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The determination of delta-V from the Barrier Equivalent Velocity (BEV) using energy analysis techniques such as CRASH3 is common in the field of accident reconstruction. This paper introduces a new methodology for determining delta-V in the field of accident reconstruction. Specifically it will introduce a linear analysis technique which utilizes the time to common velocity associated with two vehicles involved in an impact. This method employs all the assumptions used in the derivation of the CRASH3 damage based solution but rather than using an energy based solution a linear Barrier Equivalent Time (BET) method will be employed. This method requires the BEV, and thus the BET, of one of the vehicles involved in a collision and either the stiffness or the crush of the other vehicle. Instead of calculating the energies involved in the collision, the BET is used in conjunction with the time to common velocity in the impact.

Collision performance of automotive seat systems has been a subject of inquiry since crash research was in its infancy. However, when federal standards were initiated in 1968 regarding seat system performance, they became the baseline for automotive design, and later became the topic of numerous debates in terms of occupant crash force and energy management. This subject of energy management as it relates to seat design has been extended and expanded in the current time period. This paper will discuss current design trends in automotive seat design collision performance in terms of new data recently becoming available. Also, due to recent proposals and discussion regarding modification of FMVSS 207, a review of seatback performance data in a dynamic environment will be presented. Any proposals regarding the modification of FMVSS 207 require careful evaluation and quantification of seat system goals.

The CRASH3 damage algorithm is widely accepted as being reasonably accurate in the field of accident reconstruction, however there has been very little objective validation studies completed. The basis of the algorithm is Newton’s Third Law of Motion which in essence states that forces between interacting bodies are equal in magnitude, opposite in direction and collinear. Therefore, the forces should be theoretically equal and opposite when applying the damage algorithm. By applying the force balance method in determination of crush stiffness coefficients, the CRASH3 algorithm is forced to comply with its own derivation and should produce the most accurate result possible for the provided input. The purpose of this paper is to examine the results of the application of the force balance method in determination of stiffness coefficients (and therefore is ΔV) in real car-car tests and Federal Motor Vehicle Safety Standards side-impact tests (FMVSS 214).