期刊：
Materials and Design,2011年32(4):2149-2156 ISSN：0261-3069
通讯作者：
Xiao, Yan-Ping
作者机构：
[Pan, Qing-Lin; Li, Wen-Bin; He, Yun-Bin; Xiao, Yan-Ping; Liu, Xiao-Yan] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Peoples R China.;[Pan, Qing-Lin] Minist Educ, Key Lab Nonferrous Mat Sci & Engn, Changsha 410083, Peoples R China.;[Li, Wen-Bin] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Xiao, Yan-Ping] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Peoples R China.
关键词：
A. Non-ferrous metals and alloys;E. Corrosion;F. Microstructure
摘要：
Influence of retrogression and re-aging treatment on the microstructure, strength, exfoliation corrosion, inter-granular corrosion and stress corrosion cracking of an Al-Zn-Mg-Cu alloy has been investigated by means of optical microscope (OM), transmission electron microscope (TEM) and electrochemical impedance spectroscopy (EIS). The results show that retrogression and re-aging treatment can increase the size and the distribution discontinuity of the grain boundary precipitates, and lead to the increase of the corrosion resistance without the loss of strength and ductility. In addition, the analysis of electrochemical impedance spectroscopy shows that retrogression and re-aging treatment can enhance the resistance to exfoliation corrosion. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.
作者：
Li Wen-bin;Pan Qing-lin;Xiao Yan-ping;He Yun-bin;Liu Xiao-yan
期刊：
Transactions of Nonferrous Metals Society of China,2011年(10):2127-2133 ISSN：1003-6326
通讯作者：
Pan, QL
作者机构：
[Li Wen-bin; Pan Qing-lin; Xiao Yan-ping; He Yun-bin; Liu Xiao-yan] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.;[Li Wen-bin] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Pan, QL ] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.;Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.
摘要：
The microstructural evolution and composition distribution of an Al-Zn-Cu-Mg-Sc-Zr alloy during homogenization were investigated by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The results show that severe dendritic segregation exists in Al-Zn-Cu-Mg-Sc-Zr alloy ingot. There are a lot of eutectic phases at grain boundary and the distribution of the main elements varies periodically along interdendritic region. The main eutectic phases at grain boundary are Al7Cu2Fe phase and T (Al2Mg3Zn3). The residual phases are dissolved into the matrix gradually during homogenization with increasing temperature and prolonging holding time, which can be described by a constitutive equation in exponential function. The overburnt temperature of the alloy is 473.9 °C. The optimum parameters of homogenization are 470 °C and 24 h, which is consistent with the result of homogenization kinetic analysis.
作者机构：
[Zhou, Z. -M.; Zhang, J. -F.; Long, Q.] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.
通讯机构：
[Zhang, J. -F.] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.
关键词：
Multi-objective model;Traffic management strategy;Intersection signal controlling;Fuzzy analytic process;Q-learning algorithm
摘要：
Traffic signals are one of the main traffic management tools used to control traffic flow on the roads and should reflect traffic managers' intentions in different tasks. This paper showed a multi-objective optimization model, and its algorithm was aimed at the intricate structure of traffic control. First, the indexes of queuing lengths, delay times, and stop times were chosen as the evaluation indexes of optimization model. Second, the weight of the optimization indexes was confirmed with a fuzzy analytic process (FAP) according to the traffic managers' strategy. Finally, the multi-objective optimization model was solved with the Q-learning algorithm, and thus the signal control scheme of the intersection was produced in real-time while considering the traffic management strategy. The results of the simulation showed that the method could effectively improve traffic efficiency at the intersection, and at the same time, the intentions of the traffic managers could be fully embodied.
摘要：
The mechanical performance of recycled aggregate concrete (RAC) is investigated. An experiment on the complete stress-strain curve under uniaxial compression loading of RAC is carried out. The experimental results indicate that the peak stress, peak strain, secant modulus of the peak point and original point increase with the strength grade of RAC enhanced. On the contrary, the residual stress of RAC decreases with the strength grade enhancing, and the failure of RAC is often broken at the interface between the recycled aggregate and the mortar matrix. Finally, the constitutive model of stress-strain model of RAC has been constituted, and the results from the constitutive model of stress-strain meet the experiment results very well.
作者机构：
[Yi Weijian; Feng Haoxiong] Hunan Univ, Sch Civil Engn, Changsha 410082, Hunan, Peoples R China.;[Feng Haoxiong] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.
会议名称：
2nd International Workshop on Renewable Energy and Development (IWRED)
会议时间：
APR 20-22, 2018
会议地点：
Guilin, PEOPLES R CHINA
会议主办单位：
[Feng Haoxiong;Yi Weijian] Hunan Univ, Sch Civil Engn, Changsha 410082, Hunan, Peoples R China.^[Feng Haoxiong] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.
