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Lamb wave propagation modeling for structure health monitoring

Xiaoyue ZHANG, Shenfang YUAN, Tong HAO

《机械工程前沿(英文)》 2009年 第4卷 第3期   页码 326-331 doi: 10.1007/s11465-009-0045-6

摘要: This study aims to model the propagation of Lamb waves used in structure health monitoring. A number of different numerical computational techniques have been developed for wave propagation studies. The local interaction simulation approach, used for modeling sharp interfaces and discontinuities in complex media (LISA/SIM theory), has been effectively applied to numerical simulations of elastic wave interaction. This modeling is based on the local interaction simulation approach theory and is finally accomplished through the finite elements software Ansys11. In this paper, the Lamb waves propagating characteristics and the LISA/SIM theory are introduced. The finite difference equations describing wave propagation used in the LISA/SIM theory are obtained. Then, an anisotropic metallic plate model is modeled and a simulating Lamb waves signal is loaded on. Finally, the Lamb waves propagation modeling is implemented.

关键词: Lamb wave     modeling     LISA/SIM theory     finite difference equation     finite element    

Three-dimensional finite difference analysis of shallow sprayed concrete tunnels crossing a reverse fault

Masoud RANJBARNIA, Milad ZAHERI, Daniel DIAS

《结构与土木工程前沿(英文)》 2020年 第14卷 第4期   页码 998-1011 doi: 10.1007/s11709-020-0621-8

摘要: Urban tunnels crossing faults are always at the risk of severe damages. In this paper, the effects of a reverse and a normal fault movement on a transversely crossing shallow shotcreted tunnel are investigated by 3D finite difference analysis. After verifying the accuracy of the numerical simulation predictions with the centrifuge physical model results, a parametric study is then conducted. That is, the effects of various parameters such as the sprayed concrete thickness, the geo-mechanical properties of soil, the tunnel depth, and the fault plane dip angle are studied on the displacements of the ground surface and the tunnel structure, and on the plastic strains of the soil mass around tunnel. The results of each case of reverse and normal faulting are independently discussed and then compared with each other. It is obtained that deeper tunnels show greater displacements for both types of faulting.

关键词: urban tunnel     sprayed concrete     reverse fault     normal fault     finite difference analysis    

浅水波方程的二维数值模拟

向波,米晓,纪昌明,罗庆松

《中国工程科学》 2008年 第10卷 第7期   页码 118-124

摘要:

非结构的三角形网格适应于复杂不规则的边界,在此基础上采用有限体积法离散浅水波方程,并结 合有限差分法建立了一种新的离散格式,使得界面通量计算达到二阶精度。为了验证所建立的模型,分别对 二维弯道和二维部分溃坝流动进行了模拟计算,比较了一阶精度和二阶精度的结果,并与其他的方法进行了 比较,得到了较好的结果。

关键词: 圆锥滚子轴承     振动     灰色模糊聚类分析    

用二极管统一构建两个n阶电路网络 Research Article

林小燕,谭志中

《信息与电子工程前沿(英文)》 2023年 第24卷 第2期   页码 289-298 doi: 10.1631/FITEE.2200360

摘要: 本文通过二极管将两个不同的n阶拓扑电路网络连接起来,建立起一个统一的网络模型,这是一个以前没有研究解决的新问题。该网络模型不仅包含五个电阻元件,还包含二极管器件,因此该网络包含多种不同的网络类型。该问题可以通过三个主要步骤来解决:首先,将网络简化为两个不同的等效电路模型;其次,应用基尔霍夫定律建立非线性差分方程模型;最后,对结构相似的两个方程进行统一处理,并利用等效变换技术得到非线性差分方程的通解。作为应用,文章推导出几个有趣的特殊结果。网络模型的研究非常重要,可以应用于跨学科研究。

关键词: 复杂网络;等效变换;非线性差分方程;等效电阻    

锯材高频-对流联合加热干燥传热传质数学模型

贾潇然,赵景尧,蔡英春

《中国工程科学》 2014年 第16卷 第4期   页码 106-112

摘要:

本文以多孔介质传热传质理论为基础,结合高频-对流联合加热干燥过程中热质传递的机理及特 性,通过质量、动量、能量守恒方程等建立了高频-对流联合加热干燥过程中锯材热质传递数学模型并给出相应定解条件。模型中每个自变量及因变量都有独立的控制方程,利用控制容积法建立相应控制方程的差分格式,将耦合偏微分方程按步骤解耦,以便于利用Matlab 或FORTRAN等编程求解时,达到每个自变量均可以独立求解的目的。

