To investigate compatibility in a single case, it is possible to crash two vehicles against each other and evaluate the injury values and deformations in both vehicles. In the real accident world, infinite vehicle combinations are possible. This shows that it is difficult to gain compatibility evaluations by vehicle-to-vehicle crashes. Rather it is necessary to define a meaningful vehicle-to-barrier test. As already shown in previous publications, the first priority is to ensure sufficient survival space for the occupants. The current frontal offset test requirements use a deformable barrier face. Due to the limited energy absorption capability of the barrier face, the increase in energy absorption on collision is higher for heavier vehicles than for lighter vehicles. When two vehicles collide and if their closing velocity is less than their doubled design speed, then there is sufficient deformation energy available for this particular crash. This holds regardless of the mass ratio of the two vehicles. To avoid higher intrusions than in the barrier crash, it is necessary to have a compartment force sufficiently higher than the front end force level of the opponent car. Usually this is more challenging for the lighter car than for the heavier car. A mass-ratio of 1.6 seems to be a reasonable limit for compatible car-to-car collisions. There are several test procedures with potential to further investigate the compatibility issue, each having advantages and disadvantages: Full width rigid wall test including load cell wall (US NCAP); Full width deformable wall test including load cell wall (suggested by TRL with double honeycomb layer); Offset deformable barrier test including load cell wall; Progressive deformable barrier (PDB) including load cell wall; Progressive deformable barrier with a mass dependant impact speed; and Offset progressive deformable moving barrier. For the covering abstract see ITRD E825082.
Samenvatting