nnImproved thermoacoustic sound projectors by vibration mode modification

The paper examines effectiveness of the vibration correlation technique which allows determining the buckling or limit loads by means of measured natural frequencies of structures. A steel silo segment with a corrugated wall, stiffened with cold-formed channel section columns was analysed. The investigations included numerical analyses of: linear buckling, dynamic eigenvalue and geometrically static non-linear problems. Both perfect and imperfect geometries were considered. Initial geometrical imperfections included first and second buckling and vibration mode shapes with three amplitudes. The vibration correlation technique proved to be useful in estimating limit or buckling loads. It was very efficient in the case of small and medium imperfection magnitudes. The significant deviations between the predicted and calculated buckling and limit loads occurred when large imperfections were considered.

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A New Vibration Mode in Tall, Narrow Piezoelectric Elements

10.1109/ultsym.1979.197173 ◽

1979 ◽

Cited By ~ 7

Author(s):

J.D. Larson

Keyword(s):

Vibration Mode ◽

Piezoelectric Elements

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Splitting of vibration mode in an imperfect submicron circular plate

Acta Mechanica ◽

10.1007/s00707-020-02932-z ◽

2021 ◽

Author(s):

Jicheng Zhang ◽

Lifeng Wang ◽

Guoan Tai ◽

Jianxin Zhou ◽

Wei Sun ◽

...

Keyword(s):

Circular Plate ◽

Vibration Mode

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Strain Shift Coefficients for Phonons in Si-Ge Heterostructures

MRS Proceedings ◽

10.1557/proc-239-449 ◽

1991 ◽

Vol 239 ◽

Cited By ~ 4

Author(s):

J.-M. Baribeau ◽

D. J. Lockwood

Keyword(s):

Molecular Beam ◽

Composition Dependence ◽

Vibration Mode ◽

Phonon Frequency ◽

Longitudinal Optical ◽

Stress Factor ◽

Double Crystal ◽

Raman Scattering Spectroscopy ◽

X Ray ◽

Shift Coefficient

ABSTRACTStrain shift coefficient measurements for longitudinal optical phonons in molecular beam epitaxy grown metastable pseudomorphic Si1−xGex layers on (100) Si (0 < x < 0.35) and Ge (0.80 < x < 1) are reported. Strain in partially relaxed annealed specimens was obtained by double-crystal x-ray diffractometry and the corresponding strain phonon shift was measured by Raman scattering spectroscopy. For epilayers grown on Si it was found that the epilayer Si-Si phonon frequency varies linearly with strain. The magnitude of the strain shift coefficient b however showed a small composition dependence varying from b ≈ -700 cm-1 at x = 0 to b ≈ -950 cm-1 at x = 0.35, corresponding to a stress factor τ = 0.40 + 0.57x: + 0.13x2 cm-1/kbar. For the Ge-Ge vibration mode in epilayers grown on Ge, b decreased from ∼-425 cm-1 at x = 1 to ∼-500 cm-1 at x = 0.8, corresponding to a stress factor τ ≈ 0.52 – 0.14x - 0.08x2 cm-1/kbar.

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Identifying VIV Vibration Modes by Use of the Empirical Orthogonal Functions Technique

21st International Conference on Offshore Mechanics and Arctic Engineering, Volume 1 ◽

10.1115/omae2002-28425 ◽

2002 ◽

Cited By ~ 3

Author(s):

Gudmund Kleiven

Keyword(s):

Model Test ◽

Vibration Mode ◽

Multivariate Data ◽

Empirical Orthogonal Functions ◽

Mode Shapes ◽

Data Sets ◽

Vibration Modes ◽

Ocean Engineering ◽

Orthogonal Functions ◽

Related Technique

The Empirical Orthogonal Functions (EOF) technique has widely being used by oceanographers and meteorologists, while the Singular Value Decomposition (SVD being a related technique is frequently used in the statistics community. Another related technique called Principal Component Analysis (PCA) is observed being used for instance in pattern recognition. The predominant applications of these techniques are data compression of multivariate data sets which also facilitates subsequent statistical analysis of such data sets. Within Ocean Engineering the EOF technique is not yet widely in use, although there are several areas where multivariate data sets occur and where the EOF technique could represent a supplementary analysis technique. Examples are oceanographic data, in particular current data. Furthermore data sets of model- or full-scale data of loads and responses of slender bodies, such as pipelines and risers are relevant examples. One attractive property of the EOF technique is that it does not require any a priori information on the physical system by which the data is generated. In the present paper a description of the EOF technique is given. Thereafter an example on use of the EOF technique is presented. The example is analysis of response data from a model test of a pipeline in a long free span exposed to current. The model test program was carried out in order to identify the occurrence of multi-mode vibrations and vibration mode amplitudes. In the present example the EOF technique demonstrates the capability of identifying predominant vibration modes of inline as well as cross-flow vibrations. Vibration mode shapes together with mode amplitudes and frequencies are also estimated. Although the present example is not sufficient for concluding on the applicability of the EOF technique on a general basis, the results of the present example demonstrate some of the potential of the technique.

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Surface coating influence on elastic properties of spruce wood by means of holographic vibration mode visualization

10.1117/12.353047 ◽

1999 ◽

Cited By ~ 1

Author(s):

M. Bongova ◽

Stanislav Urgela

Keyword(s):

Elastic Properties ◽

Surface Coating ◽

Vibration Mode ◽

Spruce Wood

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Online Monitoring ICE Powers Based on the Crankshaft Angular Vibration

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.48-49.773 ◽

2011 ◽

Vol 48-49 ◽

pp. 773-778 ◽

Cited By ~ 1

Author(s):

Chun Rong Hua ◽

Da Wei Dong ◽

Bing Yan ◽

Ming Heng Xu

Keyword(s):

Reference Point ◽

Online Monitoring ◽

Vibration Mode ◽

Vibration Displacement ◽

Rotating Speed ◽

Rigid Body Model ◽

Angular Vibration ◽

Cubic Polynomial ◽

Experimental Researches ◽

Online Monitor

A new method of online monitoring ICE powers based on the crankshaft angular vibration is proposed. It has deduced that when each cylinder works uniformly at a certain rotating speed, and the vth order angular vibration mode of crankshaft nears plane vibration mode such as “quasi-rigid body model” or “quasi-trapeziform model”, so a cubic polynomial can represent the relationship between the vth order angular vibration displacement amplitude of the crankshaft reference point and the engine powers, thereby the angular vibration of reference point could be used to online monitor engine powers. Through the simulation and experimental researches on a 6240 and a 4100 diesel engine, it shows that the engine powers fitted with the angular vibration displacement amplitudes of reference point are close to the measured or theoretical powers comparatively, and the maximum errors is only 2.95%, which verifies the feasibility and practicability of the method consequently.

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