There is already a post about ground vibration tests (GVT).

In these tests they normally use accelerometers, so I think this is a good thing to blog about.

There are 2 types of accelerometers, first you have the AC – and secondly the DC – coupled devices. The AC – coupled device can’t measure static acceleration, so it doesn’t register the gravity. While a DC device can measure starting from zero Hertz.

An AC device isn’t suited to follow slow motions, because of the limitations by its RC time constant which defines its high-pass characteristics. The DC on the other hand has no problem tracking a slow motion.

A typical AC sensor is a piezoelectric accelerometer. While a typical DC-accelerometer is the capacitive (used in air-bags and mobile devices) or a piezoresistive one.

I have found a good paper about this, it gives a lot of info and a good comparison.

In GVT they use AC and DC sensors, also force and temperature sensors. The fact they also use temperature sensors is because DC piezoresistive sensors are very temperature dependent.

 

But of course the technology isn’t standing still so there is a new kind of sensor they are testing for the GVT. So stay tuned for my next post if you want to know more about it.

 

See you next time followers.

Advertisements