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In need of a measuring a 100 ns force or pressure.

  1. Jun 18, 2013 #1
    As stated in the title, I am trying to send an ultrasonic pressure wave through a medium using a transducer. However, I am having trouble finding equipment or some type of method that measures within the 100 ns of the pressure applied. Digital Force Gauges and Impact Force Measurement systems have a sampling rate in the KHz.

    Any ideas or help would be greatly appreciated. Thanks.
     
  2. jcsd
  3. Jun 18, 2013 #2
    have you examined using a membrane or similar structure to offer mechanical advantage and exaggerate your wave by a set amount, thus allowing a less accurate sensor to measure it, or you could design your own device which would have a membrane attached to a rod leading to a rotating optical shaft encoder, so that when the membrane flexed under the pressure change it would move the rod as a lever, and then rotate the shaft by some quantity which could more easily be measured, this would operate the same way that the tympanic membrane and ossicles function in the ear....
     
  4. Jun 18, 2013 #3
    i just looked at an article and it offer another solution set however one that jumped out at me was the option of using a membrane as stated before but measuring the vibration across this using a laser which would pulse and take different quantity s of time to reach a detector based on the location of the membrane...
    http://nvlpubs.nist.gov/nistpubs/jres/106/5/j65fic.pdf
     
  5. Jun 18, 2013 #4
    Thanks for the help Deotheophilus. The ideas you presented were great, but I am unsure that the first idea would be able to measure displacements in the hundreds of nanometers. What material would exaggerate displacements in that scale for the shaft to read? I am also more interested in finding a finished product that might be able to measure the pressure for me. Building my own measuring equipment might slow down the design process of the project I am working on.
     
  6. Jun 18, 2013 #5

    boneh3ad

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    Piezoelectric pressure transducers perhaps? I'm not sure if they make them in the 20 MHz range (Nyquist) but they go at least up to the single MHz range so it's worth a look.
     
  7. Jun 18, 2013 #6
    What is the medium?

    100 nS is quite small. I don't have any solutions to offer. But the magnitude of measurement you require makes me wonder if some sort of optical method may be needed. The first thought to pop into my head was some application of a laser displacement sensor such as those made by Keyence and others. To measure the displacement of a vessel wall (or membrane, as others suggest) acted upon by pressure wavefronts. Calibration of displacement to pressure may be a tricky affair.

    Or perhaps some sort of dual polarized light arrangements to measure a phase shift between light beams as the wavefront distorts the light. Again...that calibration bugaboo. That is, if the polarized light phenomenon holds.

    Don't the espionage aficionados talk about bouncing a laser beam off of a target room's window and reading the resultant frequency changes (interpreted as speech patterns)? Maybe something...aw, heck, that calibration thing again.

    You'll probably have to assemble your smart friends around a bottle of booze to release the creative juices to solve this one. Or contact the Government Laboratories & NASA to see if someone has previously developed anything that may work.
     
  8. Jun 19, 2013 #7
    Thanks for your help. The material I am using is carbon fiber. All the research I have done has pointed to using an ultrasound piezoelectric measurement system.
     
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