Making dynamic strain measurements

Discussion in 'The Projects Forum' started by lukemacdougall, Feb 3, 2011.

  1. lukemacdougall

    Thread Starter New Member

    Feb 3, 2011
    1
    0
    Hi All,

    I am in need of assistance making strain readings.

    I am a mechanical engineering student working on my senior design project. I will be building model bridges (actual bridges as in trusses, not circuits) and will be applying a side impact load to simulate a ship crashing into the span of a bridge. I would like to take strain readings in different sections of the bridge throughout the impact. Therefore I will need to take multiple strain readings simultaneously at a high frequency.

    I am basically starting from scratch for my project. Our school computers have LabVIEW software and we also have NI CB-68LP DAQ boards but that is all that I have. I have around $400-$500 total that I can spend on parts for my circuit, the remainder of my budget will be spent on other supplies.

    I have completely read up on what I need for the circuit but I am unable to find anything that fits within my budget. Does anyone know of any products that I could use to help me do my project?

    I basically need everything from bridge completion to signal conditioning.

    Thank you for your time!

    Luke MacDougall
     
  2. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    I think you actually have one of these, because having just the connector block would be weird. This one has 16 analog Inputs 16-bit, 250 kS/s, so the maximum recordable frequency will be 125kHz, but I am not sure if you have the exact model, so please find the specs.

    You have to find out what is the output of the strain gauges and build some amplifier or attenuator so that you can connect them to the A/D convertor.
     
  3. wayneh

    Expert

    Sep 9, 2010
    12,156
    3,064
    Just a thought: Accelerometers are pretty darn cheap these days. So are lasers, which you might use to measure deflection. Maybe you could use a bunch of these cheap tools somehow instead of strain sensors.

    Also, have you seen this:
    http://pdfserv.maxim-ic.com/en/an/AN871.pdf
     
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