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The SIMon (Simulated Injury Monitor) software package is being developed to advance the interpretation of injury mechanisms based on kinematic and kinetic data measured in the advanced anthropomorphic test dummy (AATD) and applying the measured dummy response to the human mathematical models imbedded in SIMon. The human finite element head model (FEHM) within the SIMon environment is presented in this paper. Three-dimensional head kinematic data in the form of either a nine accelerometer array or three linear CG head accelerations combined with three angular velocities serves as an input to the model. Three injury metrics are calculated: Cumulative strain damage measure (CSDM) – a correlate for diffuse axonal injury (DAI); Dilatational damage measure (DDM) – to estimate the potential for contusions; and Relative motion damage measure (RMDM) – a correlate for acute subdural hematoma (ASDH).

Forty-two side impact cadaver sled tests were conducted at 24 and 32 km/h impact speeds into rigid and padded walls. The post-mortem human subjects were instrumented with accelerometers on the ribs and spine and chest bands around the thorax and abdomen to characterize their mechanical response during the impact. Load cells at the wall measured the impact force at the level of the thorax, abdomen, pelvis, and lower extremities. The resulting injuries were determined through detailed autopsy and radiography. Rib fractures with or without associated hemo/pneumo thorax or flail chest were the most common injury with severity ranging from AIS=0 to 5. Full and half thorax deflections were computed from the chest band data. The cadaver test data was analyzed using ANOVA and logistic regression. The age of the subject at the time of death had influence on injury outcome while gender and mass of the subject had little or no influence on injury outcome.

A new biofidelity assessment system is being developed and applied to three side impact dummies: the WorldSID-α, the ES-2 and the SID-HIII. This system quantifies (1) the ability of a dummy to load a vehicle as a cadaver does, “External Biofidelity,” and (2) the ability of a dummy to replicate those cadaver responses that best predict injury potential, “Internal Biofidelity.” The ranking system uses cadaver and dummy responses from head drop tests, thorax and shoulder pendulum tests, and whole body sled tests. Each test condition is assigned a weight factor based on the number of human subjects tested to form the biomechanical response corridor and how well the biofidelity tests represent FMVSS 214, side NCAP (SNCAP) and FMVSS 201 Pole crash environments.

This study was conducted to collect data and gain insights relative to the mechanisms and factors involved in hip injuries during frontal crashes and to study the tolerance of hip injuries from this type of loading. Unembalmed human cadavers were seated on a standard automotive seat (reinforced) and subjected to knee impact test to each lower extremity. Varying combinations of flexion and adduction/abduction were used for initial alignment conditions and pre-positioning. Accelerometers were fixed to the iliac wings and twelfth thoracic vertebral spinous process. A 23.4-kg padded pendulum impacted the knee at velocities ranging from 4.3 to 7.6 m/s. The impacting direction was along the anteroposterior axis, i.e., the global X-axis, in the body-fixed coordinate system. A load cell on the front of the pendulum recorded the impact force. Peak impact forces ranged from 2,450 to 10,950 N. The rate of loading ranged from 123 to 7,664 N/msec. The impulse values ranged from 12.4 to 31.9 Nsec.

A summary of the efforts of the Biomechanics Working Group to complete the task given to it by the International Harmonized Research Activities Steering Committee to determine specifications for a Universal Side Impact Anthropomorphic Test Devices is presented. Topics discussed are the nature of the world side impact problem, the anthropometric characterization of the world population at risk, dummy impact response specifications, and necessary and appropriate injury criteria and performance levels.

A finite element model of the human thorax was merged with a rigid body finite element implementation of the Hybrid III dummy (after removal of the Hybrid III thorax) and the combined model is used in simulations of an out of position driver during airbag deployment. Parameters related to injury, such as A-P thorax deformation, Viscous Criterion, rib stress distribution and strain in the thoracic contents are used to quantify the thoracic injury response. Initial driver position is varied to examine the relationship between distance from the airbag module and thoracic injury risk. The potential for injury mitigation through modulation of airbag inflation after initiation is also investigated. The utility of the combined model as an effective tool for the analysis of occupant kinematics and dynamics, examination of injury mechanisms, and optimization of restraint system design parameters is demonstrated.

