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Elevated temperature creep model of parallel wire strands

《结构与土木工程前沿（英文）》   页码 1060-1071 doi: 10.1007/s11709-023-0981-y

摘要： Parallel wire strands (PWSs), which are widely used in prestressed steel structures, are typically in high-stress states. Under fire conditions, significant creep effects occur, reducing the prestress and influencing the mechanical behavior of PWSs. As there is no existing approach to analyze their creep behavior, this study experimentally investigated the elevated temperature creep model of PWSs. A charge-coupled camera system was incorporated to accurately obtain the deformation of the specimen during the elevated temperature creep test. It was concluded that the temperature level had a more significant effect on the creep strain than the stress level, and 450 °C was the key segment point where the creep rate varied significantly. By comparing the elevated temperature creep test results for PWSs and steel strands, it was found that the creep strain of PWSs was lower than that of steel strands at the same temperature and stress levels. The parameters in the general empirical formula, the Bailey–Norton model, and the composite time-hardening model were fitted based on the experimental results. By evaluating the accuracy and form of the models, the composite time-hardening model, which can simultaneously consider temperature, stress, and time, is recommended for use in the fire-resistance design of pre-tensioned structures with PWSs.

关键词： parallel wire strands     experimental study     elevated temperature creep model    

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Hysteretic behavior of cambered surface steel tube damper: Theoretical and experimental research

《结构与土木工程前沿（英文）》 2023年 第17卷 第4期   页码 606-624 doi: 10.1007/s11709-023-0925-6

摘要： A novel cambered surface steel tube damper (CSTD) with a cambered surface steel tube and two concave connecting plates is proposed herein. The steel tube is the main energy dissipation component and comprises a weakened segment in the middle, a transition segment, and an embedded segment. It is believed that during an earthquake, the middle weakened segment of the CSTD will be damaged, whereas the reliability of the end connection is ensured. Theoretical and experimental studies are conducted to verify the effectiveness of the proposed CSTD. Formulas for the initial stiffness and yield force of the CSTD are proposed. Subsequently, two CSTD specimens with different steel tube thicknesses are fabricated and tested under cyclic quasi-static loads. The result shows that the CSTD yields a stable hysteretic response and affords excellent energy dissipation. A parametric study is conducted to investigate the effects of the steel tube height, diameter, and thickness on the seismic performance of the CSTD. Compared with equal-stiffness design steel tube dampers, the CSTD exhibits better energy dissipation performance, more stable hysteretic response, and better uniformity in plastic deformation distributions.

关键词： cambered surface steel tube damper     energy dissipation capacity     finite element model     hysteretic performance     parametric study    

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Geometrical nonlinear deformation model and its experimental study on bimorph giant magnetostrictive

LIU Wei, JIA Zhenyuan, WANG Fuji, ZHANG Yongshun, GUO Dongming

《机械工程前沿（英文）》 2008年 第3卷 第3期   页码 313-317 doi: 10.1007/s11465-008-0048-8

摘要： The geometrical nonlinearity of a giant magnetostrictive thin film (GMF) can be clearly detected under the magnetostriction effect. Thus, using geometrical linear elastic theory to describe the strain, stress, and constitutive relationship of GMF is inaccurate. According to nonlinear elastic theory, a nonlinear deformation model of the bimorph GMF is established based on assumptions that the magnetostriction effect is equivalent to the effect of body force loaded on the GMF. With Taylor series method, the numerical solution is deduced. Experiments on TbDyFe/Polyimide (PI)/SmFe and TbDyFe/Cu/SmFe are then conducted to verify the proposed model, respectively. Results indicate that the nonlinear deflection curve model is in good conformity with the experimental data.

