检索结果-南通市图书馆

Dynamic response analysis of a multiple-beam structure subjected to a moving load

在线全文

学校读者我要写书评

暂无评论

Earthquake engineering and engineering Vibration 2022年第3期21卷 769-784页

作者： Zhang Yuntai Jiang Lizhong Zhou Wangbao Liu Shaohui Feng Yulin Liu Xiang Lai Zhipeng school of civil engineering Central South UniversityChangsha 410075China National engineering Laboratory for High Speed Railway Construction Changsha 410075China school of civil engineering and architecture East China Jiaotong UniversityNanchang 330013China

In this study,the dynamic response of an elastically connected multi-beam structure subjected to a moving load with elastic boundary conditions is investigated.The boundary conditions and properties of each beam vary,and the difficulty of solving the motion equation is reduced by using a Fourier series plus three special transformations.By examining a high-speed railway(HSR)with mixed boundary conditions,the rationality for the newly proposed method is verified,the difference in simulated multiple-beam models with different beam numbers is explored,and the influence of material parameters and load speed on the dynamic response of multiple-beam structures is examined.Results suggest that the number of beams in the model should be as close to the actual beam number as possible.Models with an appropriate beam number can be used to describe in detail the dynamic response of the structure.Neglecting the track-structure can overestimate the resonant speed of a high-speed railway,simply-supported beam bridge.The effective interval of foundation stiffness(EIFS)can provide a reference for future engineering designs.

关键词： multiple-beam dynamic analysis moving load mixed boundary conditions

Experimental study using the dilution incubation method to assess water biostability

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2014年第10期26卷 1994-2000页

作者： Qiuhua Wang Tao Tao Kunlun Xin College of Environmental Science and engineering Tongji University school of civil engineering and architecture East China Jiaotong University

Water biostability is of particular concern to water supply as a major limiting factor for heterotrophic bacterial growth in water distribution systems. This study focused on bacterial growth dynamics in the series dilution of water samples with TOC（total organic carbon） values determined beforehand. The results showed that the specific growth rate of Pseudomonas fluorescens P17 varied dramatically and irregularly with TOC value when TOC concentrations were low enough during the initial periods of incubation under given conditions. According to this relationship between bacterial growth rate and TOC, a dilution incubation method was designed for the study of water biostability. With the method under a given condition, a turning-point TOC value was found at a relatively fixed point in the curve between bacterial growth rate and TOC of water sample, and the variation of growth rate had different characteristics below the turning-point TOC value relative to that over this value. A turning-point TOC value similarly existed in all experiments not only with tap water, but also with acetate and mixed solutions. And in the dilution incubation method study, the affections were analyzed by condition factors such as inoculum amount,incubation time and nature of the organic carbon source. In very low organic carbon water environments, the variation characteristics of bacterial growth rate will be useful to further understand the meaning of water biostability.

关键词： Water biostability Heterotrophic bacteria Bacterial growth rate Dilution incubation method Total growth organic carbon

砂浆层离缝对高速铁路轨道-桥梁系统自振频率的影响分析

在线全文

学校读者我要写书评

暂无评论

Journal of Central South university 2022年第8期29卷 2807-2819页

作者：刘韶辉蒋丽忠周旺保冯玉林 school of civil engineering Central South UniversityChangsha 410075China National engineering Research Center of High-speed Railway Construction Technology Changsha 410075China School of Civil Engineering and Architecture East China Jiaotong University Nanchang 33013China

在哈密顿原理的基础上,推导综合考虑剪切变形、层间脱空影响的轨道-桥梁系统自由振动控制微分方程及边界条件,提出轨道-桥梁系统自振频率计算方法。基于本文所提计算方法,讨论轨道-桥梁系统弯曲刚度、砂浆层竖向、纵向刚度、脱空位置以... 详细信息

在哈密顿原理的基础上,推导综合考虑剪切变形、层间脱空影响的轨道-桥梁系统自由振动控制微分方程及边界条件,提出轨道-桥梁系统自振频率计算方法。基于本文所提计算方法,讨论轨道-桥梁系统弯曲刚度、砂浆层竖向、纵向刚度、脱空位置以及脱空长度对轨道-桥梁系统自振频率的影响规律。研究结果表明:轨道-桥梁系统固有频率对桥梁层抗弯刚度变化更为敏感;砂浆层纵向刚度和离缝位置变化对轨道-桥梁系统自振频率影响不明显,层间竖向刚度对系统自振频率影响显著;脱空长度变化对轨道-桥梁系统4-5阶固有频率影响更明显,受脱空影响的轨道-桥梁系统自振频率范围随脱空长度增大而增大。

