Computer Simulation Of An Aircraft Seat And Occupants In A Crash Environment

A three dimensional mathematical model of a seat, occupant(s), and restraint system has been developed for use in aircraft crashworthiness analysis. Programs SOM-LA (Seat/Occupant Model - Light Aircraft) and SOM-TA (seat/Aircraft Model - Transport Aircraft) combine a lumped parameter model of aircraft occupants with a finite element model of the seat structure. SOM-LA models a single occupant, whereas SOM-TA has the capability to model up to three passengers. The intent of these programs is to aid in evaluation of the performance of aircraft seat and restraint systems in crash environments. Because the programs have been written for use primarily by engineers concerned with the design and analysis of seats and restraint systems, an effort has been made to minimize the input that is required to describe the occupants. Characteristics of two standard occupants, one dummy and one human, are included within the program, and an option is provided to simulate other occupants by providing additional input data. The structural model includes beam elements and has a maximum capacity of approximately 450 degrees of freedom, as determined by array dimensions within the programs. The beam elements can accommodate large plastic deformations and include the capability for cross section reduction due to local instabilities.