检索结果-南通市图书馆

Deflection amplification factor for estimating seismic lateral deformations of RC frames

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2015年第2期14卷 373-384页

作者： Maryam Samimifar Asghar Vatani Oskouei Fayaz Rahimzadeh Rofooei department of civil Engineering Shahid Rajaee Teacher Training University department of civil Engineering Kharazmi University department of civil Engineering Sharif University of Technology

Different values have been assigned to the ratio of the defl ection amplifi cation factor(Cd) to the response modifi cation factor(R) for a specifi ed force-resisting system in the seismic design provisions while the same application is defi ned for it. An analytical study of the seismic responses of several reinforced concrete frames subjected to a suite of earthquake records performed in this research indicate that the stories’ overstrength and stiffness distribution along the structural height can affect local defl ections more than global ones. Therefore, the Cd/R ratio is calculated based on the ratio of both maximum inelastic to maximum elastic displacements and interstory drifts. Due to damage concentration in some specifi c stories, the defl ection amplifi cation factor calculated based on inelastic interstory drifts was larger than that of the inelastic displacements. Consequently, a minimum value of 1.0 is recommended for the Cd/R ratio in order to estimate maximum inelastic drifts. The ratio of inelastic to elastic displacement was generally found to increase slightly along the structural height for the studied RC models. In addition, it was detected that the story damage indices of the studied RC frames decrease when the inverted value of inelastic interstory drift ratios are increased through a(negative) power form.

关键词： deflection amplification factor nonlinear dynamic

Seismic behavior of breakwaters on complex ground by numerical tests:Liquefaction and post liquefaction ground settlements

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2018年第2期17卷 325-342页

作者： Gu Linlin Zhang Feng Bao Xiaohua Shi Zhenming Ye Guanlin Ling Xianzhang department of civil Engineering Qingdao University of Technology department of civil Engineering Nagoya Institute of Technology department of civil Engineering Shenzhen University department of Geotechnical Engineering Tongji University department of civil Engineering Shanghai Jiao Tong University

A large number of breakwaters have been constructed along coasts to protect humans and infrastructures from *** is a risk that foundation soils of these structures may liquefy,or partially liquefy during the earthquake preceding a tsunami,which would greatly reduce the structures’capacity to resist the *** is necessary to consider not only the soil’s liquefaction behavior due to earthquake motions but also its post-liquefaction behavior because this behavior will affect the breakwater’s capacity to resist an incoming *** this study,numerical tests based on a sophisticated constitutive model and a soil-water coupled finite element method are used to predict the mechanical behavior of breakwaters and the surrounding *** real breakwaters subjected to two different seismic excitations are examined through numerical *** simulation results show that,earthquakes affect not only the immediate behavior of breakwaters and the surrounding soils but also their long-term settlements due to post-earthquake consolidation.A soil profile with thick clayey layers beneath liquefied soil is more vulnerable to tsunami than a soil profile with only sandy ***,quantitatively evaluating the seismic behavior of breakwaters and surrounding soils is important for the design of breakwater structures to resist tsunamis.

关键词： breakwater settlement earthquake numerical test liquefaction

On the limitations of linear beams for the problems of moving mass-beam interaction using a meshfree method

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2012年第1期28卷 164-179页

作者： Keivan Kiani Ali Nikkhoo department of civil Engineering Islamic Azad University department of civil Engineering University of Science and Culture

This paper deals with the capabilities of linear and nonlinear beam theories in predicting the dynamic response of an elastically supported thin beam traversed by a moving mass. To this end, the discrete equations of motion are developed based on Lagrange＇s equations via reproducing kernel particle method （RKPM）. For a particular case of a simply supported beam, Galerkin method is also employed to verify the results obtained by RKPM, and a reasonably good agreement is achieved. Variations of the maximum dynamic deflection and bending moment associated with the linear and nonlinear beam theories are investigated in terms of moving mass weight and velocity for various beam boundary conditions. It is demonstrated that for majority of the moving mass velocities, the differences between the results of linear and nonlinear analyses become remarkable as the moving mass weight increases, particularly for high levels of moving mass velocity. Except for the cantilever beam, the nonlinear beam theory predicts higher possibility of moving mass separation from the base beam compared to the linear one. Furthermore, the accuracy levels of the linear beam theory are determined for thin beams under large deflections and small rotations as a function of moving mass weight and velocity in various boundary conditions.

