Crush measuring when damaged part is removed

[Ben Sears]

I have actually have two things. We recently had a crash where I was able to use the polycam app to scan a car (before the Evidence Eradication team for whatever reason needed to cut the door off). I want to go back and also physically measure the crush but with the door cut off, is there a best practice for still getting the measurements (door is still with the vehicle now inside the vehicle)?

Also, I have had a heck of a time finding the crash test reports (w/o a fee) and finding crash tests for the same year/model of vehicle. I couldn't find any crash test data for the model of car. 2011 Infinity G37.

[Bob Anderson]

NHTSA's lack of a G37 in their model list indicates to me that that platform has been tested under another model and/or brand.

Back in the day, such sisters and clones vehicles were evident in the Mitchell Collision Estimating Guide indexes, as they would have the same Body Codes. Now-a-days, you may have to use Scalia Safety Engineering's Vehicle Year & Model Interchange List, or do a little digging around the internet.

Good luck!

[Medwell]

For crash test data, if your car is a 4 door sedan you would use results of crash testing carried out on 2008 Infiniti G35 4 door sedan - test 6241 and 6242 are the side and frontal impact test numbers respectively. As far as I know neither the G35/G37 2 door coupe nor the G37 hardtop convertible has never been crash tested. For side damage coefficients on the 2 door coupe you would have to go with tests on the Nissan 350Z or 370Z as closest, although if your case involves a G37 hardtop convertible I think you are SOL for side impact testing. You can buy the crush stiffness coefficients for the 2008 G35 sedan already calculated from Neptune Engineering (neptuneeng.com). Infiniti has a checkered history when it comes to model names. This car is generically called the G-series https://en.wikipedia.org/wiki/Infiniti_G_Line and the number after G is related to the engine size, but it's basically the same car from 2003 to 2015. Sisters and clones indicates that the clones are 2007-2008 G35, 2009-2010 G37, 2011-2012 G25 and G37, 2013-2014 G37, and 2015 Q40 (they changed from G to Q without changing the car). Plus the same Nissan RWD platform is also the basis of the G-series coupe (2 door), the Z car (Nissan 350Z and 370Z), the EX (EX35 and EX37), the 2003-2006 G35 sedan, & the 2006-2010 M35 and M45.

As far as measurements for crush, sometimes you can put the door back in place close enough to do your measurements the normal way. But it depends on what you mean by measurements. Are you talking about a measuring tape? Because maybe your Polycam scan is better than your tape. Best practice is probably to get your crush measurements from that scan you already have.

[mchenrysoftware]

Excellent informative responses!
I will also add that i agree the initial scan before door removal should provide a good basis for crush measurements.
And always keep in mind when doing damage analysis...
it ain't rocket science and so crude measurements are FINE
For additional info see:

• Damage analysis measurement detail requirements

and for additional background on Damaga analysis, be sure to also read

• Why was CRASH created?

Be SURE if data is available to also evaluate pre and post impact travel, gouges, tire marks, etc
Obviously if ONLY damage is all you have it can provide a basis for an approximation

Brian