We are looking for a software solution, but currently use hand calculations and FBD’s.
We currently utilize the work Watts and use energy methods to determine closing velocity from crush. He does cover sideswipes, but is brief about it.
The SAE papers go into more detail, but 2004-01-1185 utilizes in house code and presents the general methodology. They compare to EDSMAC and that codes predictions to experiments is not great as illustrated in one of their bar graphs.
The other paper, 1999-01-0094, provides more details about slip regions and a working example. However, the later paper, 2004-01-1185, makes critiques that may or may not be valid.
Ideally, we would like to model sideswipes with a degree of confidence that is verifiable to publications that provide experimental data.
From March 21, 2014 our email response:
A: 1st I hope you’re aware of the misleading statements about SMAC included in that book by Watts.
That may be an older version of the book so please let me know if he changed or updated the sections cited.
CRASH should NOT be used in side-swipe collisions. From the CRASH3 manual: (page 1.7 , underline added):
crash sideswipes.png (25.84 KiB) Viewed 1980 times
SMAC can be used for sideswipe collision but there are limitations, particularly for original SMAC and/or EDSMAC or other original SMAC clones.
If the sideswipe is a glancing collision with mainly compressive forces then SMAC should be fine.
The only possible issue might be if the sideswipe covers the entire side of the vehicle.
There may be issues with original SMAC due to the CCI (Center of Collision Interface) issue.
See our paper SMAC-97 with discussion about the collision interface.
See section DEFINITION OF THE COLLISION INTERFACE in paper SMAC-97, page 3
In a sideswipe collision if it scrapes all along the side the reference vectors may become near perpendicular near the ends due to the limitation of original SMAC (EDSMAC or other original SMAC clones) to allow the collision interface origin reference ONLY at the CG. msmac/msmac3D allows moving the CCI from the CG to other locations (like to the other side of the vehicle) to avoid the issue (if that is the issue/reason for a problem)
Secondly of the sideswipe includes interaction where part of the vehicles interlock (a SNAG)
Original SMAC (EDSMAC) can’t handle forces other than compressive collision forces whereas the SNAG option of msmac3D/msmac3D can handle that type of situation.
The msmac/msmac3D with the SNAG option was invented/created to model collision interactions which are not all compressive forces.
See the section in SMAC-97 paper on SUPPLEMENTARY IMPULSIVE CONSTRAINTS ON RELATIVE MOTION
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