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A relationship between the risk of significant thoracic injury (AIS ≥ 3) and Hybrid III dummy sternal deflection for shoulder belt loading is developed. This relationship is based on an analysis of the Association Peugeot-Renault accident data of 386 occupants who were restrained by three-point belt systems that used a shoulder belt with a force-limiting element. For 342 of these occupants, the magnitude of the shoulder belt force could be estimated with various degrees of certainty from the amount of force-limiting band ripping. Hyge sled tests were conducted with a Hybrid III dummy to reproduce the various degrees of band tearing. The resulting Hybrid III sternal deflections were correlated to the frequencies of AIS ≥ 3 thoracic injury observed for similar band tearing in the field accident data. This analysis indicates that for shoulder belt loading a Hybrid III sternal deflection of 50 mm corresponds to a 40 to 50% risk of an AIS ≥ 3 thoracic injury.

Measurement of chest compression is vital to properly assessing injury risk for restraint systems. It directly relates chest loading to the risk of serious or fatal compression injury for the vital organs protected by the rib cage. Other measures of loading such as spinal acceleration or total restraint load do not separate how much of the force is applied to the rib cage, shoulders, or lumbar and cervical spines. Hybrid III chest compression is biofidelic for blunt impact of the sternum, but is “stiff” for belt loading. In this study, an analysis was conducted of two published crash reconstruction studies involving belted occupants. This provides a basis for comparing occupant injury risks with Hybrid III chest compression in similar exposures. Results from both data sources were similar and indicate that belt loading resulting in 40 mm Hybrid III chest compression represents a 20-25% risk of an AIS≥3 thoracic injury.

Currently, one of the major challenges for automotive engineers is to provide additional protection to motor vehicle occupants involved in side-impact collisions. A considerable amount of research is being conducted into this problem by governments and motor vehicle manufacturers on a worldwide basis. Changes to the current safety standards relating to side impact protection have been proposed in both North America and Europe. The proposed standards involve the use of dummies in collisions between a moving barrier and a stationary test vehicle. A total of 22 side impact tests of production vehicles have been completed to date to assess the appropriateness of the test procedures developed in the U.S. and Europe in the context of the Canadian vehicle mix and associated side impact accident problem. Vehicle performance rankings provided by the two test procedures were found to vary greatly.

This paper presents the results of biomechanical testing of the SID-IIs beta+-prototype dummy by the Occupant Safety Research Partnership. The purpose of this testing was to evaluate the dummy against its previously established biomechanical response corridors for its critical body regions. The response corridors were scaled from the 50th percentile adult male corridors defined in International Standards Organization Technical Report 9790 to corridors for a 5th percentile adult female, using established International Standards Organization procedures. Tests were performed for the head, neck, shoulder, thorax, abdomen and pelvis regions of the dummy. Testing included drop tests, pendulum impacts and sled tests. The biofidelity of the SID-IIs beta+-prototype was calculated using a weighted biomechanical test response procedure developed by the International Standards Organization.

The responses of a 5th percentile female ATD in the driver and/or rear passenger positions of 56 crashes are described. The Transport Canada side impact programme consisted of LTV-to-car impacts, car-to-car impacts and IIHS barrier-to-car tests. The majority of the tests involved severe crash conditions for which the vehicles were not designed. The SID-IIs head, chest and abdominal responses were compared to determine the effects of the striking bullet geometry, the angle of impact, the impact point and the self-protective elements of the struck vehicle, including airbag technology and armrest designs. The SID-IIs head responses and deflection measures were sufficiently sensitive to discriminate between the various striking vehicles, crash configurations, airbag systems and armrest characteristics.

Child dummies were seated in size appropriate child restraints and exposed to in-vehicle, static, side mounted airbag deployments as well as full scale side impact crash tests. The child seat sample included rear and forward facing child restraints and booster seats. Anthropomorphic test dummies (ATD) included an 18 month infant and fully instrumented Hybrid III 3 year old and Hybrid III 6 year old child dummies. Preliminary results suggest that properly restrained infants and children occupying age appropriate child seats may receive some protective benefits from side airbags provided the child seat and the child occupant are correctly positioned.

The NHTