Bridge Rail Impact and Roll/Launch Off Bridge!

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MSI
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Bridge Rail Impact and Roll/Launch Off Bridge!

Post by MSI »

For the latest post on this topic which include some DRAFT simulations please click here or scroll to the bottom of this thread

Saw on LinkedIn some great graphics of scanned crash scene
2021-01-13_16-06-43.jpg
2021-01-13_16-06-43.jpg (37.91 KiB) Viewed 91 times
[COMMENT]
  • The vehicle movement and orientations on the link on the post (the picture above and others on the link) look wrong as they illustrated the vehicle traveling it launch over the barrier.

    Nice work on cloud data/illustration!
    However
    It drives us crazy such great graphics and poor quality vehicle movement (obviously the vehicle wasn't simulated for takeoff and landing)...
    The orientation in this display looks off (tire mark up wall means vehicle rolled driver side down (CCW) (see roll plots below) and then in the crash the vehicle must have pitched/rolled over barrier in such an orientation and with sufficient speed to land on wheels as indicated by the limited evidence they presented in the link you posted?

    Laser Cloud Scan Devices for crash reconstruction by FARO, LEICA,Trimble and others which are excellent for memorializing and presenting crash scene data and vehicle crush measurements HOWEVER i wish they'd
    add true scientific 3D Simulation.
    See our SAE paper 880228, which shows we've been simulating CMB and bridge rail crashes for decades so there is NO reason this crash couldn't have been easily simulated!
    The expert they worked with should have as a minimum looked at Texas. Nebraska or other full scale crash test facilities to find similar Concrete median Barrier or bridge-rail tests to calibrate and get a better baseline of the roll/pitch 'typical response' on barrier impacts and launch over a barrier.
    Nice graphics!
    Too bad primitive somewhat silly looking movements of the vehicle.

    The following is a figure from our SAE paper 880228 which shows, as you'd expect, that as you make a mark UP the barrier, the vehicle has to roll AWAY from the barrier.
    This is a comparisons of full scale crash tests with our msmac3D simulations (note msmac3D is a combination of SMAC and HVOSM).
    figure from SAE paper.jpg
    figure from SAE paper.jpg (113.42 KiB) Viewed 91 times
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MSI
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Re: Bridge Rail Impact and Roll/Launch Off Bridge!

Post by MSI »

Some back and forth on linkedin i'll summarize and my responses below.
  • They mentioned that the expert on the case was no slouch, and my comments weren't about the expert, it was about the technology!
    The vehicle movements were wrong from elementary physics (if the right side tires are leaving marks on a barrier, the vehicle MUST roll CCW! (as in driver side down))
    Also it appears the respondent on the thread was not trying to get any dialog mainly trying to escalate the situation.

Here are my 3 responses:

Response 1:
  • I find it truly sad that 3D graphics and 3D scanning technology make mighty purdy pictures and displays
    BUT
    Sir Isaac cries at the crude vehicle movements...
    The cloud companies (and experts) need to invest in true 3D simulation technology.
    (note: our operators are standing by :-O)
    FARO is so lame they advertise that a SINGLE EQUATION IS ADEQUATE FOR A RECONTRUCTION??
    cmon...
    Please see
Response 2:
Then the response on Linkedin was about case limiting budget, and my response:
  • I agree it may have simply been a case limiting simple illustration...i meant no insult to the expert on that illustration.
    However I suggest
    That any expert creating an illustration make the basic vehicle responses more realistic...
    like by using something like our msmac3D simulation program can easily handle that entire sequence...
      • msmac3D is not the only program available that can handle a barrier impact quickly and easily
      And for a demonstration of the ease of creating better vehicle movements send us
      • 1) an upload the bridge and landing area as a vrml (or something i can open in Rhino or similar and then export)
        2) include in a layer or DXF with the measured tire marks
        3) identify make/model/year of vehicle
        4) send any EDR data in CSV or as PDF report
      In a couple hours we can simulate it with msmac3D (main time is dealing with them HUGE scans...they're beautiful by HUGE)
      and not for a finalized version, just for guidance on how best to show to various positions.
    Then they can display a video with the proper scientifically correct trajectory into and up over the barrier and then down to the landing
    • looking at the exhibit i think that the vehicle more likely than not rolled on the flight to landing point, but would need to see damage evidence, etc (like undercarriage markings as it went over the barrier and landed)
    here's some samples we've done
Response 3:
To which the person responded that i devolved into a "SALES PITCH!" here was my response:
  • sales pitch? Ok maybe a wee bit...
    however also a wake up call!
    and a request for the surface/evidence data! (send it and i'll demonstrate a more realistic vehicle response!)
    The folks who actually need to be sold on simulation technology are the billion dollar cloud scan companies with their gorgeous graphics BUT simple elementary 'instantaneous momentum exchange' reconstruction techniques...
    WAKE UP and smell the technology!

    The video link I included was to show the 3D technology that has been available (and has been for decades note the wire form graphics is some of it!)
    It has been used to reconstruct crashes, design stunts and easily simulate barrier collisions
    BUT
    Them there billion dollar cloud companies focus on purdy pictures and ignore the need for valid 3D simulation models!
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MSI
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Re: Bridge Rail Impact and Roll/Launch Off Bridge!

Post by MSI »

NOTE: We need to add DRAFT to these types of visual displays of our 3D simulations.
  • We set them up mainly because we find something about the crash interesting.
    We don't have the measurements and other information to perform a proper reconstruction.
    We don't spend the additional time required to add the houses, background, etc
    This is simply a demonstration of the types of things our msmac3D simulation can bring to help our users understand 'what happened' and investigate the vehicle and crash dynamics.

Had a discussion with a colleague and decided to do a simple demonstration of what a concrete bridge rail impact looks like.
note the vehicle dynamics.
Took about an hour.
just grabbed an overhead of a bridge and put in elevations
Next will have to get a cloud scan graphics
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Re: Bride Rail Impact and Roll/Launch Off Bridge!

Post by MSI »

Had a little free time during lunch and took prior simulation, quickly replaced and changed the elevated roadway and launch
looked for some bridge models but none with curve in road (could have shown underside of bridge, etc).
Landing hard made for another interesting launch maneuver.
Don't have measurement/photographs of tire mark, landing area, damage areas on vehicle to try to match.
So simply tinkered a bit till got a dramatic launch and landing.
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