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Concepts and implementation of strain-based criteria in design codes for steel structures

Reidar BJORHOVDE

《结构与土木工程前沿(英文)》 2012年 第6卷 第3期   页码 210-216 doi: 10.1007/s11709-012-0165-7

摘要: A uniaxial tension test is commonly used to determine the mechanical properties of steel, but it has no meaning for the response of the material in a structure. The test was developed as a consensus solution by producers, fabricators, designers and code writers, to have a standard by which similar materials could be compared to a common base. It does not represent the actual behavior of the steel in a structure, and was never intended to do so. To study the true behavior of the structure and how the material responds it would be better to determine the strains and deformations that will take place during actual service condition. Such characteristics reflect the real behavior, whether in the elastic or inelastic range. If stresses or forces are needed, these are easily determined by the value of the strain and the relevant material modulus, along with the type of cross section, whether elastic or inelastic. The paper addresses the properties of a range of structural steels, how these are incorporated into design standards and how the standards define deformation characteristics and demands for bolted and welded connections.

关键词: steel     stress-strain characteristics     tension test     strain design     actual behavior     improved design codes    

Parametric study on damage control design of SMA dampers in frame-typed steel piers

Xiaoqun LUO, Hanbin GE, Tsutomu USAMI,

《结构与土木工程前沿(英文)》 2009年 第3卷 第4期   页码 384-394 doi: 10.1007/s11709-009-0065-7

摘要: This paper focuses on damage control design of SMA dampers in steel frame piers. A parametric study based on time history analyses is carried out on frame-typed bridge piers with axial-type SMA damping device. The parameters examined are design parameters of strength ratio and stiffness ratio . Seismic performance indexes on displacement and strain are investigated under three JRA recommended Level 2 Ground Type П strong earthquake motions. Design recommendations are suggested following the results of the parametric study.

关键词: damage control design     shape memory alloy     parameter study     displacement-based verification     strain-based verification     time history analysis    

Test-driven verification/validation of model transformations

László LENGYEL,Hassan CHARAF

《信息与电子工程前沿(英文)》 2015年 第16卷 第2期   页码 85-97 doi: 10.1631/FITEE.1400111

摘要: Why is it important to verify/validate model transformations? The motivation is to improve the quality of the transformations, and therefore the quality of the generated software artifacts. Verified/validated model transformations make it possible to ensure certain properties of the generated software artifacts. In this way, verification/validation methods can guarantee different requirements stated by the actual domain against the generated/modified/optimized software products. For example, a verified/validated model transformation can ensure the preservation of certain properties during the model-to-model transformation. This paper emphasizes the necessity of methods that make model transformation verified/validated, discusses the different scenarios of model transformation verification and validation, and introduces the principles of a novel test-driven method for verifying/validating model transformations. We provide a solution that makes it possible to automatically generate test input models for model transformations. Furthermore, we collect and discuss the actual open issues in the field of verification/validation of model transformations.

关键词: Graph rewriting based model transformations     Verification/validation     Test-driven verification    

高钢级钢管和高压输送:我国油气输送管道的重大技术进步

李鹤林,吉玲康,田伟

《中国工程科学》 2010年 第12卷 第5期   页码 84-90

摘要:

近年来,我国管道企业和相关科研院所联合攻关,取得了一批关键技术成果,这些成果包括:研制了X70,X80钢级高性能管线钢及焊管、管件;突破国际上螺旋缝埋弧焊管的使用禁区,确立了具有中国特色的“大口径高压输送主干线螺旋埋弧焊管与直缝埋弧焊管联合使用”的技术路线;在国内首次研究了高压输气管道动态断裂与止裂问题,采用Battelle双曲线模型预测了西气东输和西气东输二线等管道延性断裂的止裂韧性;在国内首次研究了油气管道基于应变的设计方法,解决了该设计方法及抗大变形管线钢管在强震区和活动断层管段应用的技术难题;解决了高强度焊管的腐蚀控制和应变时效控制等技术。

