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Hydraulic Properties of Unsaturated engineering Soils Vegetated with Vetiver Grass in Green Infrastructures 1st

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Hydraulic Properties of Unsaturated Engineering Soils Vegeta...

1st Belt and Road Webinar Series on Geotechnics, Energy, and Environment, BRWSG 2021

作者： Wang, Hao Huang, Junwen Chen, Rui Li, Zhaofeng School of Civil and Environmental Engineering Harbin Institute of Technology Shenzhen Shenzhen518055 China Shenzhen Key Laboratory of Intelligent Structure System in Civil Engineering Harbin Institute of Technology Shenzhen Shenzhen518055 China

ISBN: (纸本)9789811699627

Aiming at green infrastructures which are widely established in countries and regions within the Belt and Road Initiative, both in-situ monitoring and indoor experiments were conducted in the present study. Relationships of hydraulic properties (e.g., soil water characteristic curve and permeability) with root characteristics (e.g., distribution, morphology as well as biomass) and meteorological conditions were investigated. It is found that coarse roots are mainly observed in shallow soils, while fine roots are widely distributed in deep layers. Preferential flow induced by coarse roots and pore clogging due to fine roots are proved in dye-tracer test. The field monitoring is divided into three stages, i.e., T1 (sunny days), T2 (rainy days) and T3 (sunny days after T2). There exist distinct diurnal characteristics of changes of soil suction and water content during the T1 and T3 stages. Moreover, soil suction is negatively relevant with air relative humidity, under absence of rainfalls. Vegetation increases amplitudes of diurnal changes of soil suction and water content. During the T2 stage, diurnal variations of VWC of both vegetated and bare soils are negligible due to rainfalls. Soil air-entry value (AEV) is positively relevant with root biomass. In addition, vegetation improves soil water-holding capability at most vegetation-available suction ranges. As compared to indoor-measured SWCC, field-measured SWCC is more similar to that of ideal coarse-grained soils. Roots improve soil permeability through preferential flows and enhanced water-retention capacity. Results obtained in the present study helps to obtain desired outcomes, i.e., improving feasibility, performance and durability of green infrastructures. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Vegetation

Experimental Study of Fatigue and Sensing Performance of Corroded Smart Steel Wire

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SSRN 2022年

作者： Yan, Cheng Liu, Chengyin Yu, Sheng Xu, Weijie Shenzhen Key Laboratory of Intelligent Structure System in Civil Engineering Harbin Institute of Technology Shenzhen China

Smart steel wire (SSW) is widely used in the health monitoring of cable-stayed bridges as an intelligent sensing instrument of cable force. However, the coupling effect of corrosion and fatigue may cause the measurement misalignment or even fracture of SSW during its service life. To study the fatigue and sensing performance of SSW under corrosion, this paper first presented the sensing performance of SSW according to the Fiber Bragg Grating (FBG) sensing principle, and the fatigue life estimation method of SSW based on the Basquin Equation. Then, the effects of corrosion on the fatigue and sensing performance of SSW were experimentally investigated in terms of the weight loss rate (WLR). Finally, the fatigue life and sensing models for corroded SSW were established and verified using the experimental data. The results demonstrate that the proposed models have good accuracy for the estimation of long-term performance of SSW. © 2022, The Authors. All rights reserved.

关键词： Cable stayed bridges

Variable stiffness design optimization of fiber-reinforced composite laminates with regular and irregular holes considering fiber continuity for additive manufacturing

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Chinese Journal of Aeronautics 2025年第3期38卷 334-354页

作者： Yi LIU Zunyi DUAN Chunping ZHOU Yuan SI Chenxi GUAN Yi XIONG Bin XU Jun YAN Jihong ZHU School of Mechanics Civil Engineering&ArchitectureNorthwestern Polytechnical UniversityXi’an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China Key Lab for Airborne Hi-performance Electro-magnetic Window RISACJinan 130012China School of System Design and Intelligent Manufacturing Southern University of Science and TechnologyShenzhen 518055China State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering MechanicsInternational Research Center for Computational MechanicsDalian University of TechnologyDalian 116024China State IJR Center of Aerospace Design and Additive Manufacturing MIIT Lab of Metal Additive Manufacturing and Innovative DesignNorthwestern Polytechnical UniversityXi’an 710072China

