#SMMS

(The progression from [[Structural dynamics (linear)]])

![[non-linear objects]]

## Example : non linear stiffness

The relation $F_0=Kx$ is no more, instead it becomes non linear :
$$F_0=K_1x+K_3x^3$$
It can be though of as the stiffness depends on the amplitude of the movement
![[non-linear stiffness]]
Frequency Response Function example for a stiffening object

![[non-linear FRF]]