1. Anharmonic motion and non-harmonic motion means the same thing under oscillatory motion(non-harmonic motion may also mean non-oscillatory motion like linear motion etc..but keeping thing under the topic of oscillation here)

2. So, what we're going to study now is what's called small oscillations, or simple harmonic motion.

3. In addition the case of an arbitrary (not necessarily time harmonic) motion of the disk is considered.

4. To a first approximation, the motion in a normal vibration can be described as a kind of simple harmonic motion.

5. Anharmonic oscillation is defined as the deviation of a system from harmonic oscillation, or an oscillator not oscillating in simple harmonic motion.

6. Vibration test: The battery is rigidly clamped to the platform of a vibration machine and a simple harmonic motion having an amplitude of 0,8 mm (1,6 mm maximum total excursion) is applied.