## 6. Static and dynamic problems

### 6.1 Static problem

$\mathbf K \mathbf u = \mathbf f$

In this case there are no inertial or damping effects, or at least they are negligible. In the middle ear, for example, a static solution is applicable up to about 300 Hz.

At very low frequencies the ‘static’ solution may no longer work because of very slow time-varying effects such as thermal drift in electrical circuits, and creep or relaxation in biomechanical systems.

R. Funnell