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2447 Views 1 Reply Latest reply: Jun 27, 2014 2:42 PM by G.Catlin RSS
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Jun 26, 2014 9:47 PM

How to Measure Force from Vehicular Accidents

Hi Guys, a friend of mine came to me for advice about his project, I'm not sure why since I'm nowhere near an expert, but he's trying to make a project that measures the damage on vehicles during accidents.

 

I won't go into much detail, but what we need is a measuring device, that could measure the force experienced by the vehicle from different points. The sensors should be able to connect to a device or switch that is triggered by said force.

 

I've been told that an acceleromter would work for this, and I always thought accelerometers just made your phone flip automatically. Would accelerometers be a good fit for this? If yes, could someone briefly explain why it would work?

 

Thanks a lot!

  • G.Catlin Novice 1 posts since
    Jun 27, 2014
    Currently Being Moderated
    Jun 27, 2014 2:42 PM (in response to Riley)
    How to Measure Force from Vehicular Accidents

    An accelerometer uses internal measurements of displacement of an internal sprung mass to decide what forces are applied.  They are available in 1 to 3 axes of measurement, can have analog or digital (serial communications) output, cover a range of force limits (+/- 2g. +/- 18g, +/- 100g,...), and some can be told what range to cover.  Almost all have a tolerance for impact forces way above their measurement limit (1000g or more is tolerable for some devices).  They all have frequency limits to their capabilities so check the numbers and remember that only frequencies below the limit are going to be anywhere near accurate.  A metal on metal collision (bumper to guardrail) will need 20kHz bandwidth or more (at the bumper) to get good peak numbers.  A soft occupant hitting a soft dashboard may get by with a few hundered Hz of bandwidth.

     

    The phone has multiple axes of sensitivity and takes note of what axis is indicating closest to 1g (earth gravity) a couple of times a second and orients your phone as necessary.

     

    An instrumented vehicle will have fixed sensors that can show acceleration (+ or -) changes as the speed changes along each axis.  Useful but needing some interpretation.

     

    Try a free app for a smartphone that shows acceleration: try a Tricorder (for graphics) or Elixir (for numbers) or search "acceleration" for oodles of choices.  Some are "acceleration monitors" or logs that record data.

     

    Happy crashing.

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