Comparing the Use of Dynamic Response Index (DRI) and Lumbar Load as Relevant Spinal Injury Metrics

Abstract : The two most commonly used injury criteria for Spinal injuries today are Dynamic Response Index (DRI) related to structural accelerations, usually of the seat pan, or even more directly, lumbar force measurements taken within the Hybrid-III ATD as the evaluation criterion. With respect to continued use of these two criteria for spinal injuries, this report examines the following aspects in detail: 1) Any existing correlation between Peak Lumbar loads and DRI for un-encumbered occupants, in the whole blast loading regime or at least within different loading regimes 2) Re-evaluate (1) for encumbered occupants, that is, with heavier upper torsos 3) Potential changes to DRI calculations and Injury Assessment Reference Value (IARV) thresholds for encumbered occupants 4) General discussion on continued use of DRI as a design criterion for spinal injuries given the availability of the more direct Lumbar load from fully encumbered ATDs in underbody blast testing.