Crashes: Faster Than the Blink of an Eye

General Crash Reconstruction Tecnhiques
Crash tests, Pole Impacts
MSI
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Crashes: Faster Than the Blink of an Eye

Post by MSI »

You may have heard that term.
  • A crash is faster than the blink of an eye
    • (but NOTE NOT instantaneous!)
We all (should) know crashes generally take 75 to 150 milliseconds (depending on configuration and other factors).
But
  • Have you ever quantified how fast is the blink of an eye?
Well on the NAPARS facebook page they did!
From the page:
  • Typical car crashes from first touch to separation last about 100 milliseconds (ms), or 0.100 seconds.
    Just one tenth of a second.
    (Brian Notes: Let me add here it's more like 75 to 150 milliseconds (depending on configuration and other factors))
    How fast is that really, though? For comparison,
    a conscious eyeblink from start to finish is about three times longer, lasting up to 400ms.
    Seeing the lid-speed compared to position is interesting - the lid accelerates during the first half of the travel downwards, reaching peak speed about midway down (almost 200mm/s or nearly one half mile per hour), then slows to the closed position. Much faster going down than up. Huh. The numbers pass the DIMS test: an eyelid moving 10mm in 1/10th of a second would be an average speed of 10mm/0.1s = 100mm/s, so peak speed of near 200mm/s make sense.
    At the bottom of the stroke, we know the lid has to reach zero speed, but the chart from this paper doesn't show that, perhaps due to the limitation of their 600 frame-per-second measuring device. I would call that lack of zero an "artifact of the test setup".
blink time.png
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