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Mechanical resonance is the tendency of a mechanical system to respond at greater amplitude when the frequency of its oscillations matches the system's natural frequency of vibration (its resonance frequency or resonant frequency) closer than it does other frequencies. It may cause violent swaying motions and potentially catastrophic failure in ...
The most common method for detecting the mechanical resonant spectrum is illustrated in Fig. 2, where a small parallelepiped-shaped sample is lightly held between two piezoelectric transducers. One transducer is used to generate an elastic wave of constant amplitude and varying frequency, whereas the other is used to detect the sample's resonance.
[1] [non-primary source needed] In some degree it is an analog of coupling coefficient of coupled inductors. Meaning of this term has been improved many times with progress in theory of coupled resonators and filters. Later definitions of the coupling coefficient are generalizations or refinements of preceding definitions.
The vibrations of the membrane are given by the solutions of the two-dimensional wave equation with Dirichlet boundary conditions which represent the constraint of the frame. It can be shown that any arbitrarily complex vibration of the membrane can be decomposed into a possibly infinite series of the membrane's normal modes.
Different resonant frequencies can be excited dependent on the position of the support wires, the mechanical impulse and the microphone. The two most important resonant frequencies are the flexural which is controlled by the Young's modulus of the sample and the torsional which is controlled by the shear modulus for isotropic materials.
Schematic of energy levels involved in two photons absorption. In atomic physics, two-photon absorption (TPA or 2PA), also called two-photon excitation or non-linear absorption, is the simultaneous absorption of two photons of identical or different frequencies in order to excite an atom or a molecule from one state (usually the ground state), via a virtual energy level, to a higher energy ...
Two conditions must be satisfied for the occurrence of Fermi resonance: The two vibrational modes of a molecule transform according to the same irreducible representation in their molecular point group. In other words, the two vibrations must have the same symmetries (Mulliken symbols). The transitions coincidentally have very similar energies.
The whirling frequency of a symmetric cross section of a given length between two points is given by: N = 94.251 E I m L 3 RPM {\displaystyle N=94.251{\sqrt {EI \over mL^{3}}}\ {\text{RPM}}} where: E = Young's modulus, I = second moment of area , m = mass of the shaft, L = length of the shaft between points.