关键词： magnetostrictive     nonlinear     magnetostriction     inaccurate     geometrical nonlinearity    

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Experimental and computational validation of a scaled train tunnel model using modal analysis

Janice B. D’SOUZA, Sangarapillai KANAPATHIPILLAI

《机械工程前沿（英文）》 2013年 第8卷 第4期   页码 420-428 doi: 10.1007/s11465-013-0281-7

摘要：

Acoustic engineers are faced with the challenge of minimising reverberation time in their designs so as to contribute to the health and well-being of those traveling by train and those on the platforms. Although the problem is easy to identify, it is not as simple to solve. The acoustical environment of a train tunnel is complex, with a variety of noise contributing factors such as train announcements, speech of commuters, ventilation systems, electrical equipment and wheel and rail noise. As a result, there is some difficulty in modeling the complete acoustic environment with computational or acoustic first principles. In this study, an experimental rig was constructed to model the acoustic behavior within a tunnel. The modal properties for the 300 Hz to 1500 Hz range, including resonances and mode shapes were identified and were shown to successfully correspond to theoretical results and a computational model created in COMSOL using Finite Element Analysis.

关键词： reverberation time     acoustic environment     modal properties     resonances    

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Experimental study on the establishment and maintenance of brain death model with pigs

ZHANG Shuijun, SHI Jihua, ZHAI Wenlong, SONG Yan, CHEN Shi

《医学前沿（英文）》 2007年 第1卷 第2期   页码 161-166 doi: 10.1007/s11684-007-0030-6

摘要： It remains controversial that after the transplantation of using grafts from brain-dead donors, organs injury and rejection can influence the effects of transplantation. This study sought to explore methods of establishing a stable brain death (BD) model using Bama mini pigs and to maintain the brain-dead state for a comparatively long period to provide a model for investigating changes in brain death. Sixteen anesthetized Bama mini pigs were randomized into a control group ( = 5) and a BD group ( = 11). Intracranial pressure (ICP) was increased in a modified, slow, and intermittent way to establish BD. Respiration and circulation were sustained during the brain-dead state. Hemodynamic changes were monitored during the experiment. In the BD group, 10 pigs met the requirements for brain death and 1 died of cardiopulmonary complications following an increase in ICP. Brain death was maintained for more than 48 hours with artificial life support. During the experiment, the heart rate and blood pressure showed characteristic changes due to increased ICP. Prior to BD being established, a tic reaction inevitably occurred. We used an improved method of increasing ICP to establish a stable BD model. The BD state could be maintained for more than 48 hours with effective respiratory and circulatory support. Disappearance of the tic reaction was considered to be one of the verified indexes for BD via encephalic pressure increase.

关键词： BD     control     Hemodynamic     cardiopulmonary     modified    

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大跨径钢桥桥道系协同作用试验模型研究

夏国星,钱振东,陈春,刘龑

《中国工程科学》 2012年 第14卷 第5期   页码 96-100

摘要：

建立了考虑整桥变形的局部梁段模型，对钢桥面铺装在整桥及车载作用下的应力进行了计算，得到整桥变形的影响系数为1.17。建立初拟的两种协同作用试验方案的有限元模型，以局部梁段模型中铺装的最大应力应变值为参考值，对两种协同作用试验方案中相关结构参数进行了修正；在此基础上，为保证设计的协同作用试验模型与原型的一致性，将修正后的试验模型与局部梁段模型在控制点位应力值进行了对比；最终得到大跨径钢桥桥道系协同作用试验模型。研究成果可为钢桥面铺装室内试验模型的设计提供理论依据。

关键词： 协同作用     试验模型     大跨径钢桥桥道系    

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Numerical and experimental research of the characteristics of concentration solar cells