关键词：剪切变形轨道-桥梁系统砂浆层离缝自振频率

Ion Transport and Microstructure of Sandwich Cementitious Materials Exposed to Chloride Environment

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of Technology(Materials Science) 2015年第6期30卷 1274-1278页

作者：王信刚 WANG Kai WANG Rui XIE Tao HUANG Jie school of civil engineering and architecture Nanchang University school of civil engineering and architecture East China Jiaotong University Arts and Design College Nanchang University

Ion transport of sandwich cementitious materials（SCM） exposed to chloride environment was investigated by accelerated diffusion method and natural diffusion method. Pore structure and micromorphology of SCM were investigated by MIP and SEM-EDS. In comparison with the monolayer structural high performance concrete（HPC）, conductive charge for 6 hours, chloride diffusion coefficient, and apparent chloride diffusion coeffi cient of SCM were decreased by 30%-40%, two orders of magnitude and 40%-50%, respectively. Pore structure of ultra low ion permeability cementitious materials（ULIPCM） prepared for the facesheet is superior to that of HPC prepared for the core. As for porosity, the most probable pore radius, the content of pores with radius 50 nm and the surface area of pores, the order is ULIPCM

关键词： sandwich ion transport pore structure micromorphology

Effect of Oils on SBS Modified Asphalt:Rheological Characteristics and Oxidation Aging

在线全文

学校读者我要写书评

暂无评论

Journal of Renewable Materials 2023年第3期11卷 1339-1351页

作者： Jing Xu Yuquan Yao Kai Zhang Jiangang Yang Jie Gao Jian Zhou Jiangxi Transportation Institute Co. Ltd.Nanchang330200China school of civil engineering and architecture East China Jiaotong UniversityNanchang330013China school of Highway Chang’an UniversityXi’an710064China

This study focuses on the effect of oils on rheology and oxidation aging of Styrene-Butadiene-Styrene modified asphalt(SBSMA)in the long term,after reducing one low-temperature Performance Grade(PG)of SBSMA by incorporating oils.Two oils,including corn-based bio-oil and re-refined engine oil bottom(REOB),were selected to enhance the low-temperature performance of SBSMA.All samples were subjected to Rolling Thin Film Oven(RTFO)aging and 20-h as well as 40-h Pressure Aging Vessel(PAV20 and PAV40)aging,prior to multiple stress creep recovery(MSCR),frequency sweep and Flourier transform infrared spectroscopy(FTIR)scanning.A good high-temperature performance of oil/SBS modified asphalt blends was reflected in MSCR and PG results,meanwhile non-recoverable creep compliance(Jnr)and recovery(R)were found to share a highly correlated relationship during aging progress.In addition,Glover–Rowe(G–R)parameter and phase angle master curves suggest that the improvement of cracking property mainly came from the softening effect of oils.Adding oils into SBSMA was observed to increase oxidation kinetics,but the blends with oils still exhibited better anti-oxidation aging than the base binder,mainly due to the SBS addition.Bio-oil exhibited an effect of relieving age hardening susceptibility of SBSMA.

关键词： Oil aging rheology oxidation kinetics cracking resistance

A new method to forecast multi-time scale load of natural gas based on augmentation data-machine learning model

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical engineering 2022年第8期35卷 166-175页

作者： Denglong Ma Ruitao Wu Zekang Li Kang Cen Jianmin Gao Zaoxiao Zhang school of Mechanical engineering Xi’an Jiaotong UniversityXi’an 710049China school of civil engineering and architecture Southwest Petroleum UniversityChengdu 610500China school of Chemical engineering and Technology Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory for Manufacturing System engineering Xi’an Jiaotong UniversityXi’an 710049China

Gas load forecasting is important for the economic and reliable operation of the city gas transmission and distribution system.In this paper,a nonlinear autoregressive model(NARX)with exogenous inputs,support vector machine(SVM),Gaussian process regression(GPR)and ensemble tree model(ETREE)were used to predict and compare the gas load based on the gas load data in a certain region for past 3 years.The results showed that the prediction errors for most of days were higher than 10%.Further,simulation data were generated by considering the gas load variation trend,which was then combined with historical data to form the augmentation data set to train the model.The test results indicated that the prediction error of daily gas load in one year reduced to below 7%with a machine learning prediction method based on augmentation data.In addition,the model based on augmentation data set still performed better than original data in predicting the monthly gas load in last year as well as daily gas load in last month and week.Therefore,the method based on augmentation data proposed in this paper is a potentially good tool to forecast natural gas load.