会议论文集名称：
IOP Conference Series-Earth and Environmental Science
摘要：
The MCFT on shear theoretical calculation method in reinforced concrete beams is expressed by the mathematical relationship based on the theory of MCFT, and the theoretical calculation formula is simplified. Finally the results with shear theoretical calculation method of simplified MCFT can be well fit with the test datas. That shows the simplified theoretical calculation method of shear is reasonable, thus another simple method for shear calculation of the reinforced concrete T beams is provided.
摘要：
The response surface method (RSM) is one of the main approaches for analyzing reliability problems with implicit performance functions. An improved adaptive RSM based on uniform design (UD) and double weighted regression (DWR) was presented. In the proposed method, the basic principle of the iteratively adaptive response surface method is applied. Uniform design is used to sample the fitting points. And a double weighted regression system considering the distances from the fitting points to the limit state surface and to the estimated design points is set to determine the coefficients of the response surface model. Compared with the conventional approaches, the fitting points selected by UD are more representative, and a better approximation in the key region is also observed with DWR. Numerical examples show that the proposed method has good convergent capability and computational accuracy.
作者：
Li Wenbin*;Pan Qinglin;Zou Liang;Liang Wenjie;He Yunbin;Liu Junsheng
期刊：
Rare Metals,2009年(1):102-106 ISSN：1001-0521
通讯作者：
Li Wenbin
作者机构：
[Pan Qinglin; Li Wenbin; Liang Wenjie; Zou Liang; He Yunbin; Liu Junsheng] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.;[Li Wenbin] Hunan City Univ, Dept Civil Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Li Wenbin] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.
摘要：
Five kinds of Al-Zn-Mg-Cu-Zr based alloys with different Sc additions were prepared by ingot metallurgy. The effects of minor Sc on the microstructure and mechanical properties of Al-Zn-Mg-Cu-Zr based alloys were investigated using tensile tests, optical microscopy (OM), and transmission electron microscopy (TEM). The results show that the ultimate tensile strength and yield strength are improved by 94 and 110 MPa, respectively, and the elongation to failure remains at a reasonable extent (11.1%) in the Al-Zn-Mg-Cu-Zr based alloy with 0.21 wt.% Sc addition after solution heat treatment at 475°C for 40 min and then aged at 120°C for 24 h. The addition of minor Sc induces the formation of Al3(Sc,Zr) particles, which are highly effective in refining the cast microstructures, retarding recrystallization, and pinning dislocations. The increment of strength is attributed mainly to fine grain strengthening, precipitation strengthening of Al3(Sc,Zr) particles, and substructure strengthening.
期刊：
Journal of Constructional Steel Research,2018年144:153-165 ISSN：0143-974X
通讯作者：
Liu Jing
作者机构：
[Liu Jing; Ding Fa-xing; Yu Zhi-wu] Cent S Univ, Sch Civil Engn, Changsha 410075, Hunan, Peoples R China.;[Liu Jing; Li Yong-suo] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.;[Liu Xue-mei] Queensland Univ Technol, Sch Civil Engn & Built Environm, Brisbane, Qld 4000, Australia.
通讯机构：
[Liu Jing] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Hunan, Peoples R China.
关键词：
Steel-concrete composite beams;Quasi static test;Hysteretic performance;Degree of shear connection
摘要：
This study aimed to investigate the seismic behavior of simply supported steel-concrete composite I beam and box beam through a quasi-static experimental study. A total of 22 composite beams included in the experiments, and parameters including shear connection degree, transverse reinforcement ratio, longitudinal reinforcement ratio, section type, diameter of stud, and web thickness were investigated. Based on the test, hysteretic response, skeleton curves, failure mode, stiffness degradation, ductility, and energy dissipation were discussed. Results show the following: (1) Composite beams have favorable seismic performance, the displacement ductility ratio ranged from 2.5 to 8.75, whereas the maximum equivalent viscous damping ratio ranged from 0.219 to 0.470. (2) The higher the degree of shear connection, longitudinal reinforcement, and transverse reinforcement, the plumper the hysteretic curve and the greater the bearing and energy dissipation capacity. The ductility of composite beam increased as the longitudinal reinforcement ratio increased. The stiffness degradation and residual deformation were less effected by other parameters. (3) Findings suggest that the transverse reinforcement ratio ranged from 0.4% to 0.8%, the positive shear connection degree should be greater than 1, and the spacing of stud in the negative moment region should not be larger than that in the positive moment region. To ensure welding quality and convenient construction, a large diameter of stud should be applied in practical engineering. Moreover, when the girder is welded by a thin web, transverse diaphragm plate and vertical reinforced rib should be added in the steel girder if these areas are heavily loaded. (C) 2018 Elsevier Ltd. All rights reserved.