关键词: 油气管道     管线钢     螺旋缝埋弧焊管     止裂韧性     基于应变的设计    

FEM-based strain analysis study for multilayer sheet forming process

Rongjing ZHANG,Lihui LANG,Rizwan ZAFAR

《机械工程前沿(英文)》 2015年 第10卷 第4期   页码 373-379 doi: 10.1007/s11465-015-0371-9

摘要:

Fiber metal laminates have many advantages over traditional laminates (e.g., any type of fiber and resin material can be placed anywhere between the metallic layers without risk of failure of the composite fabric sheets). Furthermore, the process requirements to strictly control the temperature and punch force in fiber metal laminates are also less stringent than those in traditional laminates. To further explore the novel method, this study conducts a finite element method-based (FEM-based) strain analysis on multilayer blanks by using the 3A method. Different forming modes such as wrinkling and fracture are discussed by using experimental and numerical studies. Hydroforming is used for multilayer forming. The Barlat 2000 yield criteria and DYNAFORM/LS-DYNA are used for the simulations. Optimal process parameters are determined on the basis of fixed die-binder gap and variable cavity pressure. The results of this study will enhance the knowledge on the mechanics of multilayer structures formed by using the 3A method and expand its commercial applications.

关键词: finite element method (FEM)     strain analysis     multilayer sheet forming    

Multiple damage detection in complex bridges based on strain energy extracted from single point measurement

Alireza ARABHA NAJAFABADI, Farhad DANESHJOO, Hamid Reza AHMADI

《结构与土木工程前沿(英文)》 2020年 第14卷 第3期   页码 722-730 doi: 10.1007/s11709-020-0624-5

摘要: Strain Energy of the structure can be changed with the damage at the damage location. The accurate detection of the damage location using this index in a force system is dependent on the degree of accuracy in determining the structure deformation function before and after damage. The use of modal-based methods to identify damage in complex bridges is always associated with problems due to the need to consider the effects of higher modes and the adverse effect of operational conditions on the extraction of structural modal parameters. In this paper, the deformation of the structure was determined by the concept of influence line using the Betti-Maxwell theory. Then two damage detection indicators were developed based on strain energy variations. These indices were presented separately for bending and torsion changes. Finite element analysis of a five-span concrete curved bridge was done to validate the stated methods. Damage was simulated by decreasing stiffness at different sections of the deck. The response regarding displacement of a point on the deck was measured along each span by passing a moving load on the bridge at very low speeds. Indicators of the strain energy extracted from displacement influence line and the strain energy extracted from the rotational displacement influence line (SERIL) were calculated for the studied bridge. The results show that the proposed methods have well identified the location of the damage by significantly reducing the number of sensors required to record the response. Also, the location of symmetric damages is detected with high resolution using SERIL.

关键词: damage detection     strain energy     influence line     complex bridges     rotation displacement    

Expert networks as science-policy interlocutors in the implementation of a monitoring reporting and verification

Remi CHANDRAN, Tsuyoshi FUJITA, Minoru FUJII, Shuichi ASHINA, Kei GOMI, Rizaldi BOER, Muhammad ARDIANSYAH, Seiya MAKI

《能源前沿(英文)》 2018年 第12卷 第3期   页码 376-388 doi: 10.1007/s11708-018-0559-x

摘要:

The Paris Agreement, which entered into effect in 2016, emphasizes a definite timeline for communicating and maintaining successive nationally determined contributions (NDCs) that it plans to achieve in addressing climate change. This calls for the development of a measurement, reporting and verification (MRV) system and a Capacity-building Initiative for Transparency (CBIT). Though such actions are universally accepted by the Parties to the Paris Agreement, earlier studies have shown that there remain technological, social, political and financial constrains which will affect the development and deployment of such a system. In this paper, using a case study on MRV implementation in Bogor City in Indonesia, how the above-mentioned challenges can be overcome is outlined through a technological and policy innovation process where scientists and technologists (collectively referred as expert networks) can join hands with local governments and national policy makers in designing, development and implementation of an MRV system that meets the local, national and global requirements. Through the case study it is further observed that expert networks can act as interactive knowledge generators and policy interlocutors in bridging technology with policy. To be specific, first, a brief history of the international context of MRV and CBIT is outlined. Next, the theoretical underpinning of the study is contextualized within the existing theories related to public policy and international relations. Finally, the case study is outlined and investigated where the engagement of an expert-network and policy makers in the design, development and implementation of an MRV tool is showcased.

