检索结果-内蒙古大学图书馆

Consistent Multilevel RDT-ERA for Output-Only Ambient Modal Identification of Structures

INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS 2017年第9期17卷 1750106-1750106页

作者： Feng, Zhouquan Shen, Wenai Chen, Zhengqing Hunan Univ Coll Civil Engn Key Lab Wind & Bridge Engn Hunan Prov Changsha 410082 Hunan Peoples R China Huazhong Univ Sci & Technol Sch Civil Engn & Mech Wuhan 430074 Hubei Peoples R China

This paper presents an improved method called the consistent multilevel random decrement technique in conjunction with eigensystem realization algorithm (RDT-ERA) for modal parameter identification of linear dynamic systems using the ambient vibration data. The conventional RDT-ERA is briefly revisited first and the problem of triggering level selection in the RDT is thoroughly studied. Due to the use of a single triggering level by the conventional RDTERA, an inappropriate triggering level may produce poor random decrement (RD) functions, thereby yielding a poor estimate of modal parameters. In the proposed consistent multilevel RDTERA, multiple triggering levels are used and a consistency analysis is proposed to sift out the RD functions that deviate largely from the majority of the RD functions. Then the ERA is applied to the retained RD functions for modal parameter identification. Subsequently, a similar consistency analysis is conducted on the identi fied modal parameters to sift out the outliers. Finally, the final estimates of the modal parameters are calculated using weighted averaging with the weights set proportional to the number of RD segments extracted from the corresponding triggering levels. The proposed method is featured by the fact that the information from the signal is fully utilized using multiple triggering levels and the outliers are sifted out using consistency analysis, thus making the identi fied result more accurate and reliable. The eff effctiveness and accuracy of the method have been demonstrated in the examples using the simulated data and experimental data.

关键词： Modal identification random decrement technique eigensystem realization algorithm triggering level consistency analysis

来源：评论

学校读者我要写书评

暂无评论

System Identification of One Historical Bridge Using Dynamic Test Data

引用

ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2017年第9期42卷 4145-4155页

作者： Wu, Jie Yan, Quansheng Wu, Xiaoling South China Univ Technol Sch Civil Engn & Transportat Guangzhou 510640 Guangdong Peoples R China Univ Kansas Dept Civil Environm & Architectural Engn Lawrence KS 66049 USA Guangdong Polytech Coll Dept Elect & Mech Engn Guangzhou 510520 Guangdong Peoples R China

Obtaining accurately estimation of modal parameters from dynamic test data is an essential part for analyzing civil engineering structures. A set of dynamic field tests were conducted at a historic bridge. These tests provided an opportunity to identify the modal properties of the bridge in current condition. The system identification of the bridge was performed by using two different methods: (1) peak picking method and (2) eigensystem realization algorithm. By analyzing the output-only data, the natural frequencies in the vertical, lateral and torsional directions were identified. After comparing the data between measurements and the finite element model, the identified parameters using these system identification methods are found to be considerable for each type of tests. And through eigensystem realization algorithm, much more comprehensive results were obtained than peak picking method.

关键词： System identification Output only Peak picking method eigensystem realization algorithm FE model

来源：评论

学校读者我要写书评

暂无评论

Frequency domain approach for transonic aerodynamic modelling applied to a viscous aircraft model 55

Frequency domain approach for transonic aerodynamic modellin...

引用

55th AIAA Aerospace Sciences Meeting

作者： Poncet-Montanges, Adrien Cooper, J.E. Jones, D. Gaitonde, A.L. Lemmens, Y. University of Bristol Queens Building University Walk BristolBS8 1TH United Kingdom Department of Aerospace Engineering University of Bristol Queens Building University Walk BristolBS8 1TH United Kingdom Digital Factory Division Simulation & Test solutions Siemens Industry Software Leuven Belgium

ISBN: (数字)9781624104473

ISBN: (纸本)9781624104473

This work introduces a method for the construction of a reduced order model in the frequency domain. With input data obtained with the TAU linearized frequency domain solver, the reduced order model shows a strong ability to reconstruct the full order frequency response of a viscous aircraft configuration. Reduced order models have been successfully created for different strips on the wing, the fuselage and the horizontal plane. © 2017 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

关键词： Frequency Response Aircraft Configurations Aerodynamic Coefficients Singular Value Decomposition Hankel Singular Value Model Order Reduction Pressure Coefficient eigensystem realization algorithm Angle of Attack Aeronautics

来源：评论

学校读者我要写书评

暂无评论

New accuracy indicator to quantify the true and false modes for eigensystem realization algorithm

引用

STRUCTURAL ENGINEERING AND MECHANICS 2010年第5期34卷 625-634页

作者： Wang, Shuqing Liu, Fushun Ocean Univ China Coll Engn Qingdao 266100 Peoples R China

The objective of this paper is to apply a new proposed accuracy indicator to quantify the true and false modes for eigensystem realization algorithm using output-based responses. First, a discrete mass-spring system and a simply supported continuous beam were modelled using finite element method. Then responses are simulated under random excitation. Natural Excitation Technique using only response measurements is applied to compute the impulse responses. eigensystem realization algorithm is employed to identify the modal parameters on the simulated responses. A new accuracy indicator, Normalized Occurrence Number-NON, is developed to quantitatively partition the realized modes into true and false modes so that the false portions can be disregarded. Numerical simulation demonstrates that the new accuracy indicator can determine the true system modes accurately.

