Math 2.0

Mechanics of particles and systems Nonlinear mechanical dynamics Concept

Anharmonic oscillator

Builds on Harmonic oscillatorDuffing equationPendulum equation

Summary

An anharmonic oscillator is an oscillating system whose restoring force is not proportional to the displacement. It is what a real oscillator looks like once the displacement is no longer small, beyond the harmonic oscillator approximation. Its frequency depends on the amplitude, and under periodic forcing it shows nonlinear resonance and can behave chaotically. The pendulum equation and the Duffing equation are the standard examples.

Reading path

To understand this page from the ground up, read these 43 pages in order. The foundations come first.

  1. Complex numbers object
  2. Differential equation concept
  3. Function concept
  4. Hamiltonian system concept
  5. Homoclinic orbit concept
  6. Interval concept
  7. Melnikov method concept
  8. Euler's formula statement
  9. Ordinary differential equation definition
  10. Lipschitz condition definition
  11. Grönwall's inequality statement
  12. Order of a differential equation definition
  13. Solution of an ordinary differential equation definition
  14. Autonomous system definition
  15. Initial value problem definition
  16. Linear differential equation of order n definition
  17. Equilibrium point definition
  18. System of linear differential equations definition
  19. Uniqueness of solutions for Lipschitz vector fields statement
  20. Homogeneous linear equation definition
  21. Linear equation with constant coefficients definition
  22. Homogeneous linear system with constant coefficients definition
  23. Maximal solution definition
  24. Superposition principle statement
  25. Characteristic equation definition
  26. Matrix exponential as the solution of a linear system statement
  27. Flow of a vector field definition
  28. Solution space of a homogeneous linear equation has dimension n statement
  29. Lyapunov stability definition
  30. Trajectory definition
  31. Fundamental system of solutions definition
  32. Asymptotic stability definition
  33. First integral definition
  34. Solutions for distinct real roots statement
  35. Stability of linear systems via eigenvalues statement
  36. Solutions for repeated roots statement
  37. Linearisation at an equilibrium concept
  38. Solutions for complex conjugate roots statement
  39. Hyperbolic equilibrium point definition
  40. Harmonic oscillator example
  41. Pendulum equation example
  42. Duffing equation example
  43. Anharmonic oscillator concept

Further reading

  1. Web https://en.wikipedia.org/wiki/Anharmonicity
About this page
Tag4Z5EQ17Q60
URIm2://4Z5EQ17Q60
Kindconcept
WritingW0 stub
MSC70K25, 70K30, 34C15
UsesHarmonic oscillator, Duffing equation, Pendulum equation
Changed3 November 2026

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