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《机械工程前沿(英文)》 2014年 第9卷 第2期 页码 191-202 doi: 10.1007/s11465-014-0293-y
In present study, free vibration of cracked beams resting on two-parameter elastic foundation with elastically restrained ends is considered. Euler-Bernoulli beam hypothesis has been applied and translational and rotational elastic springs in each end considered as support. The crack is modeled as a mass-less rotational spring which divides beam into two segments. After governing the equations of motion, the differential transform method (DTM) has been served to determine dimensionless frequencies and normalized mode shapes. DTM is a semi-analytical approach based on Taylor expansion series that converts differential equations to recursive algebraic equations. The DTM results for the natural frequencies in special cases are in very good agreement with results reported by well-known references. Also, the DTM procedure yields rapid convergence beside high accuracy without any frequency missing. Comprehensive studies to analyze the effects of crack location, crack severity, parameters of elastic foundation and boundary conditions on dimensionless frequencies as well as effects of elastic boundary conditions on cracked beams mode shapes are carried out and some problems handled for first time in this paper. Since this paper deals with general problem, the derived formulation has capability for analyzing free vibration of cracked beam with every boundary condition.
关键词: free vibration cracked beam elastic foundation restrained ends differential transform method
《能源前沿(英文)》 页码 782-795 doi: 10.1007/s11708-023-0905-8
关键词: distributed photovoltaics (DPVs) cluster partitioning improved differential evolution algorithm voltage control consumption capacity of distributed photovoltaics
T. NGUYEN-THOI, A. TRAN-VIET, N. NGUYEN-MINH, T. VO-DUY, V. HO-HUU
《结构与土木工程前沿(英文)》 2018年 第12卷 第1期 页码 92-108 doi: 10.1007/s11709-016-0379-1
关键词: damage assessment damage locating vector method (DLV) differential evolution (DE) multiple damage location assurance criterion (MDLAC) mode shape error function
Solving nonlinear differential equations of Vanderpol, Rayleigh and Duffing by AGM
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《机械工程前沿(英文)》 2014年 第9卷 第2期 页码 177-190 doi: 10.1007/s11465-014-0288-8
In the present paper, three complicated nonlinear differential equations in the field of vibration, which are Vanderpol, Rayleigh and Duffing equations, have been analyzed and solved completely by Algebraic Method (AGM). Investigating this kind of equations is a very hard task to do and the obtained solution is not accurate and reliable. This issue will be emerged after comparing the achieved solutions by numerical method (Runge-Kutte 4th). Based on the comparisons which have been made between the gained solutions by AGM and numerical method, it is possible to indicate that AGM can be successfully applied for various differential equations particularly for difficult ones. The results reveal that this method is not only very effective and simple, but also reliable, and can be applied for other complicated nonlinear problems.
关键词: Algebraic Method (AGM) Angular Frequency Vanderpol Rayleigh Duffing
HHT-based crack identification method for start-up rotor
Bing LI, Chunlin ZHANG, Zhengjia HE
《机械工程前沿(英文)》 2012年 第7卷 第3期 页码 300-304 doi: 10.1007/s11465-012-0328-1
This paper presents a crack identification method for start-up rotor based on the Hilbert-Huang transform (HHT). With this method, the instantaneous frequency (IF) of each intrinsic mode function is obtained through the Hilbert transform, and the spectrum of IF is calculated accordingly. The influence of acceleration and crack depth on the rotor is analyzed through experiments. HHT is employed to detect the shallower crack, and is then tested during the start-up process of the rotor. The results of the experiment show that HHT is a better tool for crack detection than fast Fourier transform.
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《机械工程前沿(英文)》 2014年 第9卷 第2期 页码 130-141 doi: 10.1007/s11465-014-0298-6
Fault diagnosis of rolling element bearings requires efficient signal processing techniques. For this purpose, the performances of envelope detection with fast Fourier transform (FFT) and continuous wavelet transform (CWT) of vibration signals produced from a bearing with defects on inner race and rolling element, have been examined at low signal to noise ratio. Both simulated and experimental signals from identical bearings have been considered for the purpose of analysis. The bearings have been modeled as spring-mass-dashpot systems and the simulated signals have been obtained considering transfer functions for the bearing systems subjected to impulsive loads due to the defects. Frequency B spline wavelets have been applied for CWT and a discussion on wavelet selection has been presented for better effectiveness. Results show that use of CWT with the proposed wavelets overcomes the short coming of FFT while processing a noisy vibration signals for defect detection of bearings.
