Calculation of different natural frequencies of a material

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Discussion Overview

The discussion revolves around the concept of natural frequencies associated with materials and oscillators, exploring the calculation of these frequencies in various systems, including one-dimensional oscillators and more complex structures. The scope includes theoretical considerations and examples from physics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that a simple one-dimensional oscillator has a single natural frequency calculated using the formula 1/2π√(k/m), while others argue that more complex systems can exhibit multiple natural frequencies.
  • One participant asserts that for the simple harmonic oscillator, only one frequency satisfies the equation mω²=k, indicating that m and k being constants lead to a unique ω.
  • Another participant introduces the concept of standing waves in stretched strings, suggesting that these systems can vibrate at multiple frequencies obtained by solving specific equations.
  • There is mention of atomic states where energy levels are quantized, leading to discrete energy interactions analogous to harmonic oscillators, with energy amounts being integer multiples of a fundamental energy unit.
  • One participant clarifies that while the simple harmonic oscillator has one proper frequency, more complicated systems have multiple proper frequencies, referred to as normal modes, which may or may not be integer multiples of a fundamental frequency.
  • Another participant notes that integer multiples of the natural resonance frequency can create resonance, albeit to a lesser degree, referring to these as harmonics or overtones.

Areas of Agreement / Disagreement

Participants express differing views on the number of natural frequencies in oscillators, with some asserting a single frequency for simple systems and others acknowledging multiple frequencies in more complex systems. The discussion remains unresolved regarding the exact nature of these frequencies across different contexts.

Contextual Notes

Participants reference various systems and conditions under which natural frequencies are determined, highlighting the dependence on system complexity and boundary conditions. There are unresolved aspects regarding the relationship between fundamental frequencies and their multiples in different contexts.

Akshay Gundeti
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Hi,
As far as I know, every material has different sets of natural frequencies associated with it.

For example,
A simple one dimensional oscillator with stiffness "k" and mass "m" has a formula for calculating its natural frequency = 1/2pie*squareroot(k/m). I was wondering if there are different natural frequencies associated with this oscillator then how will we calculate the other frequencies.

Is is just the integer multiple of the above frequency?

Thanks,
 
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According to me this system has only One natural frequency. Because there is no other value of the frequency that satisfies the equation mω^2=k, since m and k are constants and hence only one ω is possible or one frequency possible.

EDIT: well, there are systems which can vibrate with more that one frequency. For example the standing waves produced in a stretched string. Well, these are obtained by solving equations, the possible frequency it can vibrate. Here by equation,only one frequency is possible.
 
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On atomic states, oscillators energy hasn't continues values. Thus, energy interactions limited to these (quantum) amounts of energy.
Because most of local potentials inside atoms likes to harmonic oscillator potential, these energy amounts are like integer products of a basic amount ##\hbar\omega##. This is analogue to the static wave conditions for sound waves.
 
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Akshay Gundeti said:
Hi,
As far as I know, every material has different sets of natural frequencies associated with it.

For example,
A simple one dimensional oscillator with stiffness "k" and mass "m" has a formula for calculating its natural frequency = 1/2pie*squareroot(k/m). I was wondering if there are different natural frequencies associated with this oscillator then how will we calculate the other frequencies.

Is is just the integer multiple of the above frequency?

Thanks,
As was mentioned already, the simple harmonic oscillator has only one proper (or "natural") frequency.
More complicated systems have more than one proper frequency. They are also called normal modes frequencies. There are formulas for simple geometric shapes and appropriate boundary conditions. The frequencies may or my not be multiples of a fundamental frequency.
For example, a cord fixed at the ends has frequencies that are multiples of the fundamental. A membrane (like a drum) fixed around the edge does not. The ratios between frequencies are not integer numbers.
 
Thank you all very much for the explanations. Doubt cleared! :)

I really appreciate them.

Thanks,
 
It's probably worth pointing out that usually integer multiples of the natural resonance frequency create resonance too, just to a lesser degree. Those are the harmonics of that frequency (in music called overtones).
 

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