Zilong WANG, Hua ZHANG, Binlin DOU, Weidong WU, Guanhua ZHANG

《能源前沿（英文）》 2021年 第15卷 第2期   页码 279-291 doi: 10.1007/s11708-019-0637-8

摘要： The development of automatic tracking solar concentrator photovoltaic systems is currently attracting growing interest. High concentration photovoltaic systems (HCPVs) combining triple-junction InGaP/lnGaAs/Ge solar cells with a concentrator provide high conversion efficiencies. The mathematical model for triple-junction solar cells, having a higher efficiency and superior temperature characteristics, was established based on the one-diode equivalent circuit cell model. A paraboloidal concentrator with a secondary optic system and a concentration ratio in the range of 100X–150X along with a sun tracking system was developed in this study. The GaInP/GalnAs/Ge triple-junction solar cell, produced by AZUR SPACE Solar Power, was also used in this study. The solar cells produced by Shanghai Solar Youth Energy (SY) and Shenzhen Yinshengsheng Technology Co. Ltd. (YXS) were used as comparison samples in a further comparative study at different concentration ratios (200X–1000X). A detailed analysis on the factors that influence the electrical output characteristics of the InGaP/lnGaAs/Ge solar cell was conducted with a dish-style concentrating photovoltaic system. The results show that the short-circuit current ( ) and the open-circuit voltage ( ) of multi-junction solar cells increases with the increasing concentration ratio, while the cell efficiency ( ) of the solar cells increases first and then decreases with increasing concentration ratio. With increasing solar cell temperature, increases, while and decrease. A comparison of the experimental and simulation results indicate that the maximum root mean square error is less than 10%, which provides a certain theoretical basis for the study of the characteristics of triple-junction solar cell that can be applied in the analysis and discussion regarding the influence of the relevant parameters on the performance of high concentration photovoltaic systems.

关键词： concentration     three-junction solar cell     mathematical model     electrical properties     solar energy    

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Analytical study on damping performances of magnetorheological grease damper based on disk squeeze mode and experimental

Danxia ZHAO, Changrong LIAO, Qiong LIU, Jing LUO

《机械工程前沿（英文）》 2011年 第6卷 第3期   页码 312-317 doi: 10.1007/s11465-011-0235-x

摘要：

In this paper, a small displacement-type magnetorheological grease (MRG) damper based on disk squeeze mode is proposed. The squeeze flow differential equation is obtained. The Navier slip condition is considered on the surfaces and the boundary compatible condition is established. The radial velocity profiles and the radial pressure distributions are derived respectively, and the mathematical stress expression is calculated. To verify rationality of analytical method, the MRG damper is designed and fabricated according to the technical requirements of an engine vibration isolation system. The experimental damping force from MTS870 Electro-hydraulic Servo with sine wave excitation shows that the proposed analytical method is feasible and provides the reference value for designing MRG damper based on disk squeeze mode.

关键词： magnetorheological grease (MRG)     damper     squeeze model    

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Dynamic characteristics of a magnetorheological pin joint for civil structures

Yancheng LI,Jianchun LI

《机械工程前沿（英文）》 2014年 第9卷 第1期   页码 15-33 doi: 10.1007/s11465-014-0283-0

摘要：

Magnetorheological (MR) pin joint is a novel device in which its joint moment resistance can be controlled in real-time by altering the applied magnetic field. The smart pin joint is intended to be used as a controllable connector between the columns and beams of a civil structure to instantaneously shift the structural natural frequencies in order to avoid resonance and therefore to reduce unwanted vibrations and hence prevent structural damage. As an intrinsically nonlinear device, modelling of this MR fluid based device is a challenging task and makes the design of a suitable control algorithm a cumbersome situation. Aimed at its application in civil structure, the main purpose of this paper is to test and characterise the hysteretic behaviour of MR pin joint. A test scheme is designed to obtain the dynamic performance of MR pin joint in the dominant earthquake frequency range. Some unique phenomena different from those of MR damper are observed through the experimental testing. A computationally-efficient model is proposed by introducing a hyperbolic element to accurately reproduce its dynamic behaviour and to further facilitate the design of a suitable control algorithm. Comprehensive investigations on the model accuracy and dependences of the proposed model on loading condition (frequency and amplitude) and input current level are reported in the last section of this paper.

