- In my research I have found
- 1982 DOT HS 806 152 Accuracy & Sensitivity of CRASH by Smith and Noga which appears to show good correlation in the mid 60's DV.
- However, SAE 870045 Overview of the way [url=https://www.mchenrysoftware.com/board/viewtopic.php?t=585]CRASH/EDCRASH Computes DeltaV[/url] (Day and Hargens) states :
- "it (CRASH) overestimates the Delta V for major crashes (delta-V greater than 50mph" (no reference given).
- I have also found SAE 890738 Application & Misapplication of Computer Programs for Accident Reconstruction (also Day and Hargens) which states that
- Delta V outside of 10-40 mph "may be suspect" (no reference given).
- "These programs are best-suited for studying collisions in the tested range for DeltaV, approximately 10-40 mph. Results outside this range may be suspect
- And i expect WHY they stated "10-40 mph" that is because CRASH (and IMPAC) virtual damage analysis are based on full-scale crash tests, and the coefficients for these programs are based on generally the following:
- a single crash test at 35-40 MPH and
- an assumption for the 'no residual damage intercept' of 4-5 MPH.
And most crash tests (NCAP) are at around 35-40 MPH
sooooooo....
10 mph is (maybe?) in recognition of the 'no residual damage threshold were at 8-10 mph with no damage!
- See SAE 88-0223 Elastic Properties of Selected Vehicles by Navin, MacNabb & Miyasaki )
- Also see our 1997 SAE paper
- And i expect WHY they stated "10-40 mph" that is because CRASH (and IMPAC) virtual damage analysis are based on full-scale crash tests, and the coefficients for these programs are based on generally the following:
- First you will note that we have a topic related to your question, see:
and then also please note from our topic
and
- Damage analysis measurement detail requirements
Which includes:
- CRASH (on which all damage analyses techniques are based) was invented by Ray McHenry as a quick/fast way to get starting speeds for NHTSA to start a SMAC analysis!
- ...and yea, NHTSA decided crude was OK and good enough for their NASS statistical studies mainly because they simply wanted/needed uniform interpretation of crash evidence for their NASS statistical studies so they could look for trends, etc. etc.
- See our many papers on CRASH
- and let us importantly add...
- many 'instantaneous momentum exchange' analysis program vendors now try to bolster their results by including damage analysis results.
- Please exercise caution when using these (or ANY) techniques for crash reconstruction.
- Be sure to perform sensitivity tests on any results. See:
- many 'instantaneous momentum exchange' analysis program vendors now try to bolster their results by including damage analysis results.
- ...and yea, NHTSA decided crude was OK and good enough for their NASS statistical studies mainly because they simply wanted/needed uniform interpretation of crash evidence for their NASS statistical studies so they could look for trends, etc. etc.
- CRASH (on which all damage analyses techniques are based) was invented by Ray McHenry as a quick/fast way to get starting speeds for NHTSA to start a SMAC analysis!
- Damage analysis measurement detail requirements
___________________________________________________
For additional information, please see:
- The Algorithms of CRASH, paper presented at 2001 SECCC, Aug 2001
- NHTSA CRASH3 Technical Manual - 1986 NHTSA collection/summary of CRASH papers
- From the McHenry Forum Topic on CRASH:
- Why was the CRASH program created?
- What Speed Should I Use to Calculate CRASH3 A&B Coeff?
- Is CRASH damage analysis a virtual relationship?
- Should a CRASH type damage analysis include induced damage?
- What is the "No Damage Intercept" of CRASH
- Can You Use Maximum Crush For CRASH A&B Crush Coefficients?
- Crush Coefficients Conversions: CRASH (McHenry), Campbell, WinSMASH (Prasad)
..and more, see the McHenry Forum and specifically the McHenry Forum topic CRASH and Damage Analysis