Search | Engineering

订阅投稿

首页工程期刊工程焦点工程成就工程前沿关于我们 English

资源类型

期刊论文 1678

会议视频 30

会议信息 2

年份

2024 1

2023 80

2022 123

2021 121

2020 85

2019 109

2018 99

2017 96

2016 70

2015 92

2014 90

2013 73

2012 84

2011 74

2010 74

2009 59

2008 82

2007 94

2006 41

2005 26

展开︾

关键词

风险分析 9

能源 8

分析 4

可持续发展 4

对策 4

影响因素 4

数值模拟 4

隧道 4

ANSYS 3

农业科学 3

抗击疫情 3

数值分析 3

环境 3

营养健康 3

裂缝 3

2035年 2

BNLAS 2

COVID-19 2

DX桩 2

展开︾

检索范围：

排序：展示方式：

Time-domain and frequency-domain approaches to identification of bridge flutter derivatives

Zhengqing CHEN

《结构与土木工程前沿（英文）》 2009年第3卷第2期页码 173-179 doi: 10.1007/s11709-009-0034-1

摘要： Flutter derivatives are essential for flutter analysis of long-span bridges, and they are generally identified from the vibration testing data of a sectional model suspended in a wind tunnel. Making use of the forced vibration testing data of three sectional models, namely, a thin-plate model, a nearly streamlined model, and a bluff-body model, a comparative study was made to identify the flutter derivatives of each model by using a time-domain method and a frequency-domain method. It was shown that all the flutter derivatives of the thin-plate model identified with the frequency-domain method and time-domain method, respectively, agree very well. Moreover, some of the flutter derivatives of each of the other two models identified with the two methods deviate to some extent. More precisely, the frequency-domain method usually results in smooth curves of the flutter derivatives. The formulation of time-domain method makes the identification results of flutter derivatives relatively sensitive to the signal phase lag between vibration state vector and aerodynamic forces and also prone to be disturbed by noise and nonlinearity.

关键词： long-span bridges wind-induced vibration flutter derivatives forced vibration test time-domain method frequency-domain method

HTML PDF 收藏

基于频域的多变量广义预测控制（MIMO-GPC）稳定性分析

孙青林,陈增强,袁著祉

《中国工程科学》 2004年第6卷第10期页码 39-44

摘要：

提出了基于频域的多变量广义预测控制（MIMO-GPC）稳定性分析方法，推导了MIMO-GPC的闭环反馈结构，给出了基于闭环特征多项式的MIMO-GPC的稳定性判据和奈奎斯特稳定性判据。这些判据可作为MIMO-GPC控制器参数设计的重要依据。

关键词：多变量广义预测控制频域分析稳定性判据

HTML PDF 收藏

Frequency domain a9ctive vibration control of a flexible plate based on neural networks

Jinxin LIU, Xuefeng CHEN, Zhengjia HE

《机械工程前沿（英文）》 2013年第8卷第2期页码 109-117 doi: 10.1007/s11465-013-0252-z

摘要：

A neural-network (NN)-based active control system was proposed to reduce the low frequency noise radiation of the simply supported flexible plate. Feedback control system was built, in which neural network controller (NNC) and neural network identifier (NNI) were applied. Multi-frequency control in frequency domain was achieved by simulation through the NN-based control systems. A pre-testing experiment of the control system on a real simply supported plate was conducted. The NN-based control algorithm was shown to perform effectively. These works lay a solid foundation for the active vibration control of mechanical structures.

关键词： active vibration control (AVC) neural network (NN) low frequency noise frequency domain control multi-frequency control

HTML PDF 收藏

基于频域的PID广义预测控制器的鲁棒性分析

王繁珍,陈增强,姚向峰,袁著祉

《中国工程科学》 2006年第8卷第10期页码 66-70

摘要：

推导了PID广义预测控制器(PID-GPC)的闭环反馈结构, 采用小增益定理获得了存在建模误差(MPM)情况下PID-GPC鲁棒稳定的一个充分条件。然后在频域内分析了PID-GPC控制器的参数选择对其鲁棒性的影响。

关键词：预测控制鲁棒性频域小增益定理 PID控制

HTML PDF 收藏

An efficient stochastic dynamic analysis of soil media using radial basis function artificial neural