关键词： Magnetorheological pin joint     hyperbolic hysteresis model experimental testing frequency dependence    

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Experimental and numerical analysis of beam to column joints in steel structures

Gholamreza ABDOLLAHZADEH, Seyed Mostafa SHABANIAN

《结构与土木工程前沿（英文）》 2018年 第12卷 第4期   页码 642-661 doi: 10.1007/s11709-017-0457-z

摘要： The behaviors such as extreme non-elastic response, constant changes in roughness and resistance, as well as formability under extreme loads such as earthquakes are the primary challenges in the modeling of beam-to-column connections. In this research, two modeling methods including mechanical and neural network methods have been presented in order to model the complex hysteresis behavior of beam-to-column connections with flange plate. First, the component-based mechanical model will be introduced in which every source of transformation has been shown only with geometrical and material properties. This is followed by the investigation of a neural network method for direct extraction of information out of experimental data. For the validation of behavioral curves as well as training of the neural network, the experiments were carried out on samples with real dimensions of beam-to-column connections with flange plate in the laboratory. At the end, the combinational modeling framework is presented. The comparisons reveal that the combinational modeling is able to display the complex narrowed hysteresis behavior of the beam-to-column connections with flange plate. This model has also been successfully employed for the prediction of the behavior of a newly designed connection.

关键词： beam to column connections     experiments     component method     neural network model     combinational modeling    

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泰州大桥中塔沉井基础承载力模型试验研究

阮静,胡丰

《中国工程科学》 2012年 第14卷 第5期   页码 57-61

摘要：

泰州大桥中塔位于江中心，基础覆盖层高达200 m。通过多方面比选，基础采用58 m×44 m四角倒圆的矩形沉井，高76 m。为确保泰州大桥中塔沉井基础的安全和稳定，开展了1∶100的模型试验，获取了泰州大桥沉井极限承载力以及沉井埋深、土体含水量、侧壁摩阻力对极限承载力的影响。

关键词： 沉井承载力     泰州大桥     物理模型试验    

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Vibration-based crack prediction on a beam model using hybrid butterfly optimization algorithm with artificial

Abdelwahhab KHATIR; Roberto CAPOZUCCA; Samir KHATIR; Erica MAGAGNINI

《结构与土木工程前沿（英文）》 2022年 第16卷 第8期   页码 976-989 doi: 10.1007/s11709-022-0840-2

摘要： Vibration-based damage detection methods have become widely used because of their advantages over traditional methods. This paper presents a new approach to identify the crack depth in steel beam structures based on vibration analysis using the Finite Element Method (FEM) and Artificial Neural Network (ANN) combined with Butterfly Optimization Algorithm (BOA). ANN is quite successful in such identification issues, but it has some limitations, such as reduction of error after system training is complete, which means the output does not provide optimal results. This paper improves ANN training after introducing BOA as a hybrid model (BOA-ANN). Natural frequencies are used as input parameters and crack depth as output. The data are collected from improved FEM using simulation tools (ABAQUS) based on different crack depths and locations as the first stage. Next, data are collected from experimental analysis of cracked beams based on different crack depths and locations to test the reliability of the presented technique. The proposed approach, compared to other methods, can predict crack depth with improved accuracy.

关键词： damage prediction     ANN     BOA     FEM     experimental modal analysis    

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基于经验学习的创造力支持系统层次结构模型

冯勤超,江孝感,孙锦

《中国工程科学》 2006年 第8卷 第4期   页码 19-23

摘要：

分析了创造力活动过程的特点，讨论了影响人的创造力的认知因素，详细分析了创造力支持系统（CSS）的基本功能，并提出一种基于经验学习的创造力支持系统的层次结构。

关键词： 创造力     认知     创造力支持系统     经验学习    

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Experimental and kinetic study on laminar flame speeds of ammonia/syngas/air at a high temperature and