关键词: Fault detection spline wavelet continuous wavelet transform fast Fourier transform
Dynamics of structural systems with various frequency-dependent damping models
Li LI,Yujin HU,Weiming DENG,Lei LÜ,Zhe DING
《机械工程前沿(英文)》 2015年 第10卷 第1期 页码 48-63 doi: 10.1007/s11465-015-0330-5
The aim of this paper is to present the dynamic analyses of the system involving various damping models. The assumed frequency-dependent damping forces depend on the past history of motion via convolution integrals over some damping kernel functions. By choosing suitable damping kernel functions of frequency-dependent damping model, it may be derived from the familiar viscoelastic materials. A brief review of literature on the choice of available damping models is presented. Both the mode superposition method and Fourier transform method are developed for calculating the dynamic response of the structural systems with various damping models. It is shown that in the case of non-deficient systems with various damping models, the modal analysis with repeated eigenvalues are very similar to the traditional modal analysis used in undamped or viscously damped systems. Also, based on the pseudo-force approach, we transform the original equations of motion with nonzero initial conditions into an equivalent one with zero initial conditions and therefore present a Fourier transform method for the dynamics of structural systems with various damping models. Finally, some case studies are used to show the application and effectiveness of the derived formulas.
关键词: damping viscoelasticity dynamic analysis mode superposition method Fourier transform method
A reversibility-gain model for integer Karhunen-Loève transform design in video coding
Xing-guo ZHU,Lu YU
《信息与电子工程前沿(英文)》 2015年 第16卷 第10期 页码 883-891 doi: 10.1631/FITEE.1500071
关键词: Integer transform Karhunen-Loè ve transform (KLT) Integer-KLT Transform coding Video coding
Analytical and numerical investigation into the longitudinal vibration of uniform nanotubes
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《机械工程前沿(英文)》 2014年 第9卷 第2期 页码 142-149 doi: 10.1007/s11465-014-0292-z
In recent years, prediction of the behaviors of micro and nanostructures is going to be a matter of increasing concern considering their developments and uses in various engineering fields. Since carbon nanotubes show the specific properties such as strength and special electrical behaviors, they have become the main subject in nanotechnology researches. On the grounds that the classical continuum theory cannot accurately predict the mechanical behavior of nanostructures, nonlocal elasticity theory is used to model the nanoscaled systems. In this paper, a nonlocal model for nanorods is developed, and it is used to model the carbon nanotubes with the aim of the investigating into their longitudinal vibration. Following the derivation of governing equation of nanorods and estimation of nondimensional frequencies, the effect of nonlocal parameter and the length of the nanotube on the obtained frequencies are studied. Furthermore, differential quadrature method, as a numerical solution technique, is used to study the effect of these parameters on estimated frequencies for both classical and nonlocal theories.
关键词: continuum theory differential quadrature method nanorod longitudinal vibration
M.R. AKBARI,D.D. GANJI,A.R. AHMADI,Sayyid H. Hashemi KACHAPI
《机械工程前沿(英文)》 2014年 第9卷 第1期 页码 58-70 doi: 10.1007/s11465-014-0289-7
In the current paper, a simplified model of Tower Cranes has been presented in order to investigate and analyze the nonlinear differential equation governing on the presented system in three different cases by Algebraic Method (AGM). Comparisons have been made between AGM and Numerical Solution, and these results have been indicated that this approach is very efficient and easy so it can be applied for other nonlinear equations. It is citable that there are some valuable advantages in this way of solving differential equations and also the answer of various sets of complicated differential equations can be achieved in this manner which in the other methods, so far, they have not had acceptable solutions. The simplification of the solution procedure in Algebraic Method and its application for solving a wide variety of differential equations not only in Vibrations but also in different fields of study such as fluid mechanics, chemical engineering, etc. make AGM be a powerful and useful role model for researchers in order to solve complicated nonlinear differential equations.
