HIC, HIC(15), HIC(36) all the same

[13craig13]

Hi all,

We use DIAdem to calculate HIC. When I was analysising some data I noticed that HIC, HIC(15), HIC(36) values were all the same, I think this is because the time period used to calculate the original HIC is less the 15ms. Is it possible for all the HIC values to be the same?

It was noticed that the peak where the time period was taken from, at one point was 36ms wide.

How does DIAdem calculate what t1 and t2 to use for the original HIC calculation?

Thanks

[Otmar]

Hello Craig,

The algorithm used to determine the HIC is found on page 8 of the attached PDF file.

Please check the manual and see if it answers your question. If you have further questions, please add them to this thread and I will get someone from DIAdem R&D to answer specifics.

Best regards,

     Otmar

[13craig13]

Thank you for the reply Otmar.

I have looked at the document before but it doesn't detail what t1 and t2 are, I know it all depends on the maximum accerlaration but how does DIAdem determine them?

Just knowing whether it is definitely possible to have the same value for HIC, HIC(15), HIC(36) would be a great help.

Thanks

[StefanZ]

Hello Craig,

yes, it is it is definitely possible to have the same value for HIC, HIC(15), HIC(36). The basic HIC calculation is searching the maximum value for the integration boundaries t1 and t2. If the difference between t2 and t1 is less than e.g. 36ms the HIC(36) has the same HIC value, t1 and t2.

If you would like to know how the HIC is computed in detail you can have a look at the FORTRAN code which has been also used in DIAdem.

http://www.nhtsa.gov/Research/Databases+and+Software/NHTSA+Tools+Fortran

An old but still very good explanation of the theoretical background of the HIC you can find here:

http://www.health.uottawa.ca/biomech/courses/apa6903/CrashTests%20and%20the%20HIC.pdf

Best regards

Stefan Zölsch

National Instruments Engineering GmbH & Co. KG  

Pascalstraße 18

D-52076 Aachen