关键词: MRV     CBIT     UNFCCC     Indonesia     Japan     ICT based monitoring     climate policy    

基于随机森林模型的滑动轨迹人机识别 Research Articles

Zhen-yi XU, Yu KANG, Yang CAO, Yu-xiao YANG

《信息与电子工程前沿(英文)》 2019年 第20卷 第7期   页码 925-929 doi: 10.1631/FITEE.1700442

摘要: 识别码在维护网络安全的人机身份验证中得到广泛应用。人机身份验证面临的挑战包括对人与机器滑动轨迹的正确检测。提出一种基于滑动轨迹数据集的人机识别随机森林模型。通过多维性能评价指标,包括识别准确率、识别召回率、识别误报率、识别漏报率、F值和加权准确率,验证该随机森林模型以及基准模型(逻辑回归模型和支持向量机)。随机森林模型多维性能评价指标优于基准模型。

关键词: 人机识别;随机森林;支持向量机;逻辑回归;多维性能评价指标    

一种基于描述逻辑的体系质量需求建模与验证方法 Article

Qing-long WANG,Zhi-xue WANG,Ting-ting ZHANG,Wei-xing ZHU

《信息与电子工程前沿(英文)》 2017年 第18卷 第3期   页码 346-361 doi: 10.1631/FITEE.1500309

摘要: 在体系顶层设计问题中,体系质量需求分析的关键是体系需求的建模以及自动验证,需要合适的建模方法来描述体系质量需求以及验证质量需求是否满足体系的能力需求。针对体系质量需求建模和验证问题,本文提出一种基于描述逻辑的体系质量需求建模与验证方法。首先,为解决体系功能和非功能需求的描述问题,通过添加模糊构造子扩展统一建模语言(Unified Modeling Language, UML)中的类和关系并定义了基于元模型的领域特定建模语言以实现体系质量需求中模糊和不确定概念的建模。随后提出了基于云模型的体系质量需求评估方法实现了对体系质量需求的评估。然后,提出了模型转换算法将模糊UML构建的体系需求模型转换为描述逻辑本体模型,并通过使用描述逻辑本体推理工具实现需求模型的自动化验证。最后,通过一个案例验证和演示了本文方法的正确性和可行性。

关键词: 体系;云模型;描述逻辑;需求验证    

Adaptive selective ES-FEM limit analysis of cracked plane-strain structures

H. NGUYEN-XUAN,T. RABCZUK

《结构与土木工程前沿(英文)》 2015年 第9卷 第4期   页码 478-490 doi: 10.1007/s11709-015-0317-7

摘要: This paper presents a simple and efficient approach for predicting the plastic limit loads in cracked plane-strain structures. We use two levels of mesh repartitioning for the finite element limit analysis. The master level handles an adaptive primal-mesh process through a dissipation-based indicator. The slave level performs the subdivision of each triangle into three sub-triangles and constitutes a dual mesh from a pair of two adjacent sub-triangles shared by common edges of the primal mesh. Applying a strain smoothing projection to the strain rates on the dual mesh, the incompressibility constraint and the flow rule constraint are imposed over the edge-based smoothing domains and everywhere in the problem domain. The limit analysis problem is recast into the compact form of a second-order cone programming (SOCP) for the purpose of exploiting interior-point solvers. The present method retains a low number of optimization variables. It offers a convenient way for designing and solving the large-scale optimization problems effectively. Several benchmark examples are given to show the simplicity and effectiveness of the present method.

