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Finite element modeling of cable sliding and its effect on dynamic response of cable-supported truss

Yujie YU, Zhihua CHEN, Renzhang YAN

《结构与土木工程前沿（英文）》 2019年 第13卷 第5期   页码 1227-1242 doi: 10.1007/s11709-019-0551-5

摘要： The cable system of cable-supported structures usually bears high tension forces, and clip joints may fail to resist cable sliding in cases of earthquake excitations or sudden cable breaks. A analytical method that considers the dynamic cable sliding effect is proposed in this paper. Cable sliding behaviors and the resultant dynamic responses are solved by combining the vector form intrinsic finite element framework with cable force redistribution calculations that consider joint frictions. The cable sliding effect and the frictional tension loss are solved with the original length method that uses cable length and the original length relations. Then, the balanced tension distributions are calculated after frictional sliding. The proposed analytical method is achieved within MATLAB and applied to simulate the dynamic response of a cable-supported plane truss under seismic excitation and sudden cable break. During seismic excitations, the cable sliding behavior in the cable-supported truss have an averaging effect on the oscillation magnitudes, but it also magnifies the internal force response in the upper truss structure. The slidable cable joints can greatly reduce the ability of a cable system to resist sudden cable breaks, while strong friction resistances at the cable-strut joints can help retain internal forces.

关键词： sliding cable     explicit solution framework     original length method     seismic response     cable rupture    

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The defect-length effect in corrosion detection with magnetic method for bridge cables

Qiwei ZHANG, Rongya XIN

《结构与土木工程前沿（英文）》 2018年 第12卷 第4期   页码 662-671 doi: 10.1007/s11709-018-0512-4

摘要：

Quantitative evaluation of the steel corrosion in cables is significant for the safe operation of cable-supported bridges. The magnetic flux (MF) examination shows great potential to detect the corrosion defect, or loss of metallic cross-sectional area (LMA). An LMA defect in steel cables can be measured accurately when it is longer than a certain length. However, for defects in early stage, where the length of corrosion area is short, the MF examination may produce unacceptable error. In this study, the effect of defect length on the MF examination for corrosion detection of bridge cables is investigated through theoretical analysis and model experiments. An original analytical model to quantify the influence of defect length is proposed based on the equivalent magnetic circuit method. Then, MF examination experiments are performed on a series of cable models with different defect lengths and locations to verify the analytical model. Further, parameter study is conducted based on the proposed analytical model to clarify the mechanism of the defect-length effect. The results show that the area loss caused by short corrosion damage will be underestimated if the defect-length effect is neglected, and this effect can be quantified efficiently with the proposed analytical model.

关键词： bridge cable     corrosion detection     defect length     MF examination     quantitative evaluation    

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一种对工业过程复杂液体进行非接触原态在线实时监测方法 Article

段宁, 降林华, 徐夫元, 张歌

《工程（英文）》 2018年 第4卷 第3期   页码 392-397 doi: 10.1016/j.eng.2018.05.005

摘要：

无法对工业过程大量存在的复杂液体在线实时监测导致资源消耗和污染产生过多的现象十分普遍。本文介绍一种对高强包裹性和高盐多组分液体中目标物质进行非接触原态在线实时监测的方法，该方法的原理是建立液体中目标物质浓度（C）、不同浓度目标物质色空间坐标(L*, a*, b*)  和最大吸收波长（λmax）三者之间的关系，利用最佳波长λT下高精度扫描式检测系统表达的液体光强信息直接测定流动液体中目标物质的瞬时浓度。与传统分析方法和现有在线分析方法不同，这种方法无需对样品进行任何预处理（过滤、稀释、定容、氧化/还原、添加显色剂等），可实现测试样品的原态化在线实时监测。将一家大型电解锰企业陈化液（Fe3+浓度0.5~18 mg•L-1， 锰离子35~39 g•L-1，硫酸铵90~110 g•L-1）胶体化过程中三价铁离子浓度的实测结果与离线实验室测试结果相比，二者相对误差小于2%。

