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Computer simulations of occupant dynamics are ideal for conducting parametric studies evaluating injury countermeasures. A rollover accident was selected from the National Accident Sampling System (NASS) for simulation to validate the Articulated Total Body (ATB) model's capability to predict occupant dynamics during rollover accidents and to gain insight into injury mechanisms. Simulations of both the driver and passenger occupants which may be used in future countermeasure studies are performed. In the selected accident, a pickup truck rolled multiple times, the belted driver had minor injuries and the unrestrained passenger was ejected with fatal injuries. The body properties for both occupants were obtained using the Generator of Body Data (GEBOD) program based on their weights, heights, and sexes. The interior configuration of the vehicle compartment was modeled based on measurements taken from another vehicle of the same model.

Critical in vehicle crash simulations, human body data sets include mass, moments of inertia (MOIs), and ellipsoid size for each body segment, and location and resistive torque properties for each joint. The Generator of Body Data (GEBOD) program generates these human data sets for use in multibody programs. The objective of this study was to validate GEBOD estimates by directly measuring whole-body inertial properties of 69 volunteers and comparing the results with values calculated by the Articulated Total Body (ATB) model using GEBOD data sets. While the predicted whole-body center of gravity (CG) averaged within 1 cm of the measured values in the horizontal direction, vertically the errors were much larger. The predicted principal MOI were consistently 5%-30% lower than the measured values.

Sophisticated computer simulation of human response during various violent force exposure situations requires not only the validated programs, but also high quality databases, especially the data sets that characterize human body structures. Although anthropometric surveys and stereophotometric studies have been performed to create geometric and inertial property databases for the human body, there have been limited efforts on establishing the joint kinematics and resistive torque data sets. This paper presents the development, implementation, and validation of the human articulating joint model parameters for crash dynamics simulations. Measured human joint data on the voluntary range of motion and passive resistive torques were used to mathematically model the shoulder, elbow, hip, knee, and ankle joints.

The objective of this study was to mathematically model several proposed vehicle glazing materials using derived force-deflection characteristics, validate the models' dynamic behavior, and use the resulting glazing models in simulations of occupant dynamics during vehicle rollover. Simulations were performed with the three-dimensional, multibody dynamics program, the Articulated Total Body (ATB) model. The contact characteristics of side windows of tempered glass; polymethyl methacrylimide, also referred to as PMMI; and polycarbonate; as well as windshields from Ford Tempos and Jeeps, were developed from headform impact tests. These characteristics were first validated by performing simulations of the headform impact tests, and were then included in rollover simulations. Previously validated simulations of belted driver and unbelted passenger dynamics during an actual rollover accident were used as the baseline simulations.

In order to validate a Hybrid III dummy analytical simulation data set, a sled impact test was simulated in which both a Part 572 dummy and a Hybrid III dummy were used. Each dummy was restrained with a three-point belt system during the 32G sled test. The Crash Victim Simulator (CVS )/Articulated Total Body (ATB) model simulations were set up to reflect the same conditions as in the test and the previously developed standard Part 572 and the newly developed Hybrid III dummy body data sets were used. Graphics of the dummies' motion from the simulation are compared with films of the sled test. Accelerometer and load cell data from both the test and simulations are also used to demonstrate the validity of the CVS/ATB model for simulating the Hybrid III dummy dynamics.

To demonstrate the Articulated Total Body (ATB) model's capability to predict complex rollover accidents, a rollover accident was selected from the National Accident Sampling System (NASS) and simulated. This paper focuses on the simulation of the vehicle's dynamics which can in turn be used to specify the vehicle motion for occupant simulations. The selected accident case involved a pickup truck, crashing at high speed and completing three rolls. The pickup truck was modeled as a single rigid segment with fifteen contact hyperellipsoids rigidly attached to it. These hyperellipsoids were sized and positioned to approximate the exterior surfaces of the pickup truck. The force-deflection functions were defined based upon previous simulations of rollover tests. The initial conditions were defined to match the data in the NASS accident report as closely as possible.

In order to understand an occupant's often violent and complicated motion during rollover accidents, the motion of an anthropomorphic dummy was predicted dynamically using a human body gross motion simulation program. The accuracy of the predicted motion was established by its favorable comparison to that recorded on high speed film during a 60 mph crash in which the vehicle rolled over four times. This vehicle motion was then modified to six other rollover crash situations for computer simulation. Significant changes in the predicted occupant motion were readily observed. Differences were also observed in occupant accelerations and impact and belt forces.

The capability to predictively simulate occupant dynamics in vehicle rollover crashes using the Articulated Total Body (ATB/CVS) model was validated using the results of two controlled automobile rollover crash tests. The ATB model requires the occupant's inertial, geometric, and resistive joint torque properties, the vehicle interior geometry and motion, the contact characteristics for the occupant and vehicle interactions, and the seat belt characteristics. The validation was done by first simulating one test and adjusting the contact and belt properties to obtain good comparison with the test results. Then subsequent tests were simulated using the same properties, but changing only the input vehicle kinematics. Each occupant simulation used the standard Hybrid III data set and measured vehicle interior geometry. The vehicle kinematics were generated by simulating the vehicle dynamics with the ATB model. In one rollover, roof crush significantly affected the occupant's motion.