P. ZAKIAN

《结构与土木工程前沿（英文）》 2017年第11卷第4期页码 470-479 doi: 10.1007/s11709-017-0440-8

摘要： Since a lot of engineering problems are along with uncertain parameters, stochastic methods are of great importance for incorporating random nature of a system property or random nature of a system input. In this study, the stochastic dynamic analysis of soil mass is performed by finite element method in the frequency domain. Two methods are used for stochastic analysis of soil media which are spectral decomposition and Monte Carlo methods. Shear modulus of soil is considered as a random field and the seismic excitation is also imposed as a random process. In this research, artificial neural network is proposed and added to Monte Carlo method for sake of reducing computational effort of the random analysis. Then, the effects of the proposed artificial neural network are illustrated on decreasing computational time of Monte Carlo simulations in comparison with standard Monte Carlo and spectral decomposition methods. Numerical verifications are provided to indicate capabilities, accuracy and efficiency of the proposed strategy compared to the other techniques.

关键词： stochastic analysis random seismic excitation finite element method artificial neural network frequency domain analysis Monte Carlo simulation

HTML PDF 收藏

H_∞ control in the frequency domain for a semi-active floor isolation system

Yundong SHI, Tracy C BECKER, Masahiro KURATA, Masayoshi NAKASHIMA

《结构与土木工程前沿（英文）》 2013年第7卷第3期页码 264-275 doi: 10.1007/s11709-013-0214-x

摘要： A floor isolation system installed in a single floor or room in a fixed base structure is designed to protect equipment. With this configuration, the input motions to the floor isolation from the ground motions are filtered by the structure, leaving the majority of the frequency content of the input motion lower than the predominant frequency of the structure. The floor isolation system should minimize the acceleration to protect equipment; however, displacement must also be limited to save floor space, especially with long period motion. Semi-active control with an control was adopted for the floor isolation system and a new input shaping filter was developed to account for the input motion characteristics and enhance the effectiveness of the control. A series of shake table tests for a semi-active floor isolation system using rolling pendulum isolators and a magnetic-rheological damper were performed to validate the control. Passive control using an oil damper was also tested for comparison. The test results show that the control effectively reduced acceleration for short period motions with frequencies close to the predominant frequency of the structure, as well as effectively reduced displacement for long period motions with frequencies close to the natural frequency of the floor isolation system. The control algorithm proved to be more advantageous than passive control because of its capacity to adjust control strategies according to the different motion frequency characteristics.

关键词： semi-active floor isolation H_∞ control MR damper shaping filter shaking table test

HTML PDF 收藏

基于钻头运动诱发套管头振动信号检测的井眼防碰监测方法

何保生,刘刚,王平双,文敏

《中国工程科学》 2011年第13卷第5期页码 74-78

摘要：

针对海上加密调整井的井眼防碰问题，设计了一种井筒防碰地面监测预警系统，并进行了现场应用。系统利用加速度传感器监测通过套管传输到套管头上的钻头振动信号，利用数据采集、信号滤波放大和专门编制的监测软件记录分析传感器采集的振动信号，通过对信号的时域、频域分析，确定信号特征与井间相对距离的关系，识别钻头对风险井套管的趋近或碰撞。应用结果表明，该系统能有效感知通过地层、套管传输到套管头的钻头振动信号，并能识别出钻头对风险邻井的趋近，验证了系统在设计理论和方法上的可行性，为加密调整井的井眼防碰、保证钻井安全提供了一种有效的手段。

关键词：调整井防碰风险井振动信号时域分析频域分析

HTML PDF 收藏

A frequency error estimation for isogeometric analysis of Kirchhoff–Love cylindrical shells

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0006-x

摘要： A frequency error estimation is presented for the isogeometric free vibration analysis of Kirchhoff–Love cylindrical shells using both quadratic and cubic basis functions. By analyzing the discrete isogeometric equations with the aid of harmonic wave assumption, the frequency error measures are rationally derived for the quadratic and cubic formulations for Kirchhoff–Love cylindrical shells. In particular, the governing relationship of the continuum frequency for Kirchhoff–Love cylindrical shells is naturally embedded into the frequency error measures without the need of explicit frequency expressions, which usually are not trivial for the shell problems. In accordance with these theoretical findings, the 2nd and 4th orders of frequency accuracy are attained for the isogeometric schemes using quadratic and cubic basis functions, respectively. Numerical results not only thoroughly verify the theoretical convergence rates of frequency solutions, but also manifest an excellent magnitude match between numerical and theoretical frequency errors for the isogeometric free vibration analysis of Kirchhoff–Love cylindrical shells.