关键词： modal identification eigensystem realization algorithm accuracy indicator normalized occurrence number

来源：评论

学校读者我要写书评

暂无评论

Modal parameter identification for a roof overflow powerhouse under ambient excitation

引用

Water Science and Engineering 2016年第1期9卷 67-80页

作者： Yan Zhang Ji-jian Lian Fang Liu State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100038China

Modal parameter identification is a core issue in health monitoring and damage detection for hydraulic structures. For a roof overflow hydropower station with a bulb tubular unit under ambient excitation, a complex unit-powerhouse-dam coupling vibration system increases the difficulties of modal parameter identification. In this study, in view of the difficulties of modal order determination and the noise jamming caused by ambient excitation, along with false mode identification and elimination problems, the ensemble empirical mode decomposition （EEMD） method was used to decrease noise, the singular entropy increment spectrum was used to determine system order, and multiple criteria were used to eliminate false modes. The eigensystem realization algorithm （ERA） and stochastic subspace identification （SSI） method were then used to identify modal parameters. The results show that the relative errors of frequencies in the first four modes were within 10% for the ERA method, while those of SSI were over 10% in the second and third modes. Therefore, the ERA method is more appropriate for identifying the structural modal parameters for this particular powerhouse layout.

关键词： Hydraulic structure Order determination Ensemble empirical mode decomposition Singular entropy eigensystem realization algorithm Bulb tubular unit

来源：评论

学校读者我要写书评

暂无评论

On-orbit identification of flexible parameters of spacecraft

引用

PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART K-JOURNAL OF MULTI-BODY DYNAMICS 2016年第2期230卷 191-206页

作者： Xie, Yong Liu, Pan Cai, Guo-Ping Shanghai Jiao Tong Univ Dept Engn Mech State Key Lab Ocean Engn 800 Dong Chuan Load Shanghai 200240 Peoples R China

This paper studies the on-orbit identification of flexible parameters of spacecraft using a typical spacecraft as research object. First, the coupled dynamic equation of the system is established with the Lagrange method and the model order of the solar array is reduced using the inertia complete criterion. Then, the particle swarm optimization is adopted to determine the optimal positions of acceleration sensors on the solar array. Finally, the observer/Kalman filter identification and eigensystem realization algorithm are applied to identify the flexible parameters of the system. In the simulations, three types of external excitations, including white noise, sine and impulse, are considered as system input, respectively. Simulation results indicate that the presented method in this paper is effective in identifying the flexible parameters of the spacecraft.

关键词： Spacecraft flexible parameter on-orbit identification observer Kalman filter identification eigensystem realization algorithm

来源：评论

学校读者我要写书评

暂无评论

A Novel Method to Correlate a Rocket Launcher Finite Element Model Using Experimental Modal Test Measurements and Identification algorithms 34

引用

34th IMAC Conference and Exposition on Structural Dynamics

作者： Couch, Ronald N. Radcliffe, Eliott J. Caldwell, Rickey A. Johns Hopkins Univ Appl Phys Lab 11100 Johns Hopkins Rd Laurel MD 20723 USA

ISBN: (纸本)9783319300870;9783319300863

The structural dynamics of a launcher system used to guide the initial trajectory of target test missiles is considered. Launcher induced body rates alter the trajectories of target vehicles at egress which can detrimentally affect the successful execution of flight test missions. As a result, flight mission analysts must have the capability to accurately reproduce the dynamic response of the launcher system to evaluate its effect on launch vehicle egress. Accurately reproducing this response requires a high fidelity finite element model that is correlated to modal survey test data. An experimental modal survey of a modified Nike-Hercules launch system is conducted and modal parameters are determined using conventional and output-only methodologies. A model correlation procedure is proposed and utilized that incorporates these experimentally determined modal parameters in conjunction with a set of correlation criteria to improve the accuracy of a high-fidelity launcher finite element model. After several iterations of the model correlation procedure, the model is able to accurately reproduce the dominant dynamic behaviors observed in the modal survey tests, especially at the key location of the launcher tip. This approach provides a basis for future launcher simulation and modeling efforts.

