Moyne and Tebec  used the FEM/BEM approach to calculate noise radiated from a gearbox and claimed that ribs not only reduce sound power and modify the eigenfrequencies
by stiffening the structure, but also they form an obstacle to the radiating sound field where sound wave reflections are important.
7 there must exist a set of certain frequencies [[omega].sub.mn] (the eigenfrequencies
) associated with the horizontal wavelengths [k.sub.m] determined by solving eq.
The first five eigenfrequencies
are calculated and presented in Table 2.
(i) Finite element methods (FEMs) are used in order to calculate the different eigenfrequencies
of the tooth, considered as an elastic solid [21, 22].
The simulation was performed to calculate the eigenfrequencies
for the first six modes.
and modal analysis of uniaxial, biaxial, and gyroelectric spherical cavities," IEEE Transactions on Microwave Theory and Techniques, vol.
These ones are based on the idea that a damage causes a reduction of the local physical stiffness, causing the modification of modal parameters (eigenfrequencies
, damping ratios, and eigenvectors).
The third term in the expression of (23) is the usual quantum corrections to the energy due to the oscillation of the particle inside the drop with eigenfrequencies
determined by the form of the distribution function of the particles in the drop.
Du, "Is the Burton-Miller formulation really free of fictitious eigenfrequencies
?," Engineering Analysis with Boundary Elements, vol.
(32) Since then, the eigenfrequencies
of these oscillations and their decay rates have been measured and compiled after large earthquakes.
A set of eigenfrequencies
[[omega].sub.i] and the corresponding eigenvectors (mode shapes) [[omega].sub.i] are first obtained.
The soundboard was modelled as a rectangular plate in 3D with a thickness of 3 mm and COMSOL Multiphysics was used to obtain eigenvectors (mode shapes) corresponding to eigenfrequencies
up to 100 Hz.