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利用承受时间方法评估钢框架的结构损伤

钢结构 2008年第8期23卷 83-83页

作者： h.e. estekanchi K. Arjomandi A. Vafai

在持续时间方法中,结构受到逐渐加强的地面加速度影响,并根据其在预定耐力标准中所能承受的最长时间判断其抗震性能。承受时间方法是将损伤指数作为耐力准则。将钢框架非线性时程分析中得到的各种损伤指数的数值,与同样加速度水平下持... 详细信息

在持续时间方法中,结构受到逐渐加强的地面加速度影响,并根据其在预定耐力标准中所能承受的最长时间判断其抗震性能。承受时间方法是将损伤指数作为耐力准则。将钢框架非线性时程分析中得到的各种损伤指数的数值,与同样加速度水平下持续时间方法中得到结果相对比。结果显示,可以使用承受时间分析来估计各种损伤指标。同时讨论了这种方法的优势、准确性和局限性。

关键词：承受时间方法损伤指数钢框架动态弹塑性分析抗震设计

Collapse assessment of steel moment frames using endurance time method

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earthquake engineering and engineering Vibration 2015年第2期14卷 347-360页

作者： e.Rahimi h.e.estekanchi Department of Civil engineering Sharif University of Technology (SUT)

In endurance time(eT) method structures are subjected to a set of predesigned intensifying excitations. These excitations are produced in a way that their response spectrum, while complying with a specifi ed spectrum, intensifi es with time so they can be used approximately to simulate the average effects of several ground motions scaled to different intensities. In this paper applicability of the eT method for evaluating collapse potential of buildings is investigated. A set of four steel moment frames is used for collapse assessment. The process of using eT method in collapse evaluation is explained and the results are compared with incremental dynamic analysis(IDA) results. It is shown that although the computational effort using the eT method is much less than the IDA analysis, the results of both methods are consistent. Finally collapse fragility curves using eT and IDA methods are produced and it is shown that the probabilities of collapse in different hazard levels are also consistent.

关键词： endurance time method collapse analysis incrementa

Probabilistic seismic loss estimation via endurance time method

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earthquake engineering and engineering Vibration 2017年第1期16卷 233-245页

作者： ehsan Tafakori Saeid Pourzeynali homayoon e. estekanchi Department of Civil engineering Faculty of EngineeringUniversity of GuilanP.O.Box 41635-3756RashtIran Department of Civil engineering Sharif University of TechnologyP.O.Box 11155-9313TehranIran

Probabilistic Seismic Loss estimation is a methodology used as a quantitative and explicit expression of the performance of buildings using terms that address the interests of both owners and insurance companies. Applying the ATC 58 approach for seismic loss assessment of buildings requires using Incremental Dynamic Analysis （IDA）, which needs hundreds of time-consuming analyses, which in turn hinders its wide application. The endurance Time Method （eTM） is proposed herein as part of a demand propagation prediction procedure and is shown to be an economical alternative to IDA. Various scenarios were considered to ach.e.e this purpose and their appropriateness has been evaluated using statistical methods. The most precise and efficient scenario was validated through comparison against IDA driven response predictions of 34 code conforming benchmark structures and was proven to be sufficiently precise while offering a great deal of efficiency. The loss values were estimated by replacing IDA with the proposed eTM-based procedure in the ATC 58 procedure and it was fotmd that these values suffer from varying inaccuracies, which were attributed to the discretized nature of damage and loss prediction functions provided by ATC 58.

关键词： performance-based earthquake engineering probabilistic seismic loss endurance time method uncertaintypropagation

Detailed seismic risk analysis of electrical substation equipment using a reliability based approach

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earthquake engineering and engineering Vibration 2023年第2期22卷 495-511页

作者： Amir Ghah.e.ani Baghmisheh Milad Khodaei Ali Zare Feiz Abadi homayoon e.estekanchi Department of Civil engineering University of British ColumbiaVancouver V6T 2B8Canada Department of Civil engineering University of TabrizTabriz 51666Iran Department of Civil engineering Sharif University of TechnologyTehran 11155-9313Iran

This paper proposes a risk analysis framework for substation structures based on reliability *** though several risk assessment approaches have been developed for buildings,detailed risk analysis procedures for infrastructure components have been lacking in prior *** proposed framework is showcased by its application to a system of interconnected structures at a power substation in *** element models of structures are developed and validated in accordance with previous *** uncertainties in the material,mass,and geometric properties of structures are described by random variables that are input to the finite element *** artificial ground motion model is employed to comprehensively consider uncertainty in ground *** Carlo sampling is subsequently conducted on the library of probabilistic *** analysis resulted in the loss distribution in the life cycle of ***,the loss associated with six earthquake scenarios having specific magnitudes and return periods is *** application provides insight into the most vulnerable equipment in the considered ***,introduced risk measures can guide stakeholders to make risk-based decisions to optimize design or prioritize a retrofit of infrastructure components under conditions of uncertainty.