关键词: cracked structure     limit analysis     von Mises criterion     edge-based strain smoothing     second-order cone programming     adaptive    

EMD-Tnorm得分规整策略在说话人确认中的应用

李燕萍,丁辉,唐振民

《中国工程科学》 2010年 第12卷 第2期   页码 95-100

摘要:

从两个方面对确认系统进行了改进,在模型方面,扩展了MixMax模型,对复杂的背景噪声等干扰因素在训练说话人模型的同时也进行了建模,最大程度上消除噪声的影响,对说话人的特征分布进行了更真实的表征;在得分方面,提出了一种改进的得分规整策略,基于EMD距离从所有背景说话人集合中自适应选择最接近的一定数量的模型构成说话人特定的背景集合,从而进行得分归一化。实验结果表明,该方法能够同时针对说话人和测试环境的不同进行补偿,进一步降低了误识率和漏警率,获得了很好的确认性能。

关键词: 说话人确认     鲁棒性     EMD距离     MixMax模型    

Semantic Consistency and Correctness Verification of Digital Traffic Rules

Lei Wan,Changjun Wang,Daxin Luo,Hang Liu,Sha Ma,Weichao Hu,

《工程(英文)》 doi: 10.1016/j.eng.2023.04.016

摘要: The consensus of the automotive industry and traffic management authorities is that autonomous vehicles must follow the same traffic laws as human drivers. Using formal or digital methods, natural language traffic rules can be translated into machine language and used by autonomous vehicles. In this paper, a translation flow is designed. Beyond the translation, a deeper examination is required, because the semantics of natural languages are rich and complex, and frequently contain hidden assumptions. The issue of how to ensure that digital rules are accurate and consistent with the original intent of the traffic rules they represent is both significant and unresolved. In response, we propose a method of formal verification that combines equivalence verification with model checking. Reasonable and reassuring digital traffic rules can be obtained by utilizing the proposed traffic rule digitization flow and verification method. In addition, we offer a number of simulation applications that employ digital traffic rules to assess vehicle violations. The experimental findings indicate that our digital rules utilizing metric temporal logic (MTL) can be easily incorporated into simulation platforms and autonomous driving systems (ADS).

关键词: Autonomous driving     Traffic rules     Digitization     Formalization     Verification    

Availability growth models and verification of power equipment

Jinyuan SHI, Jiamin XU

《能源前沿(英文)》 2021年 第15卷 第2期   页码 529-538 doi: 10.1007/s11708-019-0624-0

摘要: The general availability growth models for large scale complicated repairable system such as electric generating units, power station auxiliaries, and transmission and distribution installations are presented. The calculation formulas for the maintenance coefficient, mathematical expressions for general availability growth models, ways for estimating, and fitting on checking the parameters of the model are introduced. Availability growth models for electric generating units, power station auxiliaries, and transmission and distribution installations are given together with verification examples for availability growth models of 320–1000 MW nuclear power units and 1000 MW thermal power units, 200–1000 MW power station auxiliaries, and 220–500 kV transmission and distribution installations. The verification results for operation availability data show that the maintenance coefficients for electric generating units, power station auxiliaries, transmission and distribution installations conform to the power function, and general availability growth models conform to rules of availability growth tendency of power equipment.

关键词: repairable system     power equipment     electric generating unit     power station auxiliary     transmission and distribution installation     reliability     availability     availability growth model    

Modelling and experimental verification on concrete-filled steel tubular columns with L or T section

LU Xilin, LI Xueping, WANG Dan

《结构与土木工程前沿(英文)》 2007年 第1卷 第2期   页码 163-169 doi: 10.1007/s11709-007-0017-z

摘要: Concrete-filled steel tubular columns with L or T sections were analyzed in this paper. According to the confining mechanism, the stress-strain constitutive model was put forward, and calculated results were compared with experimental records. After that, the hysteretic rules for the in-filled concrete were constructed, aiming at the analysis on the seismic behavior of composite members. The simulation analysis was performed by programming it in Fortran. The models in this paper can be applied in the program of time history analysis on tall buildings with concrete-filled steel tubular columns with L or T sections.

