Questions on the CCI Option

General Questions, answers and information related to the release of the msmac3D program.
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Questions on the CCI Option

Post by MSI » Tue Jun 23, 2009 5:43 pm

Questions about the CCI option:
CCI Question #1? I am reviewing a SMAC analysis which was run in McHenry and was wondering what the CCIX and CCIY variables represent? I am assuming it has something to do with the CG location but am not sure. If it does have to do with the CG I am not positive as to which direction from the default CG position positive and negative are. Any help on this matter is greatly appreciated.
CCI Answer #1 CCI is the Center of Collision Interface Option. In original SMAC and all other vehicles of SMAC beside mSMAC, the collision interface is locked to the CG of the vehicle. Sometimes when a collision is offset from the CG and/or runs very near the CG the collision interface may have problems. The CCIX & CCIY options are for changing the Center of Collision Interface. The option is explained in more detail in our paper "SMAC-97"

CCI Question #2 The paper helped but I have two more questions:
1. Does the impact force in a situation where the center of collision is moved, still act about the original CG of the vehicle.
2. Also, does the iteritive force calculation still take into account that the force being solved for is being calculated for an impact that is not directly centered over the true CG of the vehicle?

CCI Answer#2
1) yes
2) yes.
The CCI is for reference purposes only. The CG was used for the CCI in original SMAC for convenience and/or memory limitations. It created problems if the 'reference vectors' got near 90 degrees. Therefore we added the ability to move the CCI. For each 'reference vector' which interacts with a 'reference vector' on the other vehicle, an equilibrium force is determined based upon the distance of the equilibrium point from the undeformed periphery of each of the vehicles. Once a balance is found at the equilibrium point, the forces and moments are calculated relative to the CG.
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