关键词： 复杂液体     原态监测     在线实时     非接触识别    

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以土体应力状态计算边坡安全系数的方法

王国体

《中国工程科学》 2006年 第8卷 第12期   页码 80-84

摘要：

土坡的稳定分析一直是沿着条分法的思路发展的。由于对土体应力状态条件的忽视和条分法本身的缺陷，使得条分法得到的安全系数在工程中的应用面临激烈的挑战。土体不同条件下的应力状态表现为K0效应和变化，它对坡体的安全度影响不可忽视。笔者以考虑土体应力状态为条件，应用土的库伦强度定律和摩尔-库伦准则，推导出平面土坡的安全系数计算公式，与条分法的安全系数对比结果说明这种方法具有概念明确、计算简便、定性可靠的重要特点，可以直接提供于工程应用和参考。

关键词： 侧应力系数K0     初始应力状态     稳定安全系数公式    

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Applying the spectral stochastic finite element method in multiple-random field RC structures

Abbas YAZDANI

《结构与土木工程前沿（英文）》 2022年 第16卷 第4期   页码 434-447 doi: 10.1007/s11709-022-0820-6

摘要： This paper uses the spectral stochastic finite element method (SSFEM) for analyzing reinforced concrete (RC) beam/slab problems. In doing so, it presents a new framework to study how the correlation length of a random field (RF) with uncertain parameters will affect modeling uncertainties and reliability evaluations. It considers: 1) different correlation lengths for uncertainty parameters, and 2) dead and live loads as well as the elasticity moduli of concrete and steel as a multi-dimensional RF in concrete structures. To show the SSFEM’s efficiency in the study of concrete structures and to evaluate the sensitivity of the correlation length effects in evaluating the reliability, two examples of RC beams and slabs have been investigated. According to the results, the RF correlation length is effective in modeling uncertainties and evaluating reliabilities; the longer the correlation length, the greater the dispersion range of the structure response and the higher the failure probability.

关键词： uncertainty     spectral stochastic finite element method     correlation length     reliability assessment     reinforced concrete beam/slab    

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基于TRIZ中需求进化定律的一类原始创新过程研究

檀润华,马建红, 陈子顺,江屏

《中国工程科学》 2008年 第10卷 第11期   页码 52-58

摘要：

需求进化定律是发明问题解决理论（TRIZ）体系中的最新研究成果，在分析这些定律的基础上，提出未来需求预测原理，定义了困难功能元的概念及效应综合方法，形成了从需求预测到困难功能元效应综合实现的一类原始创新过程模型。

关键词： TRIZ     需求进化定律     原始创新     困难功能元     效应综合法     过程模型    

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Acceleration of the particulate organic matter hydrolysis by start-up stage recovery and its original

Yanqing Duan, Aijuan Zhou, Xiuping Yue, Zhichun Zhang, Yanjuan Gao, Yanhong Luo, Xiao Zhang

《环境科学与工程前沿（英文）》 2021年 第15卷 第1期 doi: 10.1007/s11783-020-1304-3

摘要： Abstract • Carbon availability was partially solved by POM recovery and fermentation. • 12% carbon sources were regenerated by fermentation of the entrapped 35% TCOD. • The unique microbial communities facilitated the efficient hydrolysis of the POM. • Considerable economic benefits in aeration power and ECS dosage were anticipated. To address the availability of carbon sources for denitrification, the accelerated hydrolysis of the most abundant but low-availability fraction of particulate organic matter (POM) was investigated. Mesh sieves with different pore sizes were used as primary pretreatment at the start-up-stage of the biological process to separate some POM from the liquid system. The changes in soluble carbohydrates and proteins were monitored to investigate the hydrolysis performance of the sieved POM, with waste activated sludge (WAS) as the control test. The results showed that an average of 35% POM could be entrapped before filtrate mat development. In addition, benefiting from the high polysaccharides concentration, as well as the high availability due to the relatively loose physical structure, a 23% hydrolysis efficiency of POM was obtained, in contrast to that of WAS (3.4%), with a hydrolysis constant of 0.39 h−1. The prominent performance was also attributed to the unique microbial communities having been domesticated at a lower temperature, especially the cellulose-degrading bacteria Paraclostridium and psychrophile Psychrobacter, making up 6.94% and 2.56%, respectively. Furthermore, the potential benefits and application of improved POM hydrolysis by start-up stage recovery via mesh sieves combined with anaerobic fermentation were evaluated, including selective POM entrapment, alleviation of blockage and wear, and a reduction in aeration energy. By the proposed strategy, carbon availability for biological nutrient removal (BNR) processes is anticipated to be improved more economically than that can be achieved by primary clarifier elimination.

