Oscillator with third and fifth order terms?

  • Context: Graduate 
  • Thread starter Thread starter HomogenousCow
  • Start date Start date
  • Tags Tags
    Oscillator Terms
Click For Summary

Discussion Overview

The discussion centers around the modeling of oscillations using differential equations that include higher-order terms, specifically third and fifth order terms. Participants explore the implications of including these terms in the context of periodic motion and the characteristics of different systems.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes that typically only the first order term is considered for oscillations and inquires about literature on models that include third and fifth order terms.
  • Another participant provides a reference to a paper that may address the topic, although they suggest it might not be well-received.
  • A participant mentions the Duffing equation, indicating that the proposed equation could be a special case of it if limited to terms up to O(x^3).
  • It is suggested that including even-order terms could also allow for oscillation, but these terms may be negligible in systems with an odd response, where the transfer function is odd.
  • Some participants argue that many materials exhibit symmetry leading to an odd transfer function, while cautioning that this approximation may not hold true in electronic oscillators.

Areas of Agreement / Disagreement

Participants express differing views on the relevance and impact of including even-order terms in oscillation models, indicating that there is no consensus on the necessity or implications of these terms in various systems.

Contextual Notes

There are unresolved questions regarding the assumptions made about system responses and the applicability of the discussed models to different types of oscillators.

HomogenousCow
Messages
736
Reaction score
213
We usually only consider the first order term for an oscillation, are there any papers on extending that model and including third and fifth order terms (since only odd power terms would cause a periodic motion)?
The ODE would look like x''=-αx-βx^3+O(x^5)
 
Physics news on Phys.org
Look up the Duffing equation and its solution. Your equation would be a special case of that if only the terms up to O(x3) are considered.
 
Added even terms would let oscillate as well. They are negligible if your system has an odd response, that is, its transfer function is odd, and then the even components of the series expansion are zero.

Many materials behave symmetrically hence build an odd transfer function, but this approximation would be grossly false in an electronic oscillator for instance.
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 3 ·
Replies
3
Views
8K
  • · Replies 16 ·
Replies
16
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 15 ·
Replies
15
Views
4K
  • · Replies 21 ·
Replies
21
Views
20K
  • · Replies 11 ·
Replies
11
Views
5K