关键词： isogeometric analysis Kirchhoff–Love cylindrical shell free vibration frequency error convergence

HTML PDF 收藏

Optimum lateral extent of soil domain for dynamic SSI analysis of RC framed buildings on pile foundations

Nishant SHARMA, Kaustubh DASGUPTA, Arindam DEY

《结构与土木工程前沿（英文）》 2020年第14卷第1期页码 62-81 doi: 10.1007/s11709-019-0570-2

摘要： This article describes a novel approach for deciding optimal horizontal extent of soil domain to be used for finite element based numerical dynamic soil structure interaction (SSI) studies. SSI model for a 12 storied building frame, supported on pile foundation-soil system, is developed in the finite element based software framework, OpenSEES. Three different structure-foundation configurations are analyzed under different ground motion characteristics. Lateral extent of soil domain, along with the soil properties, were varied exhaustively for a particular structural configuration. Based on the reduction in the variation of acceleration response at different locations in the SSI system (quantified by normalized root mean square error, ), the optimum lateral extent of the soil domain is prescribed for various structural widths, soil types and peak ground acceleration levels of ground motion. Compared to the past studies, error estimation analysis shows that the relationships prescribed in the present study are credible and more inclusive of the various factors that influence SSI. These relationships can be readily applied for deciding upon the lateral extent of the soil domain for conducting precise SSI analysis with reduced computational time.

关键词： soil structure interaction optimum lateral extent of soil domain length multi-storyed framed building pile foundation OpenSEES L-K boundaries dynamic analysis

HTML PDF 收藏

Analysis of frequency characteristics of compliant mechanisms

WANG Wenjing, YU Yueqing

《机械工程前沿（英文）》 2007年第2卷第3期页码 267-271 doi: 10.1007/s11465-007-0046-2

摘要： Much work is needed for a further study on the dynamic analysis of compliant mechanisms to improve their performance and operational accuracy. This paper uses the finite element method to develop a dynamic equation of the compliant mechanism. Natural frequencies and modes are derived. Using the differentials of a stiffness matrix to design parameters, a method for calculating the sensitivity of natural frequency is presented. The numerical simulation results indicate that the design parameters have an impact on the frequency characteristics of the compliant mechanisms and the proposed method is more accurate and convenient for analyzing frequency characteristics.

关键词： compliant mechanisms convenient sensitivity work analysis

HTML PDF 收藏

Improved numerical method for time domain dynamic structure-foundation interaction analysis based on

DU Jianguo, LIN Gao

《结构与土木工程前沿（英文）》 2008年第2卷第4期页码 336-342 doi: 10.1007/s11709-008-0054-2

摘要： Based on the reduced set of base function in scaled boundary finite element method (SBFEM), an improved time domain numerical approach for the dynamic structure-foundation interaction analysis was proposed. With reasonable choice of the number of base functions, the degrees of freedom on the structure-foundation interface were reduced and the associated computation for the calculation of convolution integral was greatly reduced. The results of this proposed approach applied to the calculation of a gravity dam and an arch dam. The acceleration frequency response functions were calculated and the influences affected by different reduced set of base functions as well as full set were compared. It was found that a higher degree of reduced set of base functions resulted in a significant increase of computational efficiency but a little bit of loss in accuracy. When the reduced set was decreased by 60%, the efficiency may be increased to up to five times, while the loss of accuracy of peak value of response will be less than 4%. It may be concluded that the proposed approach is suitable for large-scale structure-foundation interaction analysis.