Fiber-reinforced composites are an ideal material for the lightweight design of aerospace structures. Especially in recent years, with the rapid development of composite additive manufacturing technology, the design optimization of variable stiffness of fiber-reinforced composite laminates has attracted widespread attention from scholars and industry. In these aerospace composite structures, numerous cutout panels and shells serve as access points for maintaining electrical, fuel, and hydraulic systems. The traditional fiber-reinforced composite laminate subtractive drilling manufacturing inevitably faces the problems of interlayer delamination, fiber fracture, and burr of the laminate. Continuous fiber additive manufacturing technology offers the potential for integrated design optimization and manufacturing with high structural performance. Considering the integration of design and manufacturability in continuous fiber additive manufacturing, the paper proposes linear and nonlinear filtering strategies based on the Normal Distribution Fiber Optimization (NDFO) material interpolation scheme to overcome the challenge of discrete fiber optimization results, which are difficult to apply directly to continuous fiber additive manufacturing. With minimizing structural compliance as the objective function, the proposed approach provides a strategy to achieve continuity of discrete fiber paths in the variable stiffness design optimization of composite laminates with regular and irregular holes. In the variable stiffness design optimization model, the number of candidate fiber laying angles in the NDFO material interpolation scheme is considered as design variable. The sensitivity information of structural compliance with respect to the number of candidate fiber laying angles is obtained using the analytical sensitivity analysis method. Based on the proposed variable stiffness design optimization method for complex perforated composite laminates, the numerical examples cons

关键词： Variable stiffness composite laminates Discrete material interpolation scheme Normal distribution fiber optimization Discrete fiber continuous filtering strategy Additive manufacturing of composite laminates

A Flexible-Wall Triaxial Permeameter for Localized Characterizations of Soil Suffusion

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SSRN 2022年

作者： Chen, Rui Li, Zhaofeng Luo, Zhiyuan Zhang, Liangliang Tan, Runqiang School of Civil and Environmental Engineering Harbin Institute of Technology Shenzhen China Shenzhen Key Laboratory of Intelligent Structure System in Civil Engineering Harbin Institute of Technology Shenzhen China

A novel flexible-wall triaxial permeameter was developed for localized characterization of soil suffusion. The permeameter is modularized and composed of a loading and permeating module, a pressurized water supply module, an outflow collecting module and a back pressure supply module. In the permeameter, the local pore water pressure can be captured by an invented perforation socket which connects sensors with the specimen through the flexible wall without water leakage, and the local deformation can be measured by photography. Three parallel suffusion tests on complete decomposed granite were carried out using the proposed permeameter. Test repeatability was achieved and the three-stage suffusion process was reproduced, demonstrating the permeameter is effective in producing the soil suffusion. The soil suffusion was better characterized and understood, since a localized indicator and precursor for the suffusion-induced failure might be provided and hydro-mechanical coupling constitutive model could be developed based on the observations from the permeameter. © 2022, The Authors. All rights reserved.

关键词： Soils

Flexible capacitive pressure sensor based on interdigital electrodes with porous microneedle arrays for physiological signal monitoring

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Nanotechnology and Precision engineering 2024年第1期7卷 18-31页

作者： Jiahui Xu Minghao Wang Minyi Jin Siyan Shang Chuner Ni Yili Hu Xun Sun Jun Xu Bowen Ji Le Li Yuhua Cheng Gaofeng Wang School of Electronics&Information MOE Engineering Research Center of Smart Microsensors and MicrosystemsHangzhou Dianzi UniversityHangzhou 310018China Wenzhou Institute of Hangzhou Dianzi University Wenzhou 310018China Key Laboratory of Intelligent Operation and Maintenance Technology&Equipment for Urban Rail Transit of Zhejiang Province College of EngineeringInstitute of Precision Machinery and Smart StructureZhejiang Normal UniversityJinhua 321004China Institute of Guizhou Aerospace Measuring and Testing Technology Guiyang 550009China Unmanned System Research Institute Northwestern Polytechnical UniversityXi’an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518057China

Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and ***,their relatively low sensitivity,linearity,and stability have hindered their large-scale commercial ***,aﬂexible capacitive pressure sensor based on an interdigital electrode structure with two porous microneedle arrays(MNAs)is *** porous substrate that constitutes the MNA is a mixed product of polydimethylsiloxane and *** to its porous and interdigital structure,the maximum sensitivity(0.07 kPa-1)of a porous MNA-based pressure sensor was found to be seven times higher than that of an imporous MNA pressure sensor,and it was much greater than that of aﬂat pressure sensor without a porous MNA ***-element analysis showed that the interdigital MNA structure can greatly increase the strain and improve the sensitivity of the *** addition,the porous MNA-based pressure sensor was found to have good stability over 1500 loading cycles as a result of its bilayer parylene-enhanced conductive electrode *** importantly,it was found that the sensor could accurately monitor the motion of aﬁnger,wrist joint,arm,face,abdomen,eye,and Adam’s ***,preliminary semantic recognition was achieved by monitoring the movement of the Adam’s ***,multiple pressure sensors were integrated into a 33 array to detect a spatial pressure distribu-×*** to the sensors reported in previous works,the interdigital electrode structure presented in this work improves sensitivity and stability by modifying the electrode layer rather than the dielectric layer.

关键词： Capacitive pressure sensor Microneedle array Porous PDMS Interdigital electrode

Load-bearing behaviors of sandwich plates with non-uniformly distributed grid cores: Dynamic impact and blast

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Research Square

Research Square 2024年

作者： Wang, Youlong Yang, Haixia Chen, Jie Ma, Quanjin Song, Yiheng Key Laboratory of Concrete and Prestressed Concrete Structures Ministry of Education School of Civil Engineering Southeast University Nanjing211189 China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China School of Engineering The University of Tokyo Tokyo113-8656 Japan

Sandwich plates with grid-core structures possess extensive applications, and non-uniform grid plates (NUGPs) show enhanced potential under varied loading modes. The current study embarks on an investigation into NUGPs by adjusting the dimensions of transverse and longitudinal grid walls. This comprehensive analysis explores the dynamic responses of these plates when subjected to impact and blast loads, focusing on deformation patterns, damage, and the underlying processes. The findings are illustrated as follows. 1) NUGPs, specifically those with an optimized configuration of grid walls termed the d2 structure, display improved resistance to blast and impact loads compared to their uniformly distributed grid plate counterparts. Notably, designs featuring a less dense grid in the central area yield a more evenly distributed damage pattern under impact loads and a lesser severity of damage from blast loads. 2) The study also reveals that under impact loads, the sandwich structure showcases distinct behaviors through three stages evident in the load-displacement curves: initial localized indentation, followed by overall deformation, and ending with deformation recovery. 3) Moreover, when facing blast loads, the initial response involves rapid plastic deformation of the upper skin, succeeded by compression and buckling of the core. This sequence effectively dissipates energy, acting as a protective shield for the lower skin. 4) The optimized NUGPs design achieves a perfect balance between stiffness and ductility, reducing displacement through adequate stiffness while ensuring the effective absorption of dynamic forces through significant ductility, thus preventing catastrophic failure. This research significantly advances topology optimization for sandwich plates, providing essential insights for designing lightweight structures resilient under various modes. © 2024, CC BY.

关键词： Stiffness

Subway rail transit monitoring by built-in sensor platform of smartphone

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Frontiers of Information Technology & Electronic engineering 2020年第8期21卷 1226-1238页

作者： Jian-li CONG Ming-yuan GAO Yuan WANG Rong CHEN Ping WANG School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China Key Laboratory of High-speed Railway Engineering Ministry of EducationChengdu 610031China College of Engineering and Technology Southwest UniversityChongqing 400716China National&Local Joint Engineering Laboratory of Intelligent Transmission and Control Technology Chongqing 400716China School of System Design and Intelligent Manufacturing Southern University of Science and TechnologyShenzhen 518055China

Smartphone,as a smart device with multiple built-in sensors,can be used for collecting information(e.g.,vibration and location).In this paper,we propose an approach for using the smartphone as a sensing platform to obtain real-time data on vehicle acceleration,velocity,and location through the development of the corresponding application software and thereby achieve the green concept based monitoring of the track condition during subway rail *** tests are conducted to verify the accuracy of smartphones in terms of the obtained data’s standard deviation(SD),Sperling index(SI),and International Organization for Standardization(ISO)-2631 weighted acceleration index(WAI).A vehicle-positioning method,together with the coordinate alignment algorithm for a Global Positioning system(GPS)free tunnel environment,is *** the time-domain integration method,the relationship between the longitudinal acceleration of a vehicle and the subway location is established,and the distance between adjacent stations of the subway is calculated and compared with the actual *** effectiveness of the method is verified,and it is confirmed that this approach can be used in the GPS-free subway tunnel *** is also found that using the proposed vehicle-positioning method,the integral error of displacement of a single subway section can be controlled to within 5%.This study can make full use of smartphones and offer a smart and eco-friendly approach for human life in the field of intelligent transportation systems.

