A new method to extract modal parameters using output-only responses

Kim, Byeong Hwa; Stubbs, Norris; Park, Taehyo

doi:10.1016/j.jsv.2004.02.026

Cited by 113 publications

(63 citation statements)

References 6 publications

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“…To the known input and output signals, the mass matrix, damping matrix, and stiffness matrix can be solved using formula (6). 25,28 Modal test of truck cab…”

Section: Theory Of Modal Analysismentioning

confidence: 99%

“…And EMA can be combined with the computer-aided engineering (CAE) that provides theoretical simulation to verify the structural theoretical model, and hence, the virtual testing can be implemented to assist product design and development. [5][6][7] In the late 1960s, Cole and Henry 8 proposed a random decrement technique (RDT) based on the single-point excitation and single-order modal testing and applied it to the modal parameter identification of space shuttle. The random decrement method is a single-channel signal, which cannot be directly used for modal parameter identification.…”

Section: Introductionmentioning

confidence: 99%

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Modal analysis of a truck cab using the least squares complex exponent test method

Fan

Wang

Zhao

2015

Advances in Mechanical Engineering

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This article introduces the basic theory of modal analysis. The modal testing system is established for a developing truck body. Using a pseudo-random excitation signal along the x, y, and z directions, the modal test is carried out to obtain the dynamic performance by multi-point excitations. The transfer function set is obtained by averaging all transfer functions, and the set is processed by order selection to get 28 order modes. Fitting modal parameters and normalizing modal mass can gain natural frequencies and vibration modes of cab. Then, the modal analysis of truck cab is calculated based on the finite element method, and the results are compared with the test results. The improved measures are put forward to enhance the local stiffness, avoid modal coupling, and reduce vibration noise. So, this article supplies a reference for the dynamic test for the large body.

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“…To the known input and output signals, the mass matrix, damping matrix, and stiffness matrix can be solved using formula (6). 25,28 Modal test of truck cab…”

Section: Theory Of Modal Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modal analysis of a truck cab using the least squares complex exponent test method

Fan

Wang

Zhao

2015

Advances in Mechanical Engineering

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“…Modal identification techniques can be classified into two categories: input-output techniques and output-only techniques. While in input-output techniques the excitation is measured and frequency response functions (FRF) can be therefore derived, output-only techniques are only based on the dynamic response, remaining the excitation source as unknown (2). For civil engineering structures, where external sophisticated equipment would be needed to excite a wide band of frequencies and simultaneously measure the input signal, output-only techniques have shown to be very appropriate to extract dynamic properties.…”

Section: Introductionmentioning

confidence: 99%

Damage identification of RC bridge decks under fatigue loading

Zanuy¹,

Maya-Duque²,

Gallego³

et al. 2014

Inf. constr.

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The complex nature of structural phenomena still requires the comparison between numerical models and the real structural performance. Accordingly, many civil structures are monitored to detect structural damage and provide updated data for numerical models. Monitoring usually relies on the change of dynamic properties (experimental modal analysis). Regarding concrete structures, existing works have typically focused on the progressive decrease of natural frequencies under gradually increasing loads. In this paper, high-cycle fatigue effects are analyzed. An experimental campaign on specimens reproducing the top slab of concrete girders has been carried out, including fatigue tests and a reference static test. Impact-excitation tests were done at different stages to extract dynamic properties. Output-only models (only based on the structural response to an external excitation that is not measured) were used as identification techniques. The evolution of dynamic properties was correlated with damage development, with emphasis on the fatigue process stages: crack formation, cyclic reduction of tension-stiffening and brittle fracture of the reinforcement.Keywords: Concrete bridges; fatigue; cracking; damage identification; output-only models. RESUMEN La naturaleza compleja de muchos fenómenos estructurales requiere que los modelos numéricos necesiten ser verificados con el comportamiento estructural real. Por ello, muchas estructuras son monitorizadas, tanto para detectar posibles daños estructurales como para proporcionar datos a incluir en los modelos. A menudo

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“…Incremental dynamic analysis and modal pushover analysis approaches were implemented to predict nonlinear seismic response of the building using the calibrated model. Kim et al [8] proposed a time domain method for identifying dynamic characteristics of a single degree of freedom system with unknown excitations. They verified the effectiveness of the method through numerically simulated data and data collected from the experiment carried out on a reinforced concrete highway bridge located in Southern California.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Characteristic Identification of Seismic-Excited Multi-Story Buildings through Response-Only Technique

Budipriyanto¹,

Suprobo²

2014

MST

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Identifying dynamic characteristics of civil engineering structures is still a challenging task. It intends to assess behavior of the structures under time-dependent loads. This paper discusses a methodology suitable for identifying the characteristics of multi-story buildings using only their measured response under earthquake ground excitations. Appropriateness of technique used for structural identification was corroborated through coherence of the structure's responses. The methodology was applied for identifying the characteristics of 14-story and 20-story office buildings located in a high seismic region. Responses of these two buildings recorded during three different seismic ground motions were investigated. The buildings' response spectral densities and singular values were computed and utilized to identify their dynamic characteristics, viz. modal frequencies, damping factors, and mode types such as bending or torsion mode. Results of this study were validated through comparisons with the results reported using different structural identification techniques. It indicated that the methodology implemented in this study was capable of identifying the dynamic characteristics of multi-story buildings using responses under seismic ground motions. Abstrak Identifikasi Karakteristik Dinamik Gedung Bertingkat dengan Menggunakan Respons Seismik dari Struktur.Identifikasi karakteristik dinamik struktur sipil bertujuan untuk mempelajari perilakunya akibat beban yang bervariasi dengan waktu. Makalah ini membahas metodologi untuk identifikasi struktur gedung bertingkat dengan hanya menggunakan respons yang diukur selama terjadi gempa. Dalam makalah ini, koherensi respons struktur digunakan untuk menjustifikasi penerapan metode yang dipakai. Metodologi tersebut diaplikasikan untuk identifikasi karakteristik dinamik (frekwensi, faktor redaman, dan ragam) struktur gedung bertingkat 14 dan 20 dengan menggunakan respons percepatan yang direkam selama tiga kejadian gempa. Hasil dari studi ini dibandingkan dengan hasil studi terdahulu yang diperoleh dengan metode yang berbeda. Hasil tersebut mengindikasikan bahwa metodologi ini mampu mengidentifikasi karakteristik dinamik struktur gedung bertingkat dengan menggunakan responsnya akibat beban gempa.

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A new method to extract modal parameters using output-only responses

Cited by 113 publications

References 6 publications

Modal analysis of a truck cab using the least squares complex exponent test method

Modal analysis of a truck cab using the least squares complex exponent test method

Damage identification of RC bridge decks under fatigue loading

Dynamic Characteristic Identification of Seismic-Excited Multi-Story Buildings through Response-Only Technique

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