摘要：
The classical theory of heat conduction (Fourier theory) predicts an infinite speed for thermal disturbance propagation, which is physically unrealistic. By extending the classical Fourier heat conduction and Fick's diffusion, this paper presents a hyperbolic diffusion law with different phase lags of thermal and moisture fluxes to simulate coupled heat-moisture diffusion-propagation behavior. Transient hygrothermal and elastic response of an infinitely long cylinder subjected to sudden hygrothermal loadings at the surface is studied. By using Laplace transform and decoupling technique, a closed form solution of temperature, moisture, displacements and stresses is determined. The analytical results show that the thermal and moisture relaxation times or phase lags of heat and moisture fluxes play a significant role in the early stage of transient response after heat/moisture shock. The classical results corresponding to vanishing phase lags can be recovered from the present ones. For non-vanishing phase lags, hygrothermal waves have finite propagation speeds. Numerical results are calculated and displayed graphically to show the influence of the phase lags of heat and moisture fluxes on transient hygrothermoelastic fields. A comparison between classic model and hyperbolic hygrothermal coupling model is given. Based on the non Fourier heat conduction and non-Fick diffusion, some shortcomings induced by the classical Fourier's and Fick's laws can be effectively avoided. (C) 2018 Elsevier Ltd. All rights reserved.
作者：
Li Wen-bin;Pan Qing-lin;Xiao Yan-ping;He Yun-bin;Liu Xiao-yan
期刊：
Journal of Central South University of Technology,2011年(2):279-284 ISSN：1005-9784
通讯作者：
Pan, QL
作者机构：
[Li Wen-bin; Pan Qing-lin; Xiao Yan-ping; He Yun-bin; Liu Xiao-yan] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Peoples R China.;[Li Wen-bin] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Pan, QL ] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Peoples R China.;Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Peoples R China.
关键词：
Al-Zn-Cu-Mg-Sc-Zr alloy;retrogression and re-aging treatment;microstructure;mechanical properties;stress corrosion cracking
摘要：
The mechanical properties and stress corrosion cracking (SCC) resistance of an Al-Zn-Cu-Mg-Sc-Zr alloy under different aging conditions were investigated. The dependence of microstructure and mechanical properties on aging parameters was evaluated by tensile test, hardness test and conductivity measurement. The results show that for the alloys with retrogression and re-aging treatment (RRA), the conductivity increases with the retrogression time and temperature, while the tensile strength decreases. The transmission electron microscopy (TEM) results show that the precipitates η(MgZn2) at grain boundary aggregate apparently with retrogression time and the precipitates inside the matrix exhibit the similar distribution to T6 temper, which comprises fine GP zones, large η′(MgZn2) and η(MgZn2) phases. According to the mechanical properties and microstructure observations, the optimal RRA regime is recommended to be 120 °C, 24 h + 180 °C, 30 min + 120 °C, 24 h. The strength level of the alloy after the optimum RRA treatment is similar to that in T6 condition and the SCC resistance is improved obviously in contrast to T6 condition.
作者机构：
[Qiu, Zhenfeng; Cao, Ting; Wang, Junjie] Chongqing Jiaotong Univ, Key Lab Hydraul & Waterway Engn, Minist Educ, Chongqing 400074, Peoples R China.;[Qiu, Zhenfeng; Wang, Junjie] Chongqing Jiaotong Univ, Natl Engn Res Ctr Inland Waterway Regulat, Chongqing 400074, Peoples R China.;[Cao, Ting; Li, Yongsuo] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.;[Chen, Yulong] Tsinghua Univ, State Key Lab Hydrosci & Engn, Beijing 100084, Peoples R China.
通讯机构：
[Qiu, ZF; Cao, T; Wang, JJ] Chongqing Jiaotong Univ, Key Lab Hydraul & Waterway Engn, Minist Educ, Chongqing 400074, Peoples R China.;[Qiu, ZF; Wang, JJ] Chongqing Jiaotong Univ, Natl Engn Res Ctr Inland Waterway Regulat, Chongqing 400074, Peoples R China.;[Cao, T; Li, YS] Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.;[Chen, Yulong] Tsinghua Univ, State Key Lab Hydrosci & Engn, Beijing 100084, Peoples R China.