关键词: hysteretic     confining mechanism     Concrete-filled     in-filled     composite    

Establishment and verification of a shrinking core model for dilute acid hydrolysis of lignocellulose

Cunwen WANG, Xiaoling DUAN, Weiguo WANG, Zihao LI, Yuanhang QIN

《能源前沿(英文)》 2012年 第6卷 第4期   页码 413-419 doi: 10.1007/s11708-012-0212-z

摘要: The kinetics of lignocellulose hydrolysis under the conditions of high temperature and dilute acid (mass fraction 0.05%) was investigated in this paper. By studying the reducing sugar concentration versus reaction temperature (170°C–220°C) and reaction time (150–1800 s) during the hydrolysis process of five kinds of crop straw (rice, wheat, cotton, rape and corn), the shrinking core model was established, and the differential equation of the model and its analytical solution were obtained. With a numerical calculation method, the kinetic equation was estimated, and the degradation of reducing sugar obeyed first-order kinetics was obtained. The calculated results from the equations agreed well with the original experimental data. The calculation by the model showed that the reducing sugar concentration increases as the size of the particles decrease, and the uniform particles increase.

关键词: lignocellulose     dilute acid hydrolysis     shrinking core model    

标题 作者 时间 类型 操作

Concepts and implementation of strain-based criteria in design codes for steel structures

Reidar BJORHOVDE

期刊论文

Parametric study on damage control design of SMA dampers in frame-typed steel piers

Xiaoqun LUO, Hanbin GE, Tsutomu USAMI,

期刊论文

Test-driven verification/validation of model transformations

László LENGYEL,Hassan CHARAF

期刊论文

高钢级钢管和高压输送:我国油气输送管道的重大技术进步

李鹤林,吉玲康,田伟

期刊论文

FEM-based strain analysis study for multilayer sheet forming process

Rongjing ZHANG,Lihui LANG,Rizwan ZAFAR

期刊论文

Multiple damage detection in complex bridges based on strain energy extracted from single point measurement

Alireza ARABHA NAJAFABADI, Farhad DANESHJOO, Hamid Reza AHMADI

期刊论文

Expert networks as science-policy interlocutors in the implementation of a monitoring reporting and verification

Remi CHANDRAN, Tsuyoshi FUJITA, Minoru FUJII, Shuichi ASHINA, Kei GOMI, Rizaldi BOER, Muhammad ARDIANSYAH, Seiya MAKI

期刊论文

基于随机森林模型的滑动轨迹人机识别

Zhen-yi XU, Yu KANG, Yang CAO, Yu-xiao YANG

期刊论文

一种基于描述逻辑的体系质量需求建模与验证方法

Qing-long WANG,Zhi-xue WANG,Ting-ting ZHANG,Wei-xing ZHU

期刊论文

Adaptive selective ES-FEM limit analysis of cracked plane-strain structures

H. NGUYEN-XUAN,T. RABCZUK

期刊论文

EMD-Tnorm得分规整策略在说话人确认中的应用

李燕萍,丁辉,唐振民

期刊论文

Semantic Consistency and Correctness Verification of Digital Traffic Rules

Lei Wan,Changjun Wang,Daxin Luo,Hang Liu,Sha Ma,Weichao Hu,

期刊论文

Availability growth models and verification of power equipment

Jinyuan SHI, Jiamin XU

期刊论文

Modelling and experimental verification on concrete-filled steel tubular columns with L or T section

LU Xilin, LI Xueping, WANG Dan

期刊论文

Establishment and verification of a shrinking core model for dilute acid hydrolysis of lignocellulose

Cunwen WANG, Xiaoling DUAN, Weiguo WANG, Zihao LI, Yuanhang QIN

期刊论文