Truck Crush Properties

General Questions related to the CRASH Program and clones
Damage Analysis & Momentum Based Analysis programs
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MSI
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Truck Crush Properties

Post by MSI »

Q: Any references on Truck crush properties?
A: In 2013 a paper was published which included Large Truck and Bus Crash Tests results.
Stiffness Coefficients of Heavy Commercial Vehicles SAE Paper 2013-01-0796
ABSTRACT:
  • Accident reconstruction specialists have long relied on postcrash deformation and energy equivalence calculations to determine impact severity and the experienced change in velocity during the impact event. In order to utilize post-crash deformation, information must be known about the vehicle's structure and its ability to absorb crash energy. The Federal Motor Vehicle Safety Standards (FMVSS), the New Car Assessment Program (NCAP), and the Insurance Institute of Highway Safety (IIHS), have created databases with crash testing data for a wide range of vehicles. These crash tests allow reconstruction specialists to determine a specific vehicle's ability to absorb energy as well as to generalize the energy absorption characteristics across vehicle classes. These methods are very well publicized.
    Crash tests of commercial vehicles, however, are less common; and as a result, current literature has more limited information on the energy absorption characteristics of heavy vehicles such as traditional heavy trucks, motor coaches, buses or cab-over trucks.
    This paper attempts to quantify energy absorption characteristics for the aforementioned vehicle types based on publicly available frontal-impact crash tests reports and videos of heavy vehicles. In addition, video image analysis was performed. The video image analysis is validated against a NHTSA full scale frontal barrier test and then extended to other videos. This paper presents the methodology and analytical process used to derive the stiffness coefficients.
    The findings and data presented in this paper will add to the body of knowledge for heavy vehicles, and may bear significant importance to the accident reconstruction field and the understanding of stiffness coefficients for heavy commercial vehicles until such time that additional full scale tests are performed and made publically available
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MSI
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Joined: Thu Jun 18, 2009 12:37 pm

Re: Truck Crush Properties

Post by MSI »

I had a user request i post up a summary of the results from the Truck Crush Properties paper and so will do below
  • (see post after this correction)
On reviewing the paper i encountered an error in the first part of the paper that needs correcting:
  • The paper states that Campbell is 'crush per unit width' NO! (this item from the paper is incorrect):
    • erroneous statement on Campbell.png
      erroneous statement on Campbell.png (18.86 KiB) Viewed 154 times
    Why wrong?
    • First it is the WRONG equation, here is from Campbell:
      campbell.png
      campbell.png (11.69 KiB) Viewed 154 times
    • Second, it ignores the MAJOR extensions which were made by Mchenry/CRASH to ADD "crush per unit width", generalization for car-to-car crashes, among many other extensions and refinements
    See SAE 750893
    • CRASH concept.png
      CRASH concept.png (38.91 KiB) Viewed 160 times
    And please see our forum post Crush Coefficients Conversions: CRASH (McHenry), Campbell, WinSMASH (Prasad) for conversions between the techniques which mentions the following:
    • difference in crush coeffieicnts.png
      difference in crush coeffieicnts.png (57.51 KiB) Viewed 160 times
For additional information on CRASH and the Prasad/NHTSA reformulations, please see Yes i know this may be nitpicking however if they either don't understand that CRASH is A,B coefficients and "per unit width" are by McHenry and NOT Campbell, they are sloppy and misguide their readers and one needs to be sure to double check their other work!
Question? Comment? Please email forum@mchenrysoftware.com. Also see the McHenry Forum Index
Visit McHenrySoftware.com for technical information & software.
(c) McHenry Software, Inc ALL Rights Reserved.

MSI
Site Admin
Posts: 1386
Joined: Thu Jun 18, 2009 12:37 pm

Re: Truck Crush Properties

Post by MSI »

Here is the summary of the Crush properties
  • (we have not verified/checked their work, they used video analysis so be sure to get paper to check/review their techniques)
    Truck Crush Summary.png
    Truck Crush Summary.png (40.9 KiB) Viewed 159 times
One thing to note/always check on Crush Coefficients:
  • what is the 'no damage intercept'?
    • A simply A/2B gives you the value for a given set of A, B values.
    • A lot of folks who sell coefficients force a 4-5 mph intercept
    • See our forum discussion on the "no damage intercept" for more information on the 'no damage intercept' concept.
    • Note in the list below the wide variation in the 'no damage' intercept.
    • There doesn't appear to be any rationale for these differences so realize, just as with normal vehicle CRASH coefficients:
    Be sure to check!
    • Here's a quick calculation of the values for 'no damage intercept' from the table in the report
      • Calc of no damage intercept.png
        Calc of no damage intercept.png (14.77 KiB) Viewed 148 times
Here's some of the raw data contained in the report:
  • Bus Crush.png
    Bus Crush.png (65.84 KiB) Viewed 159 times
    Volvo truck crush.png
    Volvo truck crush.png (121.98 KiB) Viewed 159 times
    mci 2000 crush.png
    mci 2000 crush.png (53.76 KiB) Viewed 159 times
    MCI 1999 crush.png
    MCI 1999 crush.png (56.7 KiB) Viewed 159 times
Question? Comment? Please email forum@mchenrysoftware.com. Also see the McHenry Forum Index
Visit McHenrySoftware.com for technical information & software.
(c) McHenry Software, Inc ALL Rights Reserved.

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