关键词： Nonlinear beam theory Moving mass-beam in- teraction Euler-Bernoulli beam theory - Reproducing kernel particle method (RKPM) Galerkin method (GM)

Effects of fabric anisotropy on elastic shear modulus of granular soils

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2014年第2期13卷 269-278页

作者： Li Bo Zeng Xiangwu department of civil Engineering Wenzhou University department of civil Engineering Case Western Reserve University

The fabric anisotropy of a granular soil deposit can strongly infl uence its engineering properties and behavior. This paper presents the results of a novel experimental study designed to examine the effects of fabric anisotropy on smallstrain stiffness and its evolution with loading on the elastic shear modulus of granular materials under a K0 condition. Two primary categories of fabric anisotropy, i.e., deposition-induced and particle shape-induced, are investigated. Toyoura sand deposits with relative densities of 40% and 80% were prepared using deposition angles oriented at 0o and 90o. Piezoelectric transducers were used to obtain the elastic shear modulus in the vertical and horizontal directions(Gvh and Ghh). The measurements indicate distinct differences in the values of G with respect to the different deposition angles. Particle shapeinduced fabric anisotropy was examined using four selected sands. It was concluded that sphericity is a controlling factor dominating the small-strain stiffness of granular materials. The degree of fabric anisotropy proves to be a good indicatorin the characterization of stress-induced fabric evolution during loading and unloading stress cycles. The experimental data were used to calibrate an existing micromechanical model, which was able to represent the behavior of the granular material and the degree of fabric anisotropy reasonably well.

关键词： fabric anisotropy shape indicator shear wave velocity shear modulus

New lumped-mass-stick model based on modal characteristics of structures: development and application to a nuclear containment building

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2013年第2期12卷 307-317页

作者： Hwasung Roh Huseok Lee Jong Seh Lee department of civil Engineering Chonbuk National University department of civil and Environmental Engineering Hanyang University

In this study, a new lumped-mass-stick model （LMSM） is developed based on the modal characteristics of a structure such as eigenvalues and eigenvectors. The simplified model, named the ＂frequency adaptive lumped-massstick model,＂ hasonly a small number of stick elements and nodes to provide the same natural frequencies of the structure and is applied to a nuclear containment building. To investigate the numerical performance of the LMSM, a time history analysis is carried out on both the LMSM and the finite element model （FEM） for a nuclear containment building. A comparison of the results shows that the dynamic responses of the LMSM in terms of displacement and acceleration are almost identical to those of the FEM. In addition, the results in terms of floor response spectra at certain elevations are also in good agreement.

关键词： new lumped-mass-stick model frequency adaptive nuclear containment buildings seismic response floor response spectrum

Dynamic Interaction Analysis of Coupled Axial-Torsional-Lateral Mechanical Vibrations in Rotary Drilling Systems

在线全文

学校读者我要写书评

暂无评论

Structural Durability & Health Monitoring 2025年第1期19卷 77-103页

作者： Sabrina Meddah Sid Ahmed Tadjer Abdelhakim Idir Kong Fah Tee Mohamed Zinelabidine Doghmane Madjid Kidouche Applied Automation Laboratory Faculty of Hydrocarbons and ChemistryUniversity of BoumerdesBoumerdes35000Algeria Institute of Electrical and Electronic Engineering(IGEE) University of BoumerdesBoumerdes35000Algeria Laboratory of the Electrification of Industrial Enterprises University of BoumerdesBoumerdes35000Algeria Electrical Engineering department Mohamed Boudiaf University of M’silaM’sila28000Algeria department of civil and Environmental Engineering King Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Interdisciplinary Research Center for Construction and Building Materials King Fahd University of Petroleum&Minerals(KFUPM)Dhahran31261Saudi Arabia

Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and *** achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is *** study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling *** study speciﬁcally investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency *** events not only hinder the efﬁciency of drilling but also lead to exhaustion and harm to the system’s components since they are difﬁcult to be detected and controlled in real *** study investigates the dynamic interactions of these vibrations,speciﬁcally in their high-frequency modes,usingﬁeld data obtained from measurement while ***ﬁndings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem *** obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control ***,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect ***,by exploiting theseﬁndings,the assessment of structural resilience in rotary drilling systems can be ***,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efﬁciency of rotary drilling systems in the petroleum industry.