关键词： seismic risk reliability analysis infrastructure components loss estimation uncertainty

Free vibration and transient response of double curved beams connected by intermediate straight beams

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Applied Mathematics and Mechanics(english.e.ition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-TALOOKOLAeI h.GhANDVAR e.JUMAeV S.KhATIR T.CUONG-Le School of Mechanical engineering Babol Noshirvani University of Technology Department of Mechanical engineering Faculty of Engineering New Uzbekistan University University of Business and Science Center for engineering Application and Technology Solutions Ho Chi Minh City Open University

This paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. The strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. The curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. Subsequently, the natural frequencies and transient response of the system are determined. The accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANSYS, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

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碳纳米管纱的时间依赖电性能(英文)

新型炭材料 2015年第3期30卷 207-213页

作者： h.e. Misak S. Mall Air Force Institute of Technology Department of Aerospace engineering 2950 hobson Way Wright-Patterson AFB OH 45433-7765 USA Wichita State University Department of Meehanieal engineering 1845 Fairmount Wichita KS 67260-0133 USA

碳纳米管(CNTs)在电力转换领域具有潜在前景。本文表征碳纳米管纱随时间变化对电力的转换性能影响。通过建立I-V关系,结果表明存在3个区域,即线性、非线性和下降区域。线性区域表明呈现低且恒定电阻。当恒定电压处于I-V线性区域时,输出... 详细信息

碳纳米管(CNTs)在电力转换领域具有潜在前景。本文表征碳纳米管纱随时间变化对电力的转换性能影响。通过建立I-V关系,结果表明存在3个区域,即线性、非线性和下降区域。线性区域表明呈现低且恒定电阻。当恒定电压处于I-V线性区域时,输出电流强度不随时间而改变。然而,当恒定电压处于非线性区域时,电流强度以指数级下降后随时间而趋平。在恒电流测试下,电压仅在电流强度处于非线性区时增加。依赖时间的导电性能可通过短路来理解。短路发生在非线性区域的碳纳米管纱中炽热部位,会导致热性能降低。通过热图像、热重分析、扫描电镜和能谱分析等手段对碳纳米管纱进行分析。

关键词：碳纳米管纱电性能时间依赖铁球

Resonances-excitation Calculation Studies Investigation of △(3,3)in Ground State of ^(90)Zr Cold Finite heavy Nucleus at equilibrium and Under Large Compression

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Communications in Theoretical Physics 2011年第1期55卷 115-122页

作者： Mohammed h.e. Abu-Sei'leek Department of Physics Al-Jouf University

A non-relativistic microscopic mean field theory of finite nuclei is investigated where the nucleus is described as a collection of nucleons and delta resonances. The ground state properties of 90Zr nucleus have been investigated at equilibrium and large amplitude compression using a realistic effective baryon-baryon hamiltonian based on Reid Soft Core （RSC） potential. The sensitivity of the ground state properties is studied, such as binding energy, nuclear radius, radial density distribution, and single particle energies to the degree of compression. It is found that the most of increasing in the nuclear energy generated under compression is used to create the massive Δ particles. For 90Zr nucleus under compression at 2.5 times density of the normal nuclear density, the excited nucleons to Δ ＇s are increased sharply up to 14% of the total number of constituents. This result is consistent with the values extracted from relativistic heavy-ion collisions. The single particle energy levels are calculated and their behaviors under compression are examined too. A good agreement between results with.e.fective hamiltonian and the phenomenologieal shell model for the low lying single-particle spectra is obtained. A considerable reduction in compressibility for the nucleus, and softening of the equation of state with the inclusion of the Δ＇s in the nuclear dynamics are suggested by the results.

关键词： nuclear structure compressed finite nuclei Δ-resonance

A method for matching response spectra of endurance time excitations via the Fourier transform

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earthquake engineering and engineering Vibration 2020年第3期19卷 637-648页

作者： Mohammadreza Mashayekhi homayoon eestekanchi hassan Vafai Department of Civil engineering Sharif University of TechnologyTehranIran

The endurance time(eT)method is a dynamic analysis in which structures are subjected to intensifying excitations,also known as eT excitation functions(eTeF).The eT method is a tool for structural response *** main advantage of the eT method over conventional approaches is its much lower demand for computational *** concept of acceleration spectra is used in generating existing *** is expected that eTeF acceleration spectra increase consistently with time and remain proportional to a target *** unconstrained optimization is commonly used to generate *** new eTeFs is a complicated time-consuming mathematical *** the target acceleration spectrum changes,new eTeFs must be *** study intends to modify existing eTeFs to be compatible with a desired acceleration *** process,called spectral matching,obviates the need for using the complicated generating procedure in simulating new *** spectral matching is introduced in this paper for the first time.A Fourier-based method for eTeFs spectral matching is *** algorithm is then applied in a case *** are presented to prove the efficiency of the algorithm.

关键词： spectrum. excitation acceleration

Strengthening Cooperation Among Political Parties to Jointly Pursue the People's Wellbeing

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International Understanding 2021年第2期 1-6页

作者： h.e. Xi Jinping General Secretary of the Central Committee of The Communist Party of China And President of the People's Republic of China At the CPC and World Political Parties Summit Beijing

Keynote Address by *** Jinping General Secretary of the Central Committee of The Communist Party of China And President of the People’s Republic of China At the CPC and World Political Parties Summit Beijing,6 July 2021 Your excellencies leaders of political parties,Ladies and Gentlemen,Friends,It gives me great pleasure to join you,leaders of more than 500 political parties,political and other organisations from over 160 countries as well as the ten thousand and more representatives of political parties and various circles。

关键词： parties political Communist