Acoustic Emission Sensors

[nickagian]

Hi to all!

I am supposed to design an electronics system that uses Acoustic Emission (AE) transducers to detect cracks and damages in materials. In essence, I need two paths : transmit (TX) and receive (RX).

-> For the TX path, the transducers act as actuators. They must be activated with a sine wave pulse and they emit acoustic signals in the material.

-> For the RX path, the transducers act as sensors. They receive acoustic signals from the material, either passively created by the damage or actively by the actuators.

The problem is that I have never designed something like that and I would like some help, from anyone that knows, mainly for the RX path. Does anyone know what analogue front-end is required for the AE sensors, between the devices and the A/D converter? Some amplification stage maybe? For the TX path, I intend to use a microcontroller in order to create the required pulses.

I would appreciate any help.

Nick

 

[canadaelk]

You would like to build an accoustical reflectometer. How deep/wide are these cracks? Try the Bruel & Kjer (bkhome.com) library section for some ideas.
If these cracks are irregular how do you intend to identify (read) the reflection?
Interesting though!

 

[Ubergeek63]

I have two words for you: OVER and KILL

you do not need a nice sine wave or multiple sensors, but you do need fast hardware

I do it with a HV pulse into a piezo transducer to measure material length by length of time to the echo ... if you are going down a length of material you would know if it were cracked by the sudden length change

https://www.bidwellinc.com/www/powerdyne/boltgages.html they are currently selling my version of it: the BG4

dan

 

[Vizier87]

they are currently selling my version of it: the BG4

wow.. you designed it?

 

[Ubergeek63]

wow.. you designed it?

for practical purposes. I was told to redesign it using as much of that one as i could... electrically there was nothing worth saving so I started from scratch. Outside the BG4 is similar but inside the only thing it has in common with the BG3 is the display module's form factor (it is a transflective black on white with a white LED backlight instead of a transparent with a yellow LED backlight)

the end result was a machine that could measure time with a 20pS hardware resolution even though we only display 200pS resolution. Well it does not display time at all ... it displays length with 0.00001" resolution, elongation, load, or stress.

dan

EDIT: on second thought, yes i did design it, since the only thing i kept was the case and keyboard.