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The Hybrid III family of dummies is used to estimate the response of an occupant during a crash. One recent area of interest is the response of the neck during air bag loading. The biomechanical response of the Hybrid III dummy's neck was based on inertial loading during crash events, when the dummy is restrained by a seat belt and/or seat back. Contact loading resulting from an air bag was not considered when the Hybrid III dummy was designed. This paper considers the effect of air bag loading on the 5th percentile female Hybrid III dummies. The response of the neck is presented in comparison to currently accepted biomechanical corridors. The Hybrid III dummy neck was designed with primary emphasis on appropriate flexion and extension responses using the corridors proposed by Mertz and Patrick. They formulated the mechanical performance requirements of the neck as the relationship between the moment at the occipital condyles and the rotation of the head relative to the torso.

The SID-IIs is a small [s], second-generation [II] Side Impact Dummy [SID] which has the anthropometry of a 5th percentile adult female. It has a mass of 43.5 kg, a seated height of 790 mm, and over 100 available data channels. Based on the height and mass, this is equivalent to an average 12-13 year old adolescent. The state-of-the-art SID-IIs has special application in evaluating the performance of side impact airbags. The dummy has undergone prototype testing and will shortly be available for worldwide evaluation. This paper describes the technical details of the dummy, its biomechanical design targets, how well it met those targets, its validation requirements, and its instrumentation. The dummy is the product of a joint development agreement between the Occupant Safety Research Partnership (OSRP) of USCAR and First Technology Safety Systems.

Energy management materials are widely used in automotive interiors in instrument panel, knee bolster, and door absorber applications to reduce the risk of injury to an occupant during a crash. Automobile manufacturers must meet standards set by the National Highway Traffic Safety Administration (NHTSA) that identify maximum levels of injury to an occupant. The recent NHTSA upgrade to the Federal Motor Vehicle Safety Standard (FMVSS) 201 test procedure(1) for upper interior head impact protection has prompted energy management materials' use in several new areas of affected vehicles. While vehicle evaluations continue, results to date show that energy management foams can be effective in reducing the head injury criterion [HIC(d)] to acceptable government and OEM levels.

Restraint systems play an important role in managing the energy of occupants during a crash event. Belt and airbag systems complement each other in order to gradually decelerate the occupant. However, the seating position of the 5th percentile female and 50th percentile male occupants forces the need to manage this energy in different ways. MADYMO simulation of a generic vehicle-restraint system with a driver side 5th and a 50th percentile Hybrid III dummy were done for a typical frontal impact. The belt system had a retractor/load limiter, but no pretensioner. The effect of airbag fabric porosity, inflation rate and seat belt load limiting ability were evaluated for both occupants. Parameters examined that affect system rebalancing to achieve the highest star rating were HIC and 3ms Chest acceleration.

This paper presents a 2D model for frontal vehicle-to-vehicle crashes that can be used for fleet modeling. It presents the derivational details and a preliminary assessment of the model. The model is based on rigid-body collision principles, enhanced adequately to represent energy dissipation and lateral engagement that plays a significant role in oblique frontal vehicle-to-vehicle crashes. The model employs the restitution and the apparent friction in order to represent dissipation and engagement respectively. It employs the impulse ellipse to identify the physical character of the crash, based on the principal directions of impulse. The enhancement of the rigid body collision model with restitution and apparent friction is based on collision simulations that use very simple finite element vehicle representations. The dependence of the restitution and the apparent friction on the incidence angle, the frontal offset, and the mass ratio, as predicted by the 2D model, has been presented.

The paper presents a comparison between the acceleration pulses of vehicle-to-vehicle crash tests with those of different single-vehicle crash tests. The severity of the full frontal rigid barrier test is compared with that of the vehicle- to-vehicle crash test based on average acceleration and time-to-zero-velocity. Based on this a 30mph full frontal rigid barrier test is found equivalent to a 41mph vehicle-to-vehicle crash. A reduced speed of 22mph for full frontal rigid barrier test is found to represent vehicle-to- vehicle crashes with 50%-100% overlap, with each vehicle travelling at 30mph. The paper also presents a comparison of the acceleration pulses from different crash tests based on the pulse shape and the pulse phase cross-correlation. None of the single-vehicle crash tests have been found to resemble vehicle-to-vehicle crashes in terms of the pulse shape and the pulse phase.

Stochastic simulation is used to account for the uncertainties inherent to the system and enables the study of crash phenomenon. For analytical purposes, random variables such as material crash properties, angle of impact, human response and the like can be characterized using statistical models. The methodology outlined in this approach is based on using the information about the probability of random variables along with structural behavior in order to quantify the scatter in the structural response. Thus the analysis gives a more complete picture of the actual simulation. Practical examples for the use of this technique are demonstrated and an overview of this approach is presented.

In 1997 Mertz, Prasad and Irwin [1] have described a technique for the development of injury risk curves for measurements made with the CRABI and Hybrid III family of biofidelic child and adult dummies that are used to evaluate restraint systems in frontal collision simulations. They further developed normalized injury risk curves for neck tension, neck extension moment, combined neck tension and extension moment for adults and children. The approach described by Mertz et al [1], is based on lines of equivalent stress and uses the maximum normal stress theory of failure to impose limits of the risk of injuries. In this paper a complementary approach is described based on the maximum energy of failure and lines of constant energy. A special case of this approach in 1D is used to develop the assessment values obtained by Mertz et al [1]. Limitations and advantages of the energy based approach are described, with especial emphasis on future implementation.

This technical paper presents the results from tests conducted with the ES-2re, a version of the ES-2 side impact dummy that was modified by the National Highway Traffic Safety Administration (NHTSA) to improve its performance in crash tests. Through the series of biofidelity tests conducted on the ES-2re, described in International Standards Organization (ISO) Technical Report (TR)9790 (1999), the OSRP observed a final overall biofidelity ranking of 4.1 for the ES-2re, which corresponds to an ISO classification of “marginal.” The biofidelity of the ES-2re is compared to that of the ES-2 and the WorldSID. Repeatability was also evaluated on the ES-2re based on the biofidelity test data. Additional pendulum tests were performed to assess the response of the dummy in oblique loading conditions, and results indicate that oblique loading from the front leads to significantly reduced rib deflections.

Regression models are used to understand the relative fatality risk for drivers in front-front and front-left crashes. The field accident data used for the regressions were extracted by NHTSA from the FARS database for model years 2000-2007 vehicles in calendar years 2002-2008. Multiple logistic regressions are structured and carried out to model a log-linear relationship between risk ratio and the independent vehicle and driver parameters. For front-front crashes, the regression identifies mass ratio, belt use, and driver age as statistically significant parameters (p-values less than 1%) associated with the risk ratio. The vehicle type and presence of the ESC are found to be related with less statistical significance (p-values between 1% and 5%). For front-left crashes the driver risk ratio is also found to have a log-log linear relationship with vehicle mass ratio.