关键词： Rotary drilling systems mechanical vibrations structural durability dynamic interaction analysis ﬁeld data analysis

Interpretation of electrochemical impedance spectroscopy(EIS) circuit model for soils

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Central South University 2015年第11期22卷 4318-4328页

作者：韩鹏举张亚芬陈幼佳白晓红 department of civil Engineering Taiyuan University of Technology department of civil Engineering The Penn State University

Based on three different kinds of conductive paths in microstructure of soil and theory of electrochemical impedance spectroscopy(EIS), an integrated equivalent circuit model and impedance formula for soils were proposed, which contain 6 meaningful resistance and reactance parameters. Considering the conductive properties of soils and dispersion effects, mathematical equations for impedance under various circuit models were deduced and studied. The mathematical expression presents two semicircles for theoretical EIS Nyquist spectrum, in which the center of one semicircle is degraded to simply the equivalent model. Based on the measured parameters of EIS Nyquist spectrum, meaningful soil parameters can easily be determined. Additionally, EIS was used to investigate the soil properties with different water contents along with the mathematical relationships and mechanism between the physical parameters and water content. Magnitude of the impedance decreases with the increase of testing frequency and water content for Bode graphs. The proposed model would help us to better understand the soil microstructure and properties and offer more reasonable explanations for EIS spectra.

关键词： soil electrochemical impedance spectroscopy(EIS) e

Ensemble and optimized hybrid algorithms through Runge Kutta optimizer for sewer sediment transport modeling using a data pre-processing approach

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2023年第6期38卷 847-858页

作者： Enes Gul Mir Jafar Sadegh Safari Omer Faruk Dursun Gokmen Tayfur department of civil Engineering Inonu University department of civil Engineering Yasar University department of civil Engineering Izmir Institute of Technology

Uncontrolled sediment deposition in drainage and sewer systems raises unexpected maintenance *** this end,implementation of an accurate model relying on effective parameters involved is a reliable *** this study,three machine learning techniques,namely extreme learning machine(ELM),multilayer perceptron neural network(MLPNN),and M5P model tree(M5PMT);and three optimization approaches of Runge Kutta(RUN),genetic algorithm(GA),and particle swarm optimization(PSO) are applied for *** optimization and ensemble hybridization approaches are applied in the modeling *** the case of hybrid optimized models,the ELM and MLPNN models are hybridized with RUN,GA,and PSO algorithms to develop six hybrid models of ELM-RUN,ELM-GA,ELMPSO,MLPNN-RUN,MLPNN-GA,and *** hybrid models are developed through coupling the ELM and MLPNN models with the M5PMT *** data pre-processing approach is applied to find the best randomness characteristic of the utilized *** illustrate that the RUNbased hybrid models outperform the GA-and PSO-based *** the MLPNN-RUN and MLPNN-M5PMT hybrid models generate better results than their alternatives,MLPNN-M5PMT slightly outperforms MLPNN-RUN model with a coefficient of determination of 0.84 and a root mean square error of *** current study shows the superiority of the ensemble-based approach to the optimization *** investigation is needed by considering alternative optimization techniques to enhance sediment transport modeling.

关键词： Ensemble learning Hybrid model Machine learning Open channels Sediment transport Sewer pipes

Deflection modification factors of multistory buildings considering soil-structure interaction

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2015年第3期14卷 561-570页

作者： Farhad Abedi-Nik Faramarz Khoshnoudian department of civil Engineering SADRA Institute of Higher Education department of civil Engineering Amirkabir University of Technology

In this investigation,attempts are made to examine the effects of soil-structure interaction on the deflection modification factor of multistory buildings and to clarify the role of deformable soil on this factor.A comprehensive study is conducted to investigate the effect of inertial interaction on displacement demand ratios in soil-structure systems with different structural characteristics and various non-dimensional parameters,using a simplified interacting model.A two-step regression analysis of the nonlinear,dynamic computer simulation results obtained,leads to a reliable and accurate formula for predicting deflection modification factors that incorporate foundation *** results illustrate that the application of deflection modification factors derived from fixed-base structures can lead to unsafe evaluation of the structures on soft *** proposed formula provides a useful tool for design engineers to incorporate the effect of soil-structure interaction into the evaluation of structural deformations.

关键词： defl ection modifi cation factor multistory struct