关键词： Natural gas Machine learning Prediction Neural network Augmentation data

基于Cosserat连续体框架罚函数偶应力有限元法的固体结构弹塑性分析

在线全文

学校读者我要写书评

暂无评论

Journal of Central South university 2022年第4期29卷 1320-1331页

作者：王冬勇陈曦姜升彬齐吉琳彭丽云 school of civil and Transportation engineering Beijing University of Civil Engineering and ArchitectureBeijing 100044China Key Laboratory of Urban Underground engineering of Ministry of Education Beijing Jiaotong UniversityBeijing 100044China

为了降低直接偶应力有限元方法的复杂度,在Cosserat连续体框架下通过对C1连续性进行松弛来获得其近似解,建立基于罚函数的偶应力有限元方法(简称PcouFEM),并通过三个数值算例对PcouFEM的性能进行了研究。对于平面应变条件下的圆孔应力... 详细信息

为了降低直接偶应力有限元方法的复杂度,在Cosserat连续体框架下通过对C1连续性进行松弛来获得其近似解,建立基于罚函数的偶应力有限元方法(简称PcouFEM),并通过三个数值算例对PcouFEM的性能进行了研究。对于平面应变条件下的圆孔应力集中问题,研究发现当罚因子不小于经典连续体剪切模量的5倍时(即G_(c)≥5G),基于缩减积分PcouFEM计算获得的应力集中因子与解析解基本吻合;对于单轴压缩试验应变局部化分析,通过应用PcouFEM可以减弱甚至消除与常规FEM相关的网格依赖性问题,且从数值精度的角度建议取值为5G≤G_(c)≤10G;对于通过刚性条形基础承受偏心载荷的土质边坡,研究发现土坡剪切带模拟中的网格依赖问题同样可以通过应用PcouFEM得到较大缓解。

关键词：偶应力理论 Cosserat理论罚因子应力集中应变局部化

Theory and Application of Natural-Based Wavelet Method

在线全文

学校读者我要写书评

暂无评论

Journal of Harbin Institute of Technology(New Series) 2019年第6期26卷 86-90页

作者： Yanhua Cao Mengcheng Chen Baogen Xu school of Science East China Jiaotong UniversityNanchang 330013China Institute of architecture and civil engineering East China Jiaotong UniversityNanchang 330013China

Wavelet method is often used in analyzing trend and period of time sequence. When using wavelet method one serious problem is different chosen wavelet basis and scale would lead to different results. Sometimes, the results vary greatly. To overcome this problem and to improve the accuracy and efficiency, a new method denoted by Natural-based Wavelet Method is introduced and extended. It can be proved that the proposed method in fact is a special class of discrete wavelet. At first, two numerical examples are designed to show the capacity of the novel method. Second, this method is applied to a precipitation series. According to wavelet analysis and short-range precipitation prediction, this precipitation exists a faintly increasing trend. Through the analysis, the studied precipitation has two major periods: 11 and 41 years. The results validate that the Natural-based Wavelet Method used in application of multi-complicated observed data is suitable. It is easy to write the source code of the proposed method. When new information appears, new information can be easily added into the original sequence, this is another advantage of the proposed method.

关键词： natural-based wavelet method long-time precipitation sequence short-range precipitation time sequence

Study of the wall adhesive tensile contact of moist iron ore bulk solids

在线全文

学校读者我要写书评

暂无评论

Particuology 2020年第3期18卷 67-75页

作者： Tao Fang Wei Chen Jens Plinke Craig Wheeler Alan Roberts school of civil engineering East China Jiaotong UniversityNanchang 330013China school of engineering The University of NewcastleCallaghan 2308Australia

The adhesive tensile stress between moist bulk iron ore solids and wall surfaces are critical to control and avoid blockage in large throughput material handling plants.In this study,an experimental system was designed to investigate the adhesive tensile contact between a range of iron ore materials and wall lining specimens.The contact mechanism between the material specimen and the wall surface was initially characterised.The experimental results indicated that the adhesive tensile stress is dependent on both the moisture content and the applied major consolidation stress,with the former exhibiting more significant contribution to increasing the magnitude of stress.The surface roughness of the wall showed a negligible effect in determining the adhesive tensile stress.Additionally,the iron ore sample with a higher fines content was observed to be able to achieve a higher adhesive tensile stress compared to the coarse samples.Consequently,the insights resulting from the study demonstrated practical applicability through measures such as blending and/or beneficiation,which reduce the adhesive tensile stress and minimise blockages.

关键词： Wet sticky material Adhesive tensile stress Wall linings Liquid bridge force Capillary stress Soil texture