关键词： structure-foundation interface computational efficiency different suitable numerical approach

HTML PDF 收藏

长寿命路面疲劳寿命预测的频域分析方法

魏保立,郭成超,崔璨

《中国工程科学》 2017年第19卷第6期页码 80-85 doi: 10.15302/J-SSCAE-2017.06.012

摘要：

笔者分别从沥青路面和水泥混凝土路面两个方面分析了路面疲劳寿命预测的相关方法。重点对疲劳寿命预测的频域分析方法进行了较为详细的分析，结合车辆–道路耦合振动系统模型，对路面不平整引起的车辆与道路之间的随机振动进行了分析，指出车辆–道路耦合振动的随机功率谱密度是进行路面疲劳寿命预测的一种手段和方法，并提出了相应的预测步骤，旨在为长寿命路面的设计和性能评价提供参考。

关键词：长寿命路面疲劳寿命预测随机振动功率谱密度

HTML PDF 收藏

心电图信号的频域分析

涂承媛,曾衍钧,李树信

《中国工程科学》 2002年第4卷第12期页码 66-70

摘要：

提出了一种简便有效的、由心电图（ECG）曲线提取QRS-T复合波的新方法，从而获得P波（当房颤未发生时）或f波（当房颤时）；利用功率谱、自相关、互相关等信号处理技术，对它进行了处理和分析，特别是，比较了未房颤时和发生房颤时的相关信息的显著差别。

关键词：心电图（ECG） QRS-T复合波 P波房颤波（f波）频数直方图功率谱自相关互相关

HTML PDF 收藏

Capacity limitation of nuclear units in grid based on analysis of frequency regulation

Yiping DAI, Pan JIANG, Lin GAO, Weimin KAN, Xiaoqing XIAO, Ge JIN

《能源前沿（英文）》 2012年第6卷第2期页码 148-154 doi: 10.1007/s11708-012-0174-1

摘要： The increasing capacity of nuclear units in power grid poses threat to system stability and security. Load disturbance may cause overspeed of the units and trigger the overspeed protection controller (OPC). Repeating actions of valves have a strong impact on the security of the equipment and may result in a collapse of the power system. Based on the analysis of frequency regulation, mathematic models for nuclear units in the grid are established in this paper to simulate the dynamic process when load disturbance occurs. The critical action of the OPC is proposed as the constraint of safe operation for the units. The relationship between different styles of frequency regulation and the allowable capacity of the nuclear units in the grid is discussed. This research can help to estimate the capacity limitation of nuclear units in the grid.

关键词： nuclear units capacity overspeed primary frequency control (PFC) second frequency control (SFC)

HTML PDF 收藏

Meta-analysis of the diagnostic efficiency of frequency-doubling technology for primary glaucoma

LIU Ting, HE Xiangge

《医学前沿（英文）》 2007年第1卷第1期页码 109-114 doi: 10.1007/s11684-007-0021-7

摘要： The overall diagnostic capabilities and utility of frequency-doubling technology (FDT) in patients with primary glaucoma, which was diagnosed by standard automated perimetry (SAP) and/or optic disc appearance as the gold standard, were assessed. A comprehensive electric retrieval in MEDLINE, EMBASE, Cochrane Library, BIOSIS, Previews, HMIC, IPA, OVID, CNKI, CBMdisc, VIP information, CMCC, CCPD, SSreader, 21dmedia and manual retrieval in related textbooks, journals, congress articles and their references at home and abroad were performed to identify relevant articles in English or Chinese. The corresponding references were retrieved by means of electric retrieval and manual retrieval from different databases or materials. Criteria for inclusion or exclusion were established according to validity criteria for diagnostic studies published by the Cochrane Methods Group on Screening and Diagnostic Tests. The quality of the included articles was then assessed and characteristics were extracted. Statistical analysis was performed with Meta Test version 0.6 software to test the heterogeneity of the included articles. The appropriate effects model was selected to calculate pooled weighted sensitivity and specificity. Summary receiver operating characteristic (SROC) curve was drawn and the area under the curve (AUC) was calculated. Finally, sensitivity analysis was performed. Twenty-one studies out of 206 retrieved articles were included, with a total of 3172 patients. The reported sensitivity of FDT ranged from 0.51 to 1.00, and specificity from 0.58 to 1.00. The pooled weighted sensitivity and specificity of FDT with 95% confidence intervals (95% CI) after correction for standard error were 0.86 (0.80 0.90) and 0.87 (0.81 0.91), respectively. The AUC of SROC was 93.01%. Sensitivity analysis demonstrated no disproportionate influences of individual studies. The included articles are of good quality and FDT can be a highly efficient diagnostic test for primary glaucoma based on Meta-analysis.

关键词： inclusion sensitivity analysis correction specificity appropriate