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The mode shapes of a tennis racket and the effects of vibration dampers on those mode shapes
The Journal of the Acoustical Society of America, 2009The vibrational behavior of a tennis racket was studied using a speckle-pattern interferometry system. Specifically, the first 12 mode shapes of a racket are shown and discussed. In addition, the speckle-pattern interferometry system was used to compare the effects of four commercially available vibration damping systems.
Nicholas, Timme, Andrew, Morrison
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Detection of Soliton Shape Modes in Polyacetylene
Physical Review Letters, 1986We observed soliton shape modes by photoinduced absorption in partially isomerized ${(\mathrm{CH})}_{x}$ and ${(\mathrm{CD})}_{x}$, coexisting with the soliton translational modes. The shape modes' ir activity, their dependence on the degree of isomerization, and the photoinduced spectra are explained in detail by a symmetry-breaking interaction which ...
, Vardeny +6 more
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Acoustic cavity modes in lens-shaped structures
The Journal of the Acoustical Society of America, 2003A method for solving exactly the Helmholtz equation in parabolic rotational coordinates is presented using separability of the eigenfunctions and the Frobenius power series expansion technique. Two examples of interest in acoustics are considered and analyzed quasianalytically: The acoustic pressure in a cavity defined by two paraboloids (forming a ...
Willatzen, Morten, Lew Yan Voon, L.C.
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A neural mode shape identifier
Proceedings of 3rd International Symposium on Uncertainty Modeling and Analysis and Annual Conference of the North American Fuzzy Information Processing Society, 2002A first stage for a fuzzy neural active controller is developed. Neural network technology is utilized in the real time identification of the mode of vibration of any structural system under seismic loading. The parallel processing nature of neural networks fit the nature of multi degree of freedom systems.
M.H.M. Hassan, B.M. Ayyub
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Computers & Structures, 1989
Abstract Given an arbitrary modal matrix describing the vibrational displacements of a discrete, linear, undamped shear building, a theoretical solution is presented to find the mass and stiffness coefficients of the system; thereby reversing the usual vibration problem.
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Abstract Given an arbitrary modal matrix describing the vibrational displacements of a discrete, linear, undamped shear building, a theoretical solution is presented to find the mass and stiffness coefficients of the system; thereby reversing the usual vibration problem.
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ON THE MODE SHAPES OF THE HELMHOLTZ EQUATION
Journal of Sound and Vibration, 1995Abstract The differential equation governing the free, transverse vibration of a thin membrane, the Helmholtz equation, is also the governing equation for problems of microwave propagation, stress waves and acoustics. Simple analytical solutions may be found in elliptic and parabolic co-ordinates.
G.M.L. Gladwell, N.B. Willms
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Mode shape identification and orthogonalization
AIAA Journal, 1988An identification procedure to improve the mass-weighted orthogonality of measured mode shapes is introduced. The procedure takes into account the degree of mode isolation present during measurement. This is accomplished by establishing a set of new mode shapes, from the measured vectors, that satisfy cross-orthogonality constraints and are a minimum ...
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Frequency-shaped sliding modes: analysis and experiments
IEEE Transactions on Control Systems Technology, 1997A recent improvement over a motion control algorithm, sliding mode control with perturbation estimation, is considered in this paper. It enforces the nonlinear system to follow a desired trajectory despite the presence of modeling uncertainties and disturbances.
Jairo Terra Moura +2 more
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SENSITIVITY-BASED OPERATIONAL MODE SHAPE NORMALISATION
Mechanical Systems and Signal Processing, 2002In the past few years, in-operation modal analysis has become a valid alternative for structures where classic forced vibration tests would be difficult, if not impossible, to conduct. A disadvantage of this method is that the excitation forces are unknown. Therefore, not all modal parameters can still be estimated.
Parloo, Eli +3 more
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Surface vibrational modes in disk-shaped resonators
Ultrasonics, 2014The natural frequencies and distributions of displacement components for the surface vibrational modes in thin isotropic elastic disks are calculated. In particular, the research is focused on even solutions for low-lying resonant vibrations with large angular wave numbers.
A V, Dmitriev +2 more
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