With the widespread use of supplemental restraint systems (airbags), occasional rare injuries have occurred because of the force associated with these systems upon deployment. Recent case studies have demonstrated forearm fractures associated with airbag deployment. The present study was conducted to determine the tolerance of the human forearm under a dynamic bending mode. A total of 30 human cadaver forearm specimens were tested using three-point bending protocol to failure at 3.3 m/s and 7.6 m/s velocities. Results indicated significantly (p < 0.01) greater biomechanical parameters associated with males compared to females. The bending tolerance of the human forearm, however, was found to be most highly correlated to bone mineral density, bone area, and forearm mass. Thus, any occupant with lower bone mineral density and lower forearm geometry/mass is at higher risk. The mean failure bending moment for all specimens was 94 Nm.

A study of frontal collisions using the NASS data base showed that there were four times as many arm injuries to belt restrained drivers who had an air bag deploy than for the drivers who were simply belted. By far, the distal forearm/hand was the most commonly injured region. Hard copy review identified two modes of arm injury related to the deploying air bag: 1) The arm is directly contacted by the air bag module and/or flap cover, and 2) The arm is flung away and contacts an interior car surface. Based on the field studies, a mechanical device called the Research Arm Injury Device (RAID) was fabricated to assess the aggressivity of air bags from different manufacturers. Results from static air bag deployment tests with the RAID suggested that the RAID was able to clearly distinguish between the aggressive and non-aggressive air bags. Maximum moments ranging between 100 Nm and 650 Nm, and hand fling velocity ranging between 30 and 120 km/h were measured on the RAID in these tests.

The purpose of this study was to investigate the use of the chestband in side impact conditions by conducting validation experiments, and evaluating its feasibility by conducting a series of human cadaver tests under side impact crash scenarios. The chestband validation tests were conducted by wrapping the device around the thorax section of the Side Impact Dummy at its uppermost portion. The anthropomorphic test device was seated on a Teflon pad on a platform to accept impact from the side via a pendulum system. Tests were conducted at 4.5, 5.7, and 6.7 m/sec velocities using round and flat impactors. Retroreflective targets were placed at each strain gauge channel on the edge of the chestband. The test was documented using a high-speed digital video camera operating at 4500 frames/sec. Deformation contours and histories were obtained using the chestband electronic signals in combination with the RBAND-PC software.

Injuries to the thorax and abdomen comprise a significant percentage of all occupant injuries in motor vehicle accidents. While the percentage of internal chest injuries is reduced for restrained front-seat occupants in frontal crashes, serious skeletal chest injuries and abdominal injuries can still result from interaction with steering wheels and restraint systems. This paper describes the design and performance of prototype components for the chest, abdomen, spine, and shoulders of the Hybrid III dummy that are under development to improve the capability of the Hybrid III frontal crash dummy with regard to restraint-system interaction and injury-sensing capability.

Accident cases are examined to determine the injury mechanism for foot/ankle moderate and greater injuries in vehicle crashes. The authors examine 480 in-depth cases from the National Accident Sampling System for the years 1979 through 1987. An injury mechanism - a description of how the foot/ankle physically interacted with the interior of the vehicle - is assigned to each of the injured occupants. For the accidents in which the 480 occupants were injured, the more prominent types of vehicle collisions are characterized.

Nineteen sled impact tests were conducted simulating a frontal collision exposure for an unrestrained driver. The deceleration sled buck configuration utilized the passenger compartment of a late model compact passenger vehicle, a rigid driver's seat, and a custom fabricated energy-absorbing steering column and wheel assembly. Sled impact velocities ranged from 24.1 to 42.6 km/hr. The purpose of the study was to investigate the kinematic and kinetic interaction of the driver and the energy-absorbing steering assembly and their relationship to the thoracic/abdominal injuries produced. The similarities and differences between human cadaver and anthropomorphic dummy subjects were quantified.

