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Modal testing

About: Modal testing is a research topic. Over the lifetime, 4047 publications have been published within this topic receiving 64772 citations.


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TL;DR: In this article, a finite element model of the human hand-arm system is presented to derive natural frequencies and mode shapes, which is calibrated by considering modal parameters obtained from experimental vibration analyzed by using operational modal analysis (OMA) and transmissibility.
Abstract: This study presents a finite element (FE) model of the human hand-arm system to derive natural frequencies and mode shapes. The FE model is calibrated by considering modal parameters obtained from experimental vibration analyzed by using operational modal analysis (OMA) and transmissibility. Modal and harmonic analyses of the FE model are performed for two boundary conditions. The first one considers fixed shoulder condition while the second one introduces the trunk in order to permit motion of the shoulder. The results show that the natural frequencies of the second model that permits shoulder motion are comparable with those determined from measurements. Especially, the natural frequency about 12 Hz, which is corresponding to the frequency of maximum weight in ISO-5349-1 (2001), is not present in the model with fixed shoulder condition, while it appears in the second model. The results of the present study suggest that improved finite element models of the human hand-arm system may reveal hand-arm injury mechanism, the understanding of which may assist in deriving appropriate frequency weightings for the assessment of different components of the hand-arm vibration syndrome.

23 citations

Journal ArticleDOI
TL;DR: In this paper, the authors generalized the simple modal damping identification model of Hart and Vasudevan to the frequency domain and provided time-invariant damping ratios of building structures under seismic excitations in terms of modal participation factors and the roof-tobasement transfer function.
Abstract: The simple modal damping identification model of Hart and Vasudevan is generalized. The model works in the frequency domain and provides time-invariant modal damping ratios of building structures under seismic excitations in terms of modal participation factors and the roof-to-basement transfer function. Translational as well as torsional modes of vibration are considered. The performance of the model is assessed through a small, yet indicative, number of numerical examples involving steel plane and space frames under seismic excitations and on the basis of a number of criteria an ideal identification model should satisfy. It is concluded that the presented model, in spite of its simplicity, gives very good results for low-amplitude seismic excitations resulting in linear elastic structural behavior (with damping) even for cases of closely spaced modes, local modes, and very small or large amounts of damping. Some numerical pitfalls regarding the application of the model are mentioned and carefully treated. The limitations of the model when used in conjunction with inelastic structural behavior are determined and discussed. Experimental verification of the model is also provided.

23 citations

Journal ArticleDOI
TL;DR: In this paper, a method to utilise modal control using the decoupled second-order matrix equations involving non-classical damping is proposed, in which the system damping matrix contains skew-symmetric components.

23 citations

Journal ArticleDOI
TL;DR: In this article, the authors measured the natural frequencies of rotating disk platters with the help of capacitance type of probe and found that the major noise source in the lower speed hard disk drive was the actuator arm fly over the platter whereas in the case of higher speed drives, the main source was the disk platter air flutter noise.

23 citations

Journal ArticleDOI
TL;DR: In this article, the authors used a non-contacting laser vibrometer measurement system for the dynamic modal testing of extremely lightweight inflatable structures, and found that the results may vary dramatically according to the presence of either thermal vacuum or ambient atmospheric conditions.
Abstract: In the dynamic modal testing of extremely lightweight inflatable structures, the results may vary dramatically according to the presence of either thermal vacuum or ambient atmospheric conditions. Unique aspects of modal testing techniques for an inflatable solar concentrator are identified, including the use of a noncontacting laser vibrometer measurement system. For the thermal vacuum environment, mode shapes and frequency response functions are compared for three different test article inflation pressures at room temperature. Modes that persist through all inflation pressure regimes are identified, as are modes that are unique for each pressure. In atmospheric pressure and room temperature conditions, dynamic measurements were obtained for the expected operational inflation pressure. Experimental mode shapes and frequency response functions for ambient conditions are described and compared to the results from the thermal vacuum tests. There is a surprising lack of correlation in test results between the two test conditions, which may be explained by damping and air mass considerations. Results of this investigation point out the necessity of testing inflatable space structures in vacuum conditions before they can be launched.

23 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202367
2022164
202141
202059
201967
201878