Numerical Simulation of Out-of-Position Front Passenger Injuries in Frontal Crashes Using an Accurate Finite Element Model of the Cockpit Module

Michihiro Yamagishi; Jun Iyama; Toshihiro Araki; Sou Natori

doi:10.4271/2012-01-0552

While airbags are effective safety devices for reducing occupant injury level, front Out-of-Position (OOP) passengers can be injured by airbag deployment, for example, when a passenger's head is on the instrument panel surface at the time of the collision. Consequently, FMVSS 208 prescribes In-Position and OOP occupant safety performance, and vehicle manufacturers are continuing to develop optimal restraint systems for reducing injuries under both In-Position and OOP conditions.

In this study, a numerical simulation method for OOP front passenger injuries in frontal crashes is presented by using accurate finite element (FE) models of the airbag and the cockpit module. The main characteristics of the airbag model are: (i) the Finite Point Method is employed to simulate the flow of gas; (ii) the initial airbag shape is represented by a folding model; (iii) nonlinear anisotropic material properties of the airbag fabric are identified considering the fiber directions and hysteresis. The major features of the cockpit module are: (i) part shapes are represented accurately by a fine mesh; (ii) rupture of the material is described by element elimination.

This paper describes the simulation method along with several numerical simulation examples that are sufficiently accurate to provide design directions for occupant restraint systems, including OOP passenger safety. The simulation results show that the reaction force of the instrument panel has a significant influence on dummy injury readings as well as on the airbag pressure. This means that the deformation and rupture mode of the instrument panel surface are important factors affecting dummy injury readings.

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Numerical Simulation of Out-of-Position Front Passenger Injuries in Frontal Crashes Using an Accurate Finite Element Model of the Cockpit Module 2012-01-0552

SAE MOBILUS