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Interface Shear Analysis of UHPC-NC with U-Shaped Shear Stud

引用

ce/papers 2023年第5期6卷 1338-1343页

作者： Lu, Ya Lin, Lanri Zhang, Xing Shi, Xinbo Wang, Xiao Wang, Hao Yang, Tao Zhang, Chengwu Wang, Rui Wu, Xiangguo School of Civil Engineering Harbin Institute of Technology Harbin150090 China College of Civil Engineering Fuzhou University Fuzhou China CGN New Energy Holdings Co. Ltd China Heilongjiang Construction Group Co. Ltd China Heilongjiang Wujian Construction Engineering Co. Ltd China Jiangxi Building Materials Research and Design Institute Co. Ltd China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of the Industry and Information Technology Harbin Institute of Technology Harbin150090 China

The composite structure composed of ultra-high performance concrete (UHPC) and normal concrete (NC) has been widely applied to engineering structures. U-shaped shear studs play an important role in the combination of the UHPC-NC interface. To investigate the interface shear characteristics of UHPC-NC with U-shaped shear studs, the numerical model with 14 various parameters is calculated based on the interface push tests. The influences of diameter, stud number, NC elastic modulus, NC compressive strength on the shear characteristics of the UHPC-NC interface are analyzed. The results show that the load-slip curves of the UHPC-NC interface with a U-shaped shear stud have three stages: elastic stage, elastoplastic stage and descending stage. The fitting formula with the power function as the basic function can well express the influence law of diameter on the interface shear capacity. The interface shear capacity is not sensitive to the elastic modulus and compressive strength of NC, and it does not increase or decrease with the increase of stud number, the shear strength of a single stud tends to be constant. © 2023 Ernst & Sohn GmbH.

关键词： Compressive strength

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A change-point detection method for detecting and locating the abrupt changes in distributions of damage-sensitive features of SHM data, with application to structural condition assessment

arXiv

引用

arXiv 2021年

作者： Lei, Xinyi Chen, Zhichng Li, Hui Wei, Shiyin Key Lab of Intelligent Disaster Mitigation The Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Key Lab of Structures Dynamic Behavior and Control The Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China

Diagnosing the changes of structural behaviors using monitoring data is an important objective of structural health monitoring (SHM). The changes in structural behaviors are usually manifested as the feature changes in monitored structural responses;thus, developing effective methods for automatically detecting such changes is of considerable significance. Existing methods for change detection in SHM are mainly used for scalar or vector data, thus incapable of detecting the changes of the features represented by complex data, e.g., the probability density functions (PDFs). Detecting the abrupt changes occurred in the distributions (represented by PDFs) associated with the damage-sensitive features extracted from SHM data are usually of crucial interest for structural condition assessment;however, the SHM community still lacks effective diagnostic tools for detecting such changes. In this study, a change-point detection method is developed in the functional data-analytic framework for PDF-valued sequence, and it is leveraged to diagnose the distributional information break encountered in structural condition assessment. A major challenge in PDF-valued data modeling or analysis is that the PDFs are special functional data subjecting to nonlinear constraints. To tackle this issue, the PDFs are embedded into the Bayes space, and the associated change-point model is constructed by using the linear structure of the Bayes space;then, a hypothesis testing procedure is presented for distributional change-point detection based on the isomorphic mapping between the Bayes space and a functional linear space. Comprehensive simulation studies are conducted to validate the effectiveness of the proposed method as well as demonstrate its superiority over the competing method. Finally, an application to real SHM data illustrates its practical utility in structural condition assessment. Copyright © 2021, The Authors. All rights reserved.

关键词： Probability density function

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Functional outlier detection for density-valued data with application to robustify distribution to distribution regression

arXiv

引用

arXiv 2021年

作者： Lei, Xinyi Chen, Zhicheng Li, Hui Key Lab of Intelligent Disaster Mitigation of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China

Distributional data analysis, concerned with statistical analysis and modeling for data objects consisting of random probability density functions (PDFs) in the framework of functional data analysis (FDA), has received considerable interest in recent years. However, many important aspects remain unexplored, such as outlier detection and robustness. Existing functional outlier detection methods are mainly used for ordinary functional data and usually perform poorly when applied to PDFs. To fill this gap, this study focuses on PDF-valued outlier detection, as well as its application in robust distributional regression. Similar to ordinary functional data, detecting the shape outlier masked by the "curve net’’ formed by the bulk of the PDFs is the major challenge in PDF-outlier detection. To this end, we propose a tree-structured transformation system for feature extraction as well as converting the shape outliers to easily detectable magnitude outliers, relevant outlier detectors are designed for the specific transformed data. A multiple detection strategy is also proposed to account for detection uncertainties and to combine different detectors to form a more reliable detection tool. Moreover, we propose a distributional-regression-based approach for detecting the abnormal associations of PDF-valued two-tuples. As a specific application, the proposed outlier detection methods are applied to robustify a distribution-to-distribution regression method, and we develop a robust estimator for the regression operator by downweighting the detected outliers. The proposed methods are validated and evaluated by extensive simulation studies or real data applications. Relevant comparative studies demonstrate the superiority of the developed outlier detection method with other competitors in distributional outlier detection. © 2021, CC BY.

关键词： Statistics

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