《能源前沿（英文）》 2022年 第16卷 第2期   页码 263-276 doi: 10.1007/s11708-021-0791-7

摘要： The laminar flame speeds of ammonia mixed with syngas at a high pressure, temperature, and different syngas ratios were measured. The data obtained were fitted at different pressures, temperatures, syngas ratios, and equivalence ratios. Four kinetic models (the Glarborg model, Shrestha model, Mei model, and Han model) were compared and validated with experimental data. Pathway, sensitivity and radical pool analysis are conducted to find out the deep kinetic insight on ammonia oxidation and NO formation. The pathway analysis shows that H abstraction reactions and NHi combination reactions play important roles in ammonia oxidation. NO formation is closely related to H, OH, the O radical produced, and formation reactions. NO is mainly formed from reaction, HNO+ H= NO+ H2. Furthermore, both ammonia oxidation and NO formation are sensitive to small radical reactions and ammonia related reactions.

关键词： ammonia mixed with syngas     laminar flame speed     kinetic model     sensitivity analysis     pathway analysis    

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大比尺高拱坝泄洪振动水弹性模型研究

马斌,练继建,杨敏

《中国工程科学》 2008年 第10卷 第11期   页码 23-29

摘要：

以拉西瓦拱坝为工程背景，采用加重橡胶，建立了大比尺（1∶100）的水弹性模型，全面模拟了“坝体－地基－库水－动荷载”四位一体流固耦联的振动系统。利用该水弹性模型，采用先进的测试手段和数据分析处理软件，对拉西瓦拱坝的模态以及多种泄洪工况下拱坝的振动响应进行全面的测试和分析。采用流激振动反分析方法，求得泄洪振动的等效荷载，得到整个结构的动力响应，最后对泄洪诱发的坝体振动影响作出了评估。

关键词： 拉西瓦拱坝     水弹性模型     流激振动     振动响应     反分析    

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标题 作者 时间 类型 操作

Elevated temperature creep model of parallel wire strands

期刊论文

Hysteretic behavior of cambered surface steel tube damper: Theoretical and experimental research

期刊论文

Geometrical nonlinear deformation model and its experimental study on bimorph giant magnetostrictive

LIU Wei, JIA Zhenyuan, WANG Fuji, ZHANG Yongshun, GUO Dongming

期刊论文

Experimental and computational validation of a scaled train tunnel model using modal analysis

Janice B. D’SOUZA, Sangarapillai KANAPATHIPILLAI

期刊论文

Experimental study on the establishment and maintenance of brain death model with pigs

ZHANG Shuijun, SHI Jihua, ZHAI Wenlong, SONG Yan, CHEN Shi

期刊论文

大跨径钢桥桥道系协同作用试验模型研究

夏国星,钱振东,陈春,刘龑

期刊论文

Numerical and experimental research of the characteristics of concentration solar cells

Zilong WANG, Hua ZHANG, Binlin DOU, Weidong WU, Guanhua ZHANG

期刊论文

Analytical study on damping performances of magnetorheological grease damper based on disk squeeze mode and experimental

Danxia ZHAO, Changrong LIAO, Qiong LIU, Jing LUO

期刊论文

Dynamic characteristics of a magnetorheological pin joint for civil structures

Yancheng LI,Jianchun LI

期刊论文

Experimental and numerical analysis of beam to column joints in steel structures

Gholamreza ABDOLLAHZADEH, Seyed Mostafa SHABANIAN

期刊论文

泰州大桥中塔沉井基础承载力模型试验研究

阮静,胡丰

期刊论文

Vibration-based crack prediction on a beam model using hybrid butterfly optimization algorithm with artificial

Abdelwahhab KHATIR; Roberto CAPOZUCCA; Samir KHATIR; Erica MAGAGNINI

期刊论文

基于经验学习的创造力支持系统层次结构模型

冯勤超,江孝感,孙锦

期刊论文

Experimental and kinetic study on laminar flame speeds of ammonia/syngas/air at a high temperature and

期刊论文

大比尺高拱坝泄洪振动水弹性模型研究

马斌,练继建,杨敏

期刊论文