RESEARCH - Occupants

The Importance of Crash Pulse Data When Analyzing Occupant Kinematics Using Simulations
EDC WP# 2000-2 Authors: Wesley D. Grimes, P.E., F. Denny Lee, Ph. D.

Computer simulations are frequently used to analyze occupant kinematics in motor vehicle crashes, including what they collide with during the crash and the severity of these internal collisions. From study of such occupant simulations, it is then possible to infer how the actual human occupants may have been injured in a crash. When using a simulation to study how occupants react in a vehicle crash, a crash-pulse is usually required as input to the occupant simulation model. This crash-pulse is typically generated from a study of the vehicle motion and acceleration during the crash. There are several different methods for obtaining such a crash-pulse which are in common use. Each of these methods produces a different shape for the crash-pulse, even with identical velocity changes for the vehicle. The time duration, maximum acceleration, and general shape of the crash-pulse may influence the predicted motion of the occupants. In this research, the GATB (Graphical Articulated Total Body) computer simulation model is used to study basic occupant kinematics using a variety of shapes for the crash-pulse, in order to determine how the specific shape of the crash- pulse affects the predicted occupant kinematics.

The Effect of Crash Pulse Shape on Occupant Simulations
SAE Paper No. 2000-01-0460 Authors: Wesley D. Grimes and F. Denny Lee

Computer simulations are frequently used to analyze occupant kinematics in motor vehicle crashes, including what they collide with during the crash and the severity of these internal collisions. From study of such occupant simulations, it is then possible to infer how the actual human occupants may have been injured in a crash. When using a simulation to study how occupants react in a vehicle crash, a crash-pulse is usually required as input to the occupant simulation model. This crash-pulse is typically generated from a study of the vehicle motion and acceleration during the crash. There are several different methods for obtaining such a crash-pulse which are in common use. Each of these methods produces a different shape for the crash-pulse, even with identical velocity changes for the vehicle. The time duration, maximum acceleration, and general shape of the crash-pulse may influence the predicted motion of the occupants. In this research, the GATB (Graphical Articulated Total Body) computer simulation model is used to study basic occupant kinematics using a variety of shapes for the crash- pulse, in order to determine how the specific shape of the crash-pulse affects the predicted occupant kinematics.

Using ATB Under the HVE Environment
SAE Paper No. 970967 Author: Wesley D. Grimes

The Articulated Total Body (ATB) program has been used to study occupant kinematics in motor vehicle collisions for several years. The ATB model is a complex 3-dimensional lumped-mass model available for many different computer systems, including the personal computer, and requires formatted data files for the data input. A new version of this model, Graphical Articulated Total Body (GATB), has been developed to be operated under the HVE (Human, Vehicle, Environment) computer environment. The GATB program uses the graphical system built into HVE. This aids in set up and execution of the model to study human occupants in motor vehicle collisions. This paper addresses the integration of the ATB model with the HVE environment and includes a validation study comparing the GATB results to those of the ATB program.

Evaluation of Experimental Restraints in Rollover Conditions
SAE Paper No. 952712 Authors: Mark W. Arndt, Gergory A. Mowry, Charles P. Dickerson, and Stephen M. Arndt

A controlled experimental program was conducted to determine the response of humans and a human surrogate with experimental lap belt restraints in -Gz acceleration environments. In the program, lap belt anchorage position (belt angle) and belt tension/slack were varied. Human volunteers were subjected to a static -1.0 Gz acceleration for each restraint configuration. A 95th percentile male Hybrid III dummy was subjected to a nominal 4.25 m/s (9.5 mph), -5 Gz impact while restrained by each restraint configuration. For the -Gz acceleration, significant changes in occupant head excursion were observed with varied lap belt configurations. In general, less pre-crash belt slack and higher lap belt angles produced significant reductions in occupant vertical excursions. This research provides data for use in evaluating or developing occupant survivability systems for rollover crash environments.

Using ATB in Collision Reconstruction
SAE Paper No. 950131 Author: Wesley D. Grimes

The Articulated Total Body (ATB) computer program, sometimes referred to as the Crash Victim Simulator (CVS), is a powerful tool to aid in studying occupant kinematics in motor vehicle collisions. There are many options available within the ATB/CVS model and associated utility programs, such as GEBOD, which allow an analyst to model specific collisions and occupants. This paper discusses ATB/CVS as a tool for use in collision reconstruction. Specific examples are presented in developing a crash pulse from vehicle simulation programs such as EDSMAC, SMAC, HVOSM, etc. Techniques are also presented for modelling other moveable objects within the occupant environment, such as a seat back, steering column, or intrusion into the occupant compartment. A series of programs to aid in setting up an ATB data file, the CAL-3D Users Convenience Package, is also discussed.