Overview of modal analysis

He, Jianwei; Zhang, Fu

doi:10.1016/b978-075065079-3/50001-2

Cited by 93 publications

(134 citation statements)

References 2 publications

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“…The notation R is here used as a general response matrix, for any class of quantities. Each element of the this matrix hereby represents the response, which can be displacement, the velocity or the acceleration or their inverses, of the structure in the i th degree of freedom due to a harmonic input of a certain excitation frequency in the j th degree of freedom [23]. It will below be specialized to express the displacement response values in the dynamic flexibility matrix, which is commonly the most easily measured quantity.…”

Section: Pre-measurement Analysismentioning

confidence: 99%

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Vibration health monitoring for tensegrity structures

Ashwear

Eriksson

2017

Mechanical Systems and Signal Processing

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Tensegrities are assembly structures, getting their equilibrium from the integrity between tension in cables and compression in bars. During their service life, slacking in their cables and nearness to buckling in their bars need to be monitored to avoid a sudden collapse. This paper discusses how to design the tensegrities to make them feasible for vibrational health monitoring methods. Four topics are discussed; suitable finite elements formulation, pre-measurements analysis to find the locations of excitation and sensors for the interesting modes, the effects from some environmental conditions, and the pre-understanding of the effects from different slacking scenarios.

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Section: Pre-measurement Analysismentioning

confidence: 99%

“…This is seen as a description of measurable displacements as functions of an induced excitation, where the rows of the matrix H are corresponding to the sensor locations, and its column are related to the excitation locations [23].…”

Section: The Frequency Response Functions Frfmentioning

confidence: 99%

Vibration health monitoring for tensegrity structures

Ashwear

Eriksson

2017

Mechanical Systems and Signal Processing

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“…43 In equation (11), N represents the maximum order of the system nonlinearity and h ði, j Þ ð 1 , . .…”

Section: Fs Lðiþmentioning

confidence: 99%

“…Equation (5) is the basis of the modal analysis method, which is a strong technique for indicating dynamical properties of engineering structures. 43 In the linear system, the displacements x i ðtÞði ¼ 1, 2, . .…”

Section: Optimal Sensor Placementmentioning

confidence: 99%

Optimal placement of sensors and piezoelectric friction dampers in the pipeline networks based on nonlinear dynamic analysis

Shokouhi

Yuan

Zhu

2017

Journal of Low Frequency Noise, Vibration and Active Control

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Experiences of past earthquakes demonstrate that pipeline systems have no proper performance when exposed to severe earthquakes. In this study, sensor and damper placement approaches are presented for doing reliable health monitoring and seismic retrofitting of the piping networks. Since most of the available sensor placement methods are based on modal analysis results, the authors propose a new scheme that relies on the nonlinearity which utilizes nonlinear time history analysis results, and genetic algorithm is selected to act as the methodology of optimization as well. The results demonstrate that the proposed optimal sensor configuration strategy is more accurate and efficient than the extended modal assurance criterion method. To assess the number of sensors, a sensitivity analysis is undertaken in which the number of sensors computed optimally by the proposed algorithm contains the least convergence error. In addition, the number of iterations and the time consumed in the proposed approach are considerably less than the extended modal assurance criterion method. Moreover, the efficiency of the proposed sensor placement scheme was compared with a new algorithm proposed by Sun and Büyükö ztürk, named discrete artificial bee colony, where the simulation result demonstrates high accuracy of the proposed sensor configuration approach. The initial time history analysis results show the vulnerable points of the system, which destroyed due to the applied seismic waves. Hence, to enhance the seismic performance of the system, piezoelectric friction dampers are optimally placed, where it can be clearly seen that the optimal arrangement of piezoelectric friction dampers in the piping system can significantly decrease the seismic response.

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“…The dynamic properties of the structure were estimated from the sum frequency response function of every test by the so called peak-picking method. Peak picking is a frequency domainbased technique and a discussion of method is available in reference [12] …”

Section: Structure Description and Experimental Proceduresmentioning

confidence: 99%

Finite Element Model Updating of a Thin Wall Enclosure under Impact Excitation

David-West¹,

Wang²,

Cooper

2010

AMM

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Simulation result of a structural dynamics problem is dependent on the techniques used in the finite element model and the major task in model updating is determination of the changes to be made to the numerical model so that dynamic properties are comparable to the experimental result. In this paper, the dynamic analysis of a thin wall structure ( approx. 1.5±0.1 mm thick) was realized using the Lanczos tool to extract the modes between 0 and 200 Hz, but the interest was to achieve a good aggreement between the first ten natural frequencies. A shell element with mid size nodes was used to improve the finite element result and the model was tunned using the damping constant, material properties and discretization. The correlation of the results from the impact excitation response test and the finite element was significantly improved. A correlation coefficient of 0.99 was achieved after tunning the model.

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Overview of modal analysis

Cited by 93 publications

References 2 publications

Vibration health monitoring for tensegrity structures

Vibration health monitoring for tensegrity structures

Optimal placement of sensors and piezoelectric friction dampers in the pipeline networks based on nonlinear dynamic analysis

Finite Element Model Updating of a Thin Wall Enclosure under Impact Excitation

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