关键词： Particulate organic matter (POM)     Hydrolysis     Microbial community     Mass balance    

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Effects of slip length and hydraulic diameter on hydraulic entrance length of microchannels with superhydrophobic

Wenchi GONG, Jun SHEN, Wei DAI, Zeng DENG, Xueqiang DONG, Maoqiong GONG

《能源前沿（英文）》 2020年 第14卷 第1期   页码 127-138 doi: 10.1007/s11708-020-0661-8

摘要： This paper investigated effects of slip length and hydraulic diameter on the hydraulic entrance length of laminar flow in superhydrophobic microchannels. Numerical investigations were performed for square microchannels with Re ranging between 0.1 and 1000. It is found that superhydrophobic microchannels have a longer hydraulic entrance length than that of conventional ones by nearly 26.62% at a low Re. The dimensionless hydraulic entrance length slightly increases with the increasing slip length at approximately Re<10, and does not vary with the hydraulic diameter. A new correlation to predict the entrance length in square microchannels with different slip lengths was developed, which has a satisfying predictive performance with a mean absolute relative deviation of 5.69%. The results not only ascertain the flow characteristics of superhydrophobic microchannels, but also suggest that super hydrophobic microchannels have more significant advantages for heat transfer enhancement at a low Re.

关键词： laminar flow     hydraulic entrance length     super hydrophobic surface     slip length     hydraulic diameter    

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Structural behavior of intermediate length cold-formed steel rack columns with C-stitches

M. ANBARASU, Mahmud ASHRAF

《结构与土木工程前沿（英文）》 2019年 第13卷 第4期   页码 937-949 doi: 10.1007/s11709-019-0528-4

摘要： This article presents an experimental and numerical investigation on the strength and performance of intermediate length rack column sections with C-stitches under axial compression. The test program consisted of 10 axial concentric compression tests on columns with and without C-stitches under pin end conditions for two different geometric lengths. Finite element (FE) models were developed using commercial FE package ABAQUS considering material and geometric nonlinearities as well as initial geometric imperfections. The elastic buckling properties of the section were calculated using readily available linear elastic buckling analysis tools based on Generalized Beam Theory (GBT) and Finite Strip Method (FSM). Obtained FE results were compared with those obtained experimentally, and once verified the developed FE modeling technique was used to carry out a parametric study to examine changes in structural response due to variations in length, depth and spacing of C-stitches. Observed influences of C-stitches on the behavior and resistance of the considered columns were carefully analyzed, and key design aspects are presented herein.

关键词： cold-formed steel columns     C-stitches     intermediate length columns     distortional buckling    

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Association between telomere length and survival in cancer patients: a meta-analysis and review of literature

null

《医学前沿（英文）》 2016年 第10卷 第2期   页码 191-203 doi: 10.1007/s11684-016-0450-2

摘要：

The relationship between telomere length and cancer survival has been widely studied. To gain a deeper insight, we reviewed the published studies. A total of 29 studies evaluated telomere length in the peripheral blood; 22 studies evaluated telomere length in the tumor tissue. First, in the peripheral blood studies, for solid tumor patients with shortened telomere length, the combined hazard ratios (HRs) for mortality and tumor progression were 1.21 (95%CI, 1.10–1.32) and 1.71 (95%CI, 1.37–2.13), respectively. Meanwhile, in hematology malignancy, the combined HRs for mortality and tumor progression were 2.83 (95%CI, 2.14–3.74) and 2.65 (95%CI, 2.18–3.22), respectively. Second, in the studies that use tumor tissue, for patients with shortened telomeres, the combined HRs for mortality and tumor progression were 1.26 (95%CI, 0.95–1.66) and 1.65 (95%CI, 1.26–2.15), respectively. In the studies that calculate the telomere length ratios of tumor tissue to adjacent normal mucosa, for patients with lower telomere length ratios, the combined HRs were 0.66 (95%CI, 0.53–0.83) and 0.74 (95%CI, 0.41–1.32) for mortality and tumor progression, respectively. In conclusion, shortened telomere in peripheral blood and tumor tissue might indicate poor survival for cancer patients. However, by calculating the telomere length ratios of tumor tissue to adjacent normal mucosa, the lower ratio might indicate better survival.