A number of tests conducted under the sponsorship of the FAT were reported in papers at two previous Stapp Conferences and an Experimental Safety Vehicle Conference. These tests featured human cadavers and three different Anthropomorphic Test Devices (ATD) designed for use in lateral impacts. Test subjects were placed in Opel car bodies and impacted laterally by CCMC moving deformable barriers. In the previous papers, the reported responses of the human cadavers had wide variability and none of the ATD's studied featured good biofidelity. In this effort, a reexamination of the available data was undertaken and the process and results of applying different analysis techniques to the cadaver data, which resulted in significantly reduced scatter and variability, are discussed. Comparisons of the impact responses of the cadavers and the NHTSA developed Side Impact Dummy are also made.

Since 1976, the National Highway Traffic Safety Administration (NHTSA) has pursued biomechanical research concerning lateral impacts to automotive occupants. These efforts have included (a) the generation of an experimental data base containing both detailed engineering and physiological responses of human surrogates experiencing lateral impacts, (b) the analysis of this data base to develop both an injury index linking the engineering parameters to an injury severity level and response corridors to guide in the design of a test dummy, and (c) the development and refinement of a side impact test dummy suitable for use in safety systems development and evaluation. The progress of these efforts has been periodically reported in the literature [1-17]* and these references document the evolutionary trail NHTSA has followed over the duration of this research program.

A series of seventy-two pendulum-type impact tests were performed on six NHTSA Side Impact Dummies (SID) to assess dummy repeatability and reproducibility. A quantity called the Normalized Integral Square Error (NISE) is used to quantify the difference between acceleration responses from repeat tests. Limits for the NISE are developed to define acceptable differences in terms of phase shift, amplitude, and shape. Results indicate that the SID is repeatable in all of the test cases considered and fairly reproducible in 90° lateral impacts although this is not shown conclusively. Before the testing could be performed it was necessary to correct several durability problems with the SID that were identified while early production versions of the dummy were being tested. These modifications are described briefly.

This paper is part of a four year study to systematically define side impact injury in terms of the kinetic response of a suitable anthropomorphic dummy. Last year a paper was presented at the Experimental Safety Vehicle Conference in Germany which analyzed side impact dummy response and injury prediction based on cadaver data generated by the Highway Safety Research Institute. These subjects were generally older than those discussed in the current paper. This paper includes data from a number of University of Heidelberg cadaver sled tests-including padding tests which we recently found to be (1) critical for a definitive analysis and (2) previously not available. Two advanced dummies, whose design specifications are based upon biomechanical data, are currently being evaluated by the biomechanical community. The two dummies are (1) a Side Impact Dummy (SID) designed by the Highway Safety Research Institute (HSRI) and (2) the Association Peugeot-Renault (APR) dummy from France.

Side impacts have been shown to produce a large portion of both serious and fatal injuries within the total automotive crash problem. These injuries are produced as a result of the rapid changes in velocity an automobile occupant's body experiences during a crash. Any improvement to the side impact problem will be brought about by means which will ultimately modify the occupant's rapid body motions to such a degree that they will no longer produce injuries of serious consequence. Accurate knowledge of both the body's motion and resulting injuries under a variety of impact conditions is needed to achieve this goal. Possession of this knowledge will then permit development of accurate anthropomorphic test devices and injury criteria which can be used to create effective injury countermeasures in vehicles.

A dynamic characterization of the human thorax, in the form of a digital impulsive response signature, has been obtained which links the acceleration response of the struck side with the far side of the thorax under side impact conditions. This dynamic characterization was obtained by a unique combination of digital convolution theory, least squares approximation techniques, and a digital set of cadaver impact data. It has proven itself accurate in predicting the maximum relative acceleration, velocity and displacement between the left and the right lateral aspects of the thorax for a variety of impact conditions including lateral pendulum impacts, lateral rigid walls impacts at 15 and 20 mph and lateral impacts into padded walls at 20 mph.

Analysis of experimental acceleration time history data obtained from a thoracic instrumentation array has been performed. The data were generated under test conditions which include realistic frontal impacts in belt, air bag, and steering column systems and side impacts with rigid and padded door structures. Data from frontal and lateral pendulum impacts were also included. The results demonstrate that the instrumentation array captures sufficient information from the impact event to allow prediction of resulting thoracic trauma, defined either as thoracic AIS or total number of thoracic fractures, using a single function for each injury measure. Each function is universal in the sense that it is valid for all test modes and directions of impact. A strategy for developing a surrogate thorax to implement this injury predictive methodology is discussed and preliminary specifications are presented.