关键词: 锯材     高频-对流干燥     数学模型     差分方程    

Application of random set method in a deep excavation: based on a case study in Tehran cemented alluvium

Arash SEKHAVATIAN, Asskar Janalizadeh CHOOBBASTI

《结构与土木工程前沿(英文)》 2019年 第13卷 第1期   页码 66-80 doi: 10.1007/s11709-018-0461-y

摘要: The design of high-rise buildings often necessitates ground excavation, where buildings are in close proximity to the construction, thus there is a potential for damage to these structures. This paper studies an efficient user-friendly framework for dealing with uncertainties in a deep excavation in layers of cemented coarse grained soil located in Tehran, Iran by non-deterministic Random Set (RS) method. In order to enhance the acceptability of the method among engineers, a pertinent code was written in FISH language of FLAC2D software which enables the designers to run all simulations simultaneously, without cumbersome procedure of changing input variables in every individual analysis. This could drastically decrease the computational effort and cost imposed to the project, which is of great importance especially to the owners. The results are presented in terms of probability of occurrence and most likely values of the horizontal displacement at top of the wall at every stage of construction. Moreover, a methodology for assessing the credibility of the uncertainty model is presented using a quality indicator. It was concluded that performing RS analysis before the beginning of every stage could cause great economical savings, while improving the safety of the project.

关键词: uncertainty     reliability analysis     deep excavations     random set method     finite difference method    

Temperature difference-powered carbon nanotube bearings

Quanwen HOU, Bingyang CAO, Zengyuan GUO

《能源前沿(英文)》 2011年 第5卷 第1期   页码 49-52 doi: 10.1007/s11708-010-0111-0

摘要: Molecular dynamics simulations are conducted to study the motion of carbon nanotube-based nanobearings powered by temperature difference. When a temperature difference exists between stator nanotubes, the rotor nanotubes acquire a higher temperature, which arises from the interaction between phonon currents and nanotubes. The thermal driving force increases with the increase in temperature difference between the stators, an increase that is nearly proportional to the temperature difference. Confined by the minimum energy track, the (5, 5)@(10, 10) nanotube bearings only translate along the axis direction but without successive rotation.

关键词: temperature difference-induced motion     carbon nanotubes     nanobearing     molecular dynamics simulation    

Cyclic stress-strain behavior of structural steel with yield-strength up to 460 N/mm

Yiyi CHEN,Wei SUN,Tak-Ming CHAN

《结构与土木工程前沿(英文)》 2014年 第8卷 第2期   页码 178-186 doi: 10.1007/s11709-014-0245-y

摘要: This paper presents a constitutive model based on Ramberg-Osgood equation to describe the hysteresis material behavior of structural carbon steel with nominal yield strength between 235 to 420 N/mm . The proposed model was calibrated against a series of cyclic material tests with strain amplitude varying from 0.5% to 2.0%. A simple relationship between the modular parameter and the yield strength was proposed. The calibrated Ramberg-Osgood model revealed excellent agreement with the experimental results and captured further the experimental behavior of test specimens with nominal yield strength of 460 N/mm . The proposed constitutive model was also adopted in conjunction with the combined kinematic/isotropic materials description in ABAQUS to mimic a full scale experimental test under cyclic loading. The numerical results revealed close agreement with the experimental observations.

关键词: constitutive model     finite element analysis     hysteresis curve     Ramberg-Osgood equation    

类差分平衡函数的性质及其应用

张文英,李世取

《中国工程科学》 2004年 第6卷 第3期   页码 45-52

摘要:

定义了布尔函数的类差分和类差分平衡函数,研究了类差分平衡函数的密码学性质以及构造方法。作为类差分平衡函数的应用,给出了〓上逻辑函数是完全非线性函数的充要条件,并在首先分析得到所有四元类差分平衡函数的基础上,编程搜索出〓上所有的完全非线性函数。

关键词: Bent函数     完全非线性函数     2-基展开     类差分     类自相关函数     类差分平衡函数    

Synthesis of Intermittent-Motion Linkages with Slight Difference in Length Between Links

CHEN Xin-bo, YU Zhen

《机械工程前沿(英文)》 2006年 第1卷 第1期   页码 76-79 doi: 10.1007/s11465-005-0007-6

摘要:

The design of intermittent-motion linkages using traditional methods is usually complicated. In this paper, (1) a new method for realizing intermittent motion, using linkages with a slight difference in length between links, is studied; (2) some new types of intermittent-motion linkages and their software for visual analysis and design are developed; and (3) influences of some design parameters on intermittent-motion characteristics are clarified. Results confirmed that the theory and the software are useful, making the synthesis of intermittent-motion linkages clear and easy.