关键词： telomere     survival     cancer     meta-analysis    

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Modelling of dynamic contact length in rail grinding process

null

《机械工程前沿（英文）》 2014年 第9卷 第3期   页码 242-248 doi: 10.1007/s11465-014-0305-y

摘要：

Rails endure frequent dynamic loads from the passing trains for supporting trains and guiding wheels. The accumulated stress concentrations will cause the plastic deformation of rail towards generating corrugations, contact fatigue cracks and also other defects, resulting in more dangerous status even the derailment risks. So the rail grinding technology has been invented with rotating grinding stones pressed on the rail with defects removal. Such rail grinding works are directed by experiences rather than scientifically guidance, lacking of flexible and scientific operating methods. With grinding control unit holding the grinding stones, the rail grinding process has the characteristics not only the surface grinding but also the running railway vehicles. First of all, it’s important to analyze the contact length between the grinding stone and the rail, because the contact length is a critical parameter to measure the grinding capabilities of stones. Moreover, it’s needed to build up models of railway vehicle unit bonded with the grinding stone to represent the rail grinding car. Therefore the theoretical model for contact length is developed based on the geometrical analysis. And the calculating models are improved considering the grinding car’s dynamic behaviors during the grinding process. Eventually, results are obtained based on the models by taking both the operation parameters and the structure parameters into the calculation, which are suitable for revealing the process of rail grinding by combining the grinding mechanism and the railway vehicle systems.

关键词： rail grinding     contact length     dynamic model     Hamiltonian system     grinding stone     rail grinding car    

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Optimization of aero-engine pipeline for avoiding vibration based on length adjustment of straight-line

《机械工程前沿（英文）》 2022年 第17卷 第1期   页码 11-11 doi: 10.1007/s11465-021-0667-x

摘要： In the design and troubleshooting of aero-engine pipeline, the vibration reduction of the pipeline system is often achieved by adjusting the hoop layout, provided that the shape of pipeline remains unchanged. However, in reality, the pipeline system with the best antivibration performance may be obtained only by adjusting the pipeline shape. In this paper, a typical spatial pipeline is taken as the research object, the length of straight-line segment is taken as the design variable, and an innovative optimization method of avoiding vibration of aero-engine pipeline is proposed. The relationship between straight-line segment length and parameters that determine the geometric characteristics of the pipeline, such as the position of key reference points, bending angle, and hoop position, are derived in detail. Based on this, the parametric finite element model of the pipeline system is established. Taking the maximum first-order natural frequency of pipeline as the optimization objective and introducing process constraints and vibration avoidance constraints, the optimization model of the pipeline system is established. The genetic algorithm and the golden section algorithm are selected to solve the optimization model, and the relevant solution procedure is described in detail. Finally, two kinds of pipelines with different total lengths are selected to carry out a case study. Based on the analysis of the influence of straight-line segment length on the vibration characteristics of the pipeline system, the optimization methods developed in this paper are demonstrated. Results show that the developed optimization method can obtain the optimal single value or interval of the straight-line segment length while avoiding the excitation frequency. In addition, the optimization efficiency of the golden section algorithm is remarkably higher than that of the genetic algorithm for length optimization of a single straight-line segment.

关键词： length adjustment     spatial pipeline     aero-engine     vibration avoidance optimization     genetic algorithm     golden section algorithm    

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用考虑置信区间长度影响的最小二乘法拟合S-N曲线

杨晓华,金平,姚卫星

《中国工程科学》 2004年 第6卷 第4期   页码 41-43

摘要：

S-N曲线是用名义应力法预测结构疲劳寿命的基础。基于试验疲劳寿命分散的物理机制，提出了一个S-N曲线试验数据处理的加权最小二乘法，此方法中每组数据的权重与该组数据的置信区间成反比。计算结果表明用考虑置信区间长度影响的最小二乘法拟合得到的S-N曲线比用一般最小二乘法得到的S-N曲线具有更高的可靠度，给出的寿命预测结果也更安全。

关键词： 置信区间     疲劳寿命     最小二乘法     S-N曲线    

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New form of geodetic coordinate system taking two length quantity as coordinate parameters