关键词：
sandstone and mudstone particles;rheological deformation;segmented rheological model;rheological limit strain;rheological test
摘要：
A mixture of sandstone and mudstone particles is often used as the main filling material for many agriculture-related and civil engineering projects, including rock-fill dams and foundations. The long-term rheological deformation experienced by rock-fill dams and foundations filled with this mixture is much bigger than that of coarse-grained and cohesive soils, due to the deterioration and softening of the mudstone particles. This study focuses on the rheological deformation of a sandstone-mudstone particle mixture, prepared by mixing sandstone and mudstone particles, based on the content by weight of four mudstone particle types. Confined uniaxial compression tests were performed to test the rheological deformation of 24 samples of the mixture, and a stress-strain curve was obtained for each test. On the basis of compression curves, the rheological process of the mixture was divided into four phases: linear, attenuation rheological, secondary attenuation rheological and stable phases. The three defining features of the curve, namely the rheological attenuation factors, attenuation rheology critical strain and limited rheological strain, were then determined and modeled. A segmented rheological model was then proposed, based on a modified attenuation rheological constitutive model for coarse-grained soil. The modelled results compared well with the experimental data, and the modelled compression-curve prediction was able to describe the two-stage attenuation rheology features (attenuation rheological and secondary attenuation rheological phases) of the sandstone-mudstone particle mixture.
作者：
Liu Xi-ling*;Li Xi-bing;Hong Liang;Yin Tu-bing;Rao Meng
期刊：
Journal of Central South University,2015年(9):3571-3577 ISSN：2095-2899
通讯作者：
Liu Xi-ling
作者机构：
[Yin Tu-bing; Liu Xi-ling; Li Xi-bing; Rao Meng] Cent S Univ, Sch Resources & Safety Engn, Changsha 410083, Peoples R China.;[Liu Xi-ling] Univ British Columbia, Norman B Keevil Inst Min Engn, Vancouver, BC V6T 1Z4, Canada.;[Hong Liang] Hunan City Univ, Sch Civil Engn, Yiyang 413049, Peoples R China.
通讯机构：
[Liu Xi-ling] Cent S Univ, Sch Resources & Safety Engn, Changsha 410083, Peoples R China.
摘要：
Acoustic emission tests were performed using a split Hopkinson pressure bar system (SHPB) on 50-mm-diameter bars of granite, limestone, sandstone and skarn. The results show that the amplitude distribution of hits is not well centralized around 50 dB, and that some hits with large amplitudes, usually larger than 70 dB, occur in the early stages of each test, which is different from the findings from static and low-loading-rate tests. Furthermore, the dominant frequency range of the recorded acoustic emission waveforms is between 300 kHz and 500 kHz, and frequency components higher than 500 kHz are not significant. The hit with the largest values of amplitude, counts, signal strength, and absolute energy in each test, displays a waveform with similar frequency characteristics and greater correlation with the waveform obtained from the elastic input bar of the split Hopkinson pressure bar system compared with the waveforms of the other hits. This indicates that the hit with the largest values of amplitude, counts, signal strength, and absolute energy is generated by elastic wave propagation instead of fracture within the rock specimen.
期刊：
Journal of Central South University,2016年(2):470-478 ISSN：2095-2899
通讯作者：
Cao Guo-hui
作者机构：
[Cao Guo-hui; Zhang Kai] Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.;[Hu Jia-xing] Hunan Univ, Coll Civil Engn, Changsha 410082, Peoples R China.
通讯机构：
[Cao Guo-hui] Hunan City Univ, Coll Civil Engn, Yiyang 413000, Peoples R China.
关键词：
prestress;relaxation loss;shrinkage and creep;theoretical analysis;calculation model
摘要：
The calculation model for the relaxation loss of concrete mentioned in the Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts (JTG D62—2004) was modified according to experimental data. Time-varying relaxation loss was considered in the new model. Moreover, prestressed reinforcement with varying lengths (caused by the shrinkage and creep of concrete) might influence the final values and the time-varying function of the forecast relaxation loss. Hence, the effects of concrete shrinkage and creep were considered when calculating prestress loss, which reflected the coupling relation between these effects and relaxation loss in concrete. Hence, the forecast relaxation loss of prestressed reinforcement under the effects of different initial stress levels at any time point can be calculated using the modified model. To simplify the calculation, the integral expression of the model can be changed into an algebraic equation. The accuracy of the result is related to the division of the periods within the ending time of deriving the final value of the relaxation loss of prestressed reinforcement. When the time division is reasonable, result accuracy is high. The modified model works excellently according to the comparison of the test results. The calculation result of the modified model mainly reflects the prestress loss values of prestressed reinforcement at each time point, which confirms that adopting the finding in practical applications is reasonable.