关键词： Modal survey Finite element model correlation eigensystem realization algorithm

来源：评论

学校读者我要写书评

暂无评论

On the Output-Only Vibration-Based Damage Detection of Frame Structures 1

引用

34th IMAC Conference and Exposition on Structural Dynamics

作者： Bernagozzi, Giacomo Landi, Luca Diotallevi, Pier Paolo Univ Bologna Dept DICAM Viale Risorgimento 2 I-40136 Bologna Italy

ISBN: (数字)9783319299563

ISBN: (纸本)9783319299563;9783319299556

The present work aims at applying and comparing some methods for vibration-based damage detection of civil structures starting from ambient vibration data. The analyzed procedures are based on a dynamic identification of the modal parameters that is performed in output-only conditions;this is a typical situation that occurs when structural health monitoring strategies are applied to civil structures. The here investigated damage-sensitive features are the modal parameters, the modal flexibility matrix and the damage-induced deflection, due to unitary inspection loads, of the identified structure;possible variations in these parameters can be adopted in order to detect, localize and quantify the damage. A damaged condition is analytically simulated through a stiffness reduction in the elements of a RC shear-type plane frame. The output-only modal identification is performed through the eigensystem realization algorithm, combined with the Random Decrement technique, on the simulated responses due to a white noise ground motion of both the undamaged and the damaged structures. At the end, the effectiveness of the different identified damage features is evaluated and the accuracy related to the identified modifications, due to damage, is determined through a comparison with the initially assumed variations in the structural model.

关键词： Output-only modal identification eigensystem realization algorithm Structural health monitoring Vibration-based damage detection RC frame

来源：评论

学校读者我要写书评

暂无评论

Nonlinear Aeroelastic Analysis of Control Surface with Freeplay Using Computational-Fluid-Dynamics-Based Reduced-Order Models

引用

JOURNAL OF AIRCRAFT 2015年第2期52卷 569-583页

作者： Morino, Hiroyuki Obayashi, Shigeru Mitsubishi Aircraft Corp Aircraft Integrat Dept Minato Ku Nagoya Aichi 4558555 Japan Tohoku Univ Inst Fluid Sci Aoba Ku Sendai Miyagi 9808577 Japan

A computational-fluid-dynamics-based aeroelastic analysis method is proposed to simulate control-surface limitcycle oscillation (LCO) induced by freeplay gap. The present method is based on the previously proposed aeroelastic reduced-order model (ROM), in which an unsteady aerodynamic state-space model is generated from aerodynamic responses to step excitation of individual mode using the eigensystem realization algorithm, and connected to a structural dynamic state-space model within the MATLAB/SIMULINK environment. The aeroelastic ROM is extended to treat structural nonlinearity due to the control-surface freeplay by generating an additional feedback line of generalized residual forces in the SIMULINK model. To reduce the problem size and the computation time, a fictitious-mass modal approach is used, which can afford the possible local change of stiffness. The present method is first validated for its capability to simulate aeroelastic responses of a regional-jet horizontal-tail (HT) model without freeplay, and shows good prediction of flutter characteristics measured in the transonic flutter wind-tunnel testing. The present method is then applied to the HT model with the elevator freeplay gaps. Although there are some differences between the computed and measured limit-cycle-oscillation ranges, the present method well predicts the nonlinear limit-cycle-oscillation behavior in its amplitude and frequency measured in the test, and shows promise toward accurate prediction of control-surface LCO due to its freeplay gap.

关键词： Aeroelastic Analysis CFD Simulation Control Surfaces Structural Nonlinearities Transonic Wind Tunnel eigensystem realization algorithm MATLAB Aerodynamic Simulation Elevator Deflection Structural Finite Elements

来源：评论

学校读者我要写书评

暂无评论

EVALUATION OF DAMPING ESTIMATES IN THE PRESENCE OF CLOSELY SPACED MODES USING OPERATIONAL MODAL ANALYSIS TECHNIQUES 6

EVALUATION OF DAMPING ESTIMATES IN THE PRESENCE OF CLOSELY S...

引用

6th International Operational Modal Analysis Conference (IOMAC)

作者： Bajric, Anela Brincker, Rune Thons, Sebastian Tech Univ Denmark Dept Civil Engn Lyngby Denmark Aarhus Univ Dept Engn DK-8000 Aarhus C Denmark

ISBN: (纸本)9788416046805

The Operational Modal Analysis (OMA) techniques provide in most cases reasonably accurate estimates of structural frequencies and mode shapes. They are however known to produce erroneous structural damping estimates, which are presumably thought to be due to inherent random- or bias errors that have varying significance for different techniques. This paper evaluates the sensitivity of damping estimates of closely spaced modes for two existing OMA techniques derived in the time and frequency domain;namely eigensystem realization algorithm (ERA) and Frequency Domain Decomposition (FDD). The evaluation is based on identification using random response from white noise loading of a three degree-of-freedom (3DOF) system numerically established from specified modal parameters for a range of natural frequencies. The numerical model provides comparisons of the effectiveness of damping estimation for a variety of damping levels, signal noise and the sensitivity to closely spaced modes. It is shown that FDD has a tendency to overestimate damping due to leakage in the estimated spectral density function and it is a more sensitive technique to system changes than the ERA. The accuracy of damping estimates converges with increased frequency of the system, which is mainly a result of the problematic regions in the correlation function estimation. These regions cause amplification of the damping estimation errors at higher levels of damping. This emphasizes the importance of correctly estimating the correlation function and spectral density as bias will potentially result in large errors in the estimation of highly damped systems. It is concluded that damping estimated are sensitive to closely spaced modes. In addition, it is found that two closely spaced modes will also disturb the estimation of damping of the remaining modes in the system.

关键词： Operational Modal Analysis structural damping eigensystem realization algorithm Frequency Domain Decomposition closely spaced modes

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：