Global-local Modeling of Aircraft Occupant Safety Assessment during Ejection

The extreme ejection conditions in the fifth-generation fighter F-35 could lead to occupant injury. Rocket sled testing of ejection seat with manikins is limited in replicating human response. The current neck injury models and the injury criteria from automotive safety are inadequate for the ejection-related injury. We propose to integrate the global-to-local finite element models (FEM) and simulation environment demonstrated in Phase I to enable fast and accurate simulation of occupant ejection, injury estimation and damage assessment. In Phase I a fast-running global FEM established the restrained occupant dynamics during ejection and windblast and a local high resolution FEM analyzed the spinal injury biomechanics using global FEM boundary conditions. In Phase II we will create a GUI-driven software tool that will take the 50th male pilot occupant through the entire process of seat interaction with cushions and restraints, generate aerodynamic pressure and forces through CFD at a specified ejection test airspeed, exercise the Global pilot-seat FEM with inertial seat and CFD force data through the ejection parachute opening phase, identify the hard tissue injury hazard portions of the Global FEM occupant results, and then analyze in-depth those events through high resolution FEM to describe hard tissue material failures.