关键词: synthesis     useful     intermittent     intermittent-motion     traditional    

温差能与低温海水资源综合利用研究

付强,王国荣,周守为,钟林,张理,余兴勇,杨浦

《中国工程科学》 2021年 第23卷 第6期   页码 52-60 doi: 10.15302/J-SSCAE-2021.06.007

摘要:

我国海洋温差能资源量巨大,主要分布在广东省和南海海域,是区域能源结构优化以实现碳达峰、碳中和的有效支撑,也是未来我国南海、 21 世纪海上丝绸之路沿线诸多岛屿能源补给保障的重要途径;目前海洋温差能发电( OTEC)技术和装备尚处于实验阶段,兆瓦级试验电站建设成本巨大,整体技术成熟度不及商业级利用规模,亟待发展突破。本文总结了国内外 OTEC 及综合利用的发展模式、技术装备所面临的挑战,针对南海温差能资源开发困境、广东省液化天然气( LNG)冷能资源浪费等情况,提出了以 LNG 气化的低温海水替代深层海水进行温差能发电的新途径。建议以珠海 LNG 气化站为例,探索 LNG 冷能回收 – 温差能发电、低温冷海水综合利用示范基地的发展模式;通过初步概算示范基地的投资与收益,完成了相应模式的经济与技术可行性论证。相关发展模式建议、应用案例论证过程,可为我国温差能与低温海水资源综合利用提供技术借鉴和应用参考。

关键词: 海洋温差能     低温海水资源     LNG冷能     综合利用     温差能发电    

The Difference Effect of Environmental Regulation on Two Stages of Technology Innovation in China’s Manufacturing

Bao-long Yuan,Sheng-gang Ren,Xing Hu,Xuan-yu Yang

《工程管理前沿(英文)》 2016年 第3卷 第1期   页码 24-29 doi: 10.15302/J-FEM-2016007

摘要: This paper divides technological innovation into two stages: technology development and technology transfer. Then the authors use the panel data of 28 manufacturing industries during 2003–2012 to test the econometric regression model for the industry of the sub stages, which is a regulation on technological innovation in the environment. The results show that: (1) environmental regulation has a significant role in promoting China’s manufacturing technology research patent achievements, and technology into new products, and this indicated that “Porter hypothesis” in the manufacturing sector has been verified; (2) R&D and transfer expenditure have a positive impact on technological innovation. Finally, the authors put forward the corresponding policy recommendations for industry of the environmental regulation on the impact of technological innovation in phases.

关键词: environmental regulation     technology innovation     stage difference     manufacturing    

Comparison of the performance of traditional advection-dispersion equation and mobile-immobile model

Haizhu HU,Xiaomin MAO

《农业科学与工程前沿(英文)》 2016年 第3卷 第3期   页码 241-248 doi: 10.15302/J-FASE-2016108

摘要: The traditional advection-dispersion equation (ADE) and the mobile-immobile model (MIM) are widely used to describe solute transport in heterogeneous porous media. However, the fitness of the two models is case-dependent. In this paper, the transport of conservative, adsorbing and degradable solutes through a 1 m heterogeneous soil column under steady flow condition was simulated by ADE and MIM, and sensitivity analysis was conducted. Results show that MIM tends to prolong the breakthrough process and decrease peak concentration for all three solutes, and tailing and skewness are more pronounced with increasing dispersivity. Breakthrough curves of the adsorbing solute simulated by MIM are less sensitive to the retardation factor compared with the results simulated by ADE. The breakthrough curves of degradable solute obtained by MIM and ADE nearly overlap with a high degradation rate coefficient, indicating that MIM and ADE perform similarly for simulating degradable solute transport when biochemical degradation prevails over the mass exchange between mobile and immobile zones. The results suggest that the physical significance of dispersivity should be carefully considered when MIM is applied to simulate the degradable solute transport and/or ADE is applied to simulate the adsorbing solute transport in highly dispersive soils.

