4N6XPRT StifCalcs®

FORCE BALANCE: Application of the Tool for the Determination of Closing Speeds

by Daniel W. Vomhof III, EIT

This is a “Support Page” for an upcoming article to be published by the same title.

At this time, the following is available for download:

Toyota Yaris Pre-Crash Photographs
(110 MB)
Kia Rio Pre-Crash Photographs
(154 MB)
Post-Crash Photographs
(210 MB)
Video - Full and 1/8 speed
(21.7 MB)
Crash Scene Documentation
Vehicle Data for Rio and YAris as contained in ARC-CSI conference data packetRio Damage Measurements
Yaris Damage Measurements
Force-Balance analysis based on Mapped vehicles

The individual Pre and Post Collision photographs of the vehicles taken by Daniel Vomhof III can be viewed below


Several SAE papers discuss the Force Balance method, among them – 970942 / 1999-01-0079 / 2005-01-1188 and 2005-01-1205.

Background and formula for the calculations can be found in Balancing Collision Forces in Crush / Energy Analysis by Nathan Shigemura and Andrew Rich available from the IPTM Webstore ( http://www.iptm.org/webstore/ ) under Crash Investigation Publications.

A PDF with the above step-by-step approach to using the Force Balance module can be downloaded from:

4N6XPRT StifCalcs® Force Balance Example

The PDF has the added pages of the Force Balance for these same two vehicles based on the Ford Mustang’s AVERAGE Crush.

For more on this new program, and to see a sample printout, please download the documents from the following links.

Download Software Order Form

4N6XPRT StifCalcs® page

StifCalcs NOW Contains a FORCE-BALANCE calculation module!!!

Download Force Balance Analysis Order Form


Sample StifCalcs® Print-outs

Sample printouts from various Conference ” Data Packets”

Utility Vehicle Rear Test Summary printout

StifCalcs FAQs

StifCalcs Manual (6-22-2011)

4N6XPRT StifCalcs® Overview