关键词: Algebraic Method (AGM) tower crane oscillating system angular frequency
Analytical method of capsizing probability in the time domain for ships in the random beam seas
LIU Liqin, TANG Yougang, LI Hongxia
《结构与土木工程前沿(英文)》 2007年 第1卷 第3期 页码 361-366 doi: 10.1007/s11709-007-0048-5
关键词: different survival probability different significant nonlinear differential narrowband
Tuned reactive power dispatch through modified differential evolution technique
S. BISWAS (RAHA), N. CHAKRABORTY
《能源前沿(英文)》 2012年 第6卷 第2期 页码 138-147 doi: 10.1007/s11708-012-0188-8
关键词: reactive power dispatch (RPD) modified differential evolution (MDE) differential evolution algorithm with localizations around the best vector (DELB)
Review of MEMS differential scanning calorimetry for biomolecular study
Shifeng YU, Shuyu WANG, Ming LU, Lei ZUO
《机械工程前沿(英文)》 2017年 第12卷 第4期 页码 526-538 doi: 10.1007/s11465-017-0451-0
Differential scanning calorimetry (DSC) is one of the few techniques that allow direct determination of enthalpy values for binding reactions and conformational transitions in biomolecules. It provides the thermodynamics information of the biomolecules which consists of Gibbs free energy, enthalpy and entropy in a straightforward manner that enables deep understanding of the structure function relationship in biomolecules such as the folding/unfolding of protein and DNA, and ligand bindings. This review provides an up to date overview of the applications of DSC in biomolecular study such as the bovine serum albumin denaturation study, the relationship between the melting point of lysozyme and the scanning rate. We also introduce the recent advances of the development of micro-electro-mechanic-system (MEMS) based DSCs.
关键词: differential scanning calorimetry biomolecule MEMS thermodynamic
基于多智能体微分博弈的数据驱动协同一致控制 Research Article
石宇1,化永朝2,于江龙1,董希旺1,2,任章1
《信息与电子工程前沿(英文)》 2022年 第23卷 第7期 页码 1043-1056 doi: 10.1631/FITEE.2200001
标题 作者 时间 类型 操作
Semi-analytical approach for free vibration analysis of cracked beams resting on two-parameter elastic foundation with elastically restrained ends
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期刊论文
Cluster voltage control method for “Whole County” distributed photovoltaics based on improved differential
期刊论文
A combination of damage locating vector method (DLV) and differential evolution algorithm (DE) for structural
T. NGUYEN-THOI, A. TRAN-VIET, N. NGUYEN-MINH, T. VO-DUY, V. HO-HUU
期刊论文
Identification of faults through wavelet transform vis-à-vis fast Fourier transform of noisy vibration
null
期刊论文
Dynamics of structural systems with various frequency-dependent damping models
Li LI,Yujin HU,Weiming DENG,Lei LÜ,Zhe DING
期刊论文
A reversibility-gain model for integer Karhunen-Loève transform design in video coding
Xing-guo ZHU,Lu YU
期刊论文
Analytical and numerical investigation into the longitudinal vibration of uniform nanotubes
null
期刊论文
Analyzing the nonlinear vibrational wave differential equation for the simplified model of Tower Cranesby Algebraic Method
M.R. AKBARI,D.D. GANJI,A.R. AHMADI,Sayyid H. Hashemi KACHAPI
期刊论文
Analytical method of capsizing probability in the time domain for ships in the random beam seas
LIU Liqin, TANG Yougang, LI Hongxia
期刊论文
Tuned reactive power dispatch through modified differential evolution technique
S. BISWAS (RAHA), N. CHAKRABORTY
期刊论文
Review of MEMS differential scanning calorimetry for biomolecular study
Shifeng YU, Shuyu WANG, Ming LU, Lei ZUO
期刊论文