Yimin SHI, Ziyang ZHU, Yeming FAN

《结构与土木工程前沿（英文）》 2009年 第3卷 第1期   页码 105-110 doi: 10.1007/s11709-009-0014-5

摘要： A new form of geodetic coordinate system based on geodesic coordinates instead of geodetic longitude and latitude was proposed. The vertical and horizontal geodesic coordinates measured with length were defined as coordinate parameters, but the two families of coordinate curves were still meridians and parallel circles. The first fundamental form on the ellipsoidal surface and its three coefficients were deduced by the geodesic coordinate. The formula for the latitudinal scale factor of length for geodetic parallel lines was derived, by which the obtained result conformed to that standard value calculated from geodetic latitude, and it is applicable in the range of 400 km from north to south. Therefore, it lays the foundation for establishing the differential equation and differential relationship based on this type of coordinate parameters; and consequently, it is convenient and accurate enough to operate on the ellipsoidal surface in this new form of geodetic coordinate system.

关键词： geodetic coordinate system     meridian and parallel circle     coordinate parameter     the first fundamental form on the ellipsoidal surface     latitudinal scale factor of length    

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Catheterization via direct cannulation of superior vena cava for a hemodialysis patient with an original

null

《医学前沿（英文）》 2017年 第11卷 第3期   页码 445-448 doi: 10.1007/s11684-017-0520-0

摘要：

Establishing a long-term vascular access in patients exhibiting vascular access exhaustion is challenging. In this study, we reported a case of a direct catheterization in the superior vena cava of a hemodialysis patient with vascular access exhaustion and original dysfunctional catheter inserted via the left internal jugular vein. The direct catheterization was performed with cuffed tunnel catheter (CUFF) and guided by digital subtraction angiography (DSA) and multidetector computed tomography venography (MDCTV). The DSA and MDCTV results revealed an occlusion in the right innominate vein and thromboses in the left innominate, right internal jugular, subclavian, and femoral veins. The distal end of the superior vena cava was localized clearly by the original CUFF under DSA. Directed at the distal end of the superior vena cava, a 0.5-cm secondary puncture was introduced below the lateral head of the sternocleidomastoid muscle via the right neck area. This study is one of the few reports regarding direct catheterization of CUFF via the superior vena cava of a patient with vascular access exhaustion and CUFF dysfunction on the left internal jugular vein. We believe that our study can provide a new alternative for inserting central venous catheter for such patient.

关键词： superior vena cava     intervention     vascular access exhaustion     catheterization     tunneled cuffed hemodialysis catheter    

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标题 作者 时间 类型 操作

Finite element modeling of cable sliding and its effect on dynamic response of cable-supported truss

Yujie YU, Zhihua CHEN, Renzhang YAN

期刊论文

The defect-length effect in corrosion detection with magnetic method for bridge cables

Qiwei ZHANG, Rongya XIN

期刊论文

一种对工业过程复杂液体进行非接触原态在线实时监测方法

段宁, 降林华, 徐夫元, 张歌

期刊论文

以土体应力状态计算边坡安全系数的方法

王国体

期刊论文

Applying the spectral stochastic finite element method in multiple-random field RC structures

Abbas YAZDANI

期刊论文

基于TRIZ中需求进化定律的一类原始创新过程研究

檀润华,马建红, 陈子顺,江屏

期刊论文

Acceleration of the particulate organic matter hydrolysis by start-up stage recovery and its original

Yanqing Duan, Aijuan Zhou, Xiuping Yue, Zhichun Zhang, Yanjuan Gao, Yanhong Luo, Xiao Zhang

期刊论文

Effects of slip length and hydraulic diameter on hydraulic entrance length of microchannels with superhydrophobic

Wenchi GONG, Jun SHEN, Wei DAI, Zeng DENG, Xueqiang DONG, Maoqiong GONG

期刊论文

Structural behavior of intermediate length cold-formed steel rack columns with C-stitches

M. ANBARASU, Mahmud ASHRAF

期刊论文

Association between telomere length and survival in cancer patients: a meta-analysis and review of literature

null

期刊论文

Modelling of dynamic contact length in rail grinding process

null

期刊论文

Optimization of aero-engine pipeline for avoiding vibration based on length adjustment of straight-line

期刊论文

用考虑置信区间长度影响的最小二乘法拟合S-N曲线

杨晓华,金平,姚卫星

期刊论文

New form of geodetic coordinate system taking two length quantity as coordinate parameters

Yimin SHI, Ziyang ZHU, Yeming FAN

期刊论文

Catheterization via direct cannulation of superior vena cava for a hemodialysis patient with an original

null

期刊论文