关键词: solute transport     advection dispersion equation (ADE)     mobile-immobile model (MIM)     conservative solute     adsorbing solute     degradable solute     PHREEQC-2    

Optimal design of extractive dividing-wall column using an efficient equation-oriented approach

Yingjie Ma, Nan Zhang, Jie Li, Cuiwen Cao

《化学科学与工程前沿(英文)》 2021年 第15卷 第1期   页码 72-89 doi: 10.1007/s11705-020-1977-y

摘要: The extractive dividing-wall column (EDWC) is one of the most efficient technologies for separation of azeotropic or close boiling-point mixtures, but its design is fairly challenging. In this paper we extend the hybrid feasible path optimisation algorithm (Ma Y, McLaughlan M, Zhang N, Li J. Computers & Chemical Engineering, 2020, 143: 107058) for such optimal design. The tolerances-relaxation integration method is refined to allow for long enough integration time that can ensure the solution of the pseudo-transient continuation simulation close to the steady state before the required tolerance is used. To ensure the gradient and Jacobian information available for optimisation, we allow a relaxed tolerance for the simulation in the sensitivity analysis mode when the simulation diverges under small tolerance. In addition, valid lower bounds on purity of the recycled entrainer and the vapour flow rate in column sections are imposed to improve computational efficiency. The computational results demonstrate that the extended hybrid algorithm can achieve better design of the EDWC compared to those in literature. The energy consumption can be reduced by more than 20% compared with existing literature report. In addition, the optimal design of the heat pump assisted EDWC is achieved using the improved hybrid algorithm for the first time.

关键词: design     extractive dividing-wall column     equation-oriented optimisation     pseudo-transient continuation model     hybrid algorithm    

深水钻井隔水导管挠曲方程和固有频率的计算及其研究

姜伟

《中国工程科学》 2011年 第13卷 第5期   页码 66-73

摘要:

从深水钻井应用的隔水导管的使用实际情况出发,应用弹塑性力学中的位移复分原理的Ritz法,考虑了隔水导管所受到的轴向张力T和隔水导管受力产生的倾角α以及由于自重q所产生的自重横向分力qsin α和轴向分力qcos α,建立了较为合理的挠曲方程,并且由此得到隔水导管的固有振动频率的简易计算求解方法。由于该挠曲方程结合了钻具的实际情况,其挠曲方程的约束条件采用的是一端铰支、一端自由的形式,因此其研究更接近实际情况,研究旨在为深水钻井隔水导管的合理使用设计和选择,提供一种更快捷实用的方法,对深水钻井作业有一定的指导意义。

关键词: 深水钻井     隔水导管     挠曲方程     固有频率     形状函数    

标题 作者 时间 类型 操作

Lamb wave propagation modeling for structure health monitoring

Xiaoyue ZHANG, Shenfang YUAN, Tong HAO

期刊论文

Three-dimensional finite difference analysis of shallow sprayed concrete tunnels crossing a reverse fault

Masoud RANJBARNIA, Milad ZAHERI, Daniel DIAS

期刊论文

浅水波方程的二维数值模拟

向波,米晓,纪昌明,罗庆松

期刊论文

用二极管统一构建两个n阶电路网络

林小燕,谭志中

期刊论文

锯材高频-对流联合加热干燥传热传质数学模型

贾潇然,赵景尧,蔡英春

期刊论文

Application of random set method in a deep excavation: based on a case study in Tehran cemented alluvium

Arash SEKHAVATIAN, Asskar Janalizadeh CHOOBBASTI

期刊论文

Temperature difference-powered carbon nanotube bearings

Quanwen HOU, Bingyang CAO, Zengyuan GUO

期刊论文

Cyclic stress-strain behavior of structural steel with yield-strength up to 460 N/mm

Yiyi CHEN,Wei SUN,Tak-Ming CHAN

期刊论文

类差分平衡函数的性质及其应用

张文英,李世取

期刊论文

Synthesis of Intermittent-Motion Linkages with Slight Difference in Length Between Links

CHEN Xin-bo, YU Zhen

期刊论文

温差能与低温海水资源综合利用研究

付强,王国荣,周守为,钟林,张理,余兴勇,杨浦

期刊论文

The Difference Effect of Environmental Regulation on Two Stages of Technology Innovation in China’s Manufacturing

Bao-long Yuan,Sheng-gang Ren,Xing Hu,Xuan-yu Yang

期刊论文

Comparison of the performance of traditional advection-dispersion equation and mobile-immobile model

Haizhu HU,Xiaomin MAO

期刊论文

Optimal design of extractive dividing-wall column using an efficient equation-oriented approach

Yingjie Ma, Nan Zhang, Jie Li, Cuiwen Cao

期刊论文

深水钻井隔水导管挠曲方程和固有频率的计算及其研究

姜伟

期刊论文