An Inverse Non-Linear Force Vibration Problem of Estimating the External Forces in a Damped System With Time-Dependent System Parameters

Huang, Cheng‐Hung

doi:10.1006/jsvi.2000.3196

Cited by 45 publications

(24 citation statements)

References 12 publications

(6 reference statements)

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“…However, in aspect of recognition accuracy, frequency response model function can cause an instable recognition and a decreased accuracy due to the matrix morbid. In terms of application scope, the frequency domain method is applicable to recognize stable loads [13,14]. Time domain method was a method that emerged only in the 1980s.…”

Section: Introductionmentioning

confidence: 99%

Qualitative Recognition of Typical Loads in Low‐Speed Rotor System

Zhang

Zhao-jian

2017

Mathematical Problems in Engineering

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While the load variations within the low speed rotor systems affect the operating conditions and mechanical properties, they may also provide information on machine faults. Therefore, load recognition is of great significance in operational monitoring for detecting early warning signs of failure and diagnosing faults. In this paper, five types of typical loads in a low-speed rotor system are qualitatively analyzed. Moreover, a method is presented based on the vibration signals from a low-speed rotor system using the ensemble empirical mode decomposition (EEMD), energy feature extraction, and backpropagation neural network (BPNN). A low-speed rotor test bench was designed and manufactured for load recognition and an experiment was set up based on certain load characteristics. Loading tests for five representative categories were conducted and various vibration signals were collected simultaneously. The EEMD was shown to eliminate the mode mixing seen in traditional EMD, which resulted in a clear decomposition of the signal. Finally, the characteristics were imported into a BPNN after energy feature extraction, and the different types of load were accurately recognized. Comparing the experimental results to existing data, a total recognition rate of 92.38% was achieved, demonstrating that the proposed method is both reliable and efficient.

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Section: Introductionmentioning

confidence: 99%

Qualitative Recognition of Typical Loads in Low‐Speed Rotor System

Zhang

Zhao-jian

2017

Mathematical Problems in Engineering

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“…On the other hand, inverse source/force problems for the wave equation have been less investigated. External force estimation consists of the inverse process of identifying the applied loadings from the output measurements of the system responses and can be experienced in many engineering applications dealing with wave, wind, seismic, explosion, or noise excitations, [2].…”

Section: Introductionmentioning

confidence: 99%

Determination of forcing functions in the wave equation. Part II: the time-dependent case

Hussein

Lesnic

2015

J Eng Math

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Abstract. The determination of an unknown time-dependent force function in the wave equation is investigated. This is a natural continuation of Part I (J. Eng. Maths 2015, this volume), where the space-dependent force identification has been considered. The additional data is given by a space integral average measurement of the displacement. This linear inverse problem has a unique solution, but it is still ill-posed since small errors in the input data cause large errors in the output solution. Consequently, when the input data is contaminated with noise we use the Tikhonov regularization method in order to obtain a stable solution. The choice of the regularization parameter is based on the L-curve method. Numerical results show that the solution is accurate for exact data and stable for noisy data.

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Section: Introductionmentioning

confidence: 99%

“…Recently, Huang [12] used the CGM to solve the inverse force vibration problems in estimating the external forces. In reference [12], the system parameters are assumed as functions of time, for this reason it can be classi"ed as a non-linear problem [13]. However, if we take a look at the problem from a purely mathematical viewpoint, it is not a genuine non-linear inverse vibration problem unless the system parameters are functions of the dependent variable, i.e., the displacement.…”

Section: Introductionmentioning

confidence: 99%

An Inverse Non-Linear Force Vibration Problem of Estimating the External Forces in a Damped System With Time-Dependent System Parameters

Cited by 45 publications

References 12 publications

Qualitative Recognition of Typical Loads in Low‐Speed Rotor System

Qualitative Recognition of Typical Loads in Low‐Speed Rotor System

Determination of forcing functions in the wave equation. Part II: the time-dependent case

A Non-Linear Inverse Vibration Problem of Estimating the External Forces for a System With Displacement-Dependent Parameters

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