Aircraft crash survivability from viscous injury in vertical impacts

摘要

This research investigated viscous injury from vertical impact loading to determine if itis critical to survivability of aircraft accidents. A unique database was built fromautopsy reports and accident investigations combining injury data with the vehicleimpact data. Computer models were created and used to assess injury potential.Common design limits and actual crash data from full scale research experiments wereused as inputs. The results were analyzed according to published injury thresholds andcompared with real accident autopsies to determine the validity of the hypothesis.Heart and Aortic Injury (HAI) has been considered a critical survivability factorthrough out the history of mechanized transportation. The mechanisms of HAI in theaircraft environment were never well characterized. Automotive research identifiedimportant HAI injury mechanisms related to the forward and lateral impact vectors.This research investigated the vertical impact vector. A model was developed toevaluate the biomechanical response of a simplified visco-elastic system, andincorporated into a system model which included the occupant and aircraft seat. Thisapproach was similar to the development of spine injury criteria and provided theadvantage of a macro level evaluation of the injury thresholds and assessment of thecriticality in survivable accidents.Evaluations of real accidents sustaining HAI characterized a range of impact severityand approximate boundaries for survivability with HAI and internal organ injury.Viscous injury potential from vertical impact was found to be less critical than potentialspine injury. Detailed analysis of HAI documented in autopsy reports and thecorresponding accident investigations found that HAI was associated with cockpitenvironmental factors rather than inertial displacement mechanisms. Verticaldisplacement of the heart due to inertial loads is not a critical factor in survivableaccidents given current aircraft technology. Inertial loading to the heart and aorta is acontributory factor for viscous injuries in aircraft accidents.