关键词： Acceleration signals Smart monitoring Embedded sensors Smartphones Subway

Soft-Landing Dynamics of a Type of Four-Legged Space Lander

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SSRN 2024年

作者： Shi, Tengfei Shi, Tengfei Yang, Yinping Zhang, Zhijuan Liu, Cuicui Liu, Caishan Ma, Daolin Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and Aerospace Engineering Southwest Jiaotong University Chengdu610031 China State Key Laboratory for Turbulence and Complex Systems College of Engineering Peking University Beijing100871 China Institute of Dynamics and Control College of Mechanical Engineering and Applied Electronics Technology Beijing University of Technology Beijing100871 China China Academy of Space Technology Beijing100094 China School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai200240 China Key Laboratory of Marine Intelligent Equipment and System Ministry of Education Shanghai200240 China

Analyzing the landing dynamics response is essential for enhancing the success rate of surface explorations on Mars, the moon, or asteroids. This paper develops a comprehensive dynamics model for a space lander equipped with four sets of buffer legs, each consisting of a primary strut, two secondary struts, and a footpad, during its soft landing process. The degrees of freedom of the main body and the footpads are defined as generalized coordinates to describe the motion of the space lander. The compression force of the buffer struts is obtained by interpolating real experimental data, and the contact force between the footpad and the ground is calculated using Archimedes law for granular media. Then, the dynamical model for the lander in terms of minimal degrees of freedom can be constructed by applying the Lagrange equations of the second kind. The proposed dynamics model is validated by the experiments of a single-legged lander vertical touchdown and a four-legged lander free touchdown. Moreover, histories of buffer force, acceleration of the main body, and other key physical quantities are computed to investigate the landing process. This highly efficient and accurate dynamics model provides a method to perform extensive simulations to design and optimize a soft landing process. © 2024, The Authors. All rights reserved.

关键词： Landing

Channel Reflection: Knowledge-Driven Data Augmentation for Eeg-Based Bcis

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SSRN 2024年

作者： Wang, Ziwei Li, Siyang Luo, Jingwei Liu, Jiajing Wu, Dongrui Key Laboratory of the Ministry of Education for Image Processing and Intelligent Control School of Artificial Intelligence and Automation Huazhong University of Science and Technology Wuhan430074 China Shenzhen Huazhong University of Science and Technology Research Institute Shenzhen518063 China China Electronic System Technology Co. Ltd. Beijing100089 China School of Civil and Hydraulic Engineering Huazhong University of Science and Technology Wuhan430074 China

A brain-computer interface (BCI) enables direct communication between the human brain and external devices. Electroencephalography (EEG) based BCIs are currently the most popular for able-bodied users. To increase user-friendliness, usually a small amount of user-specific EEG data are used for calibration, which may not be enough to develop a pure data-driven decoding model. To cope with this typical calibration data shortage challenge in EEG-based BCIs, this paper proposes a parameter-free channel reflection (CR) data augmentation approach that incorporates prior knowledge on the channel distributions of different BCI paradigms in data augmentation. Experiments on eight public EEG datasets across four different BCI paradigms (motor imagery, steady-state visual evoked potential, P300, and seizure classifications) using different decoding algorithms demonstrated that: 1) CR is effective, i.e., it can noticeably improve the classification accuracy;2) CR is robust, i.e., it consistently outperforms other data augmentation approaches in the literature;and, 3) CR is flexible, i.e., it can be combined with other data augmentation approaches to further increase the performance. We suggest that data augmentation approaches like CR should be an essential step in EEG-based BCIs. Our code is available online. © 2024, The Authors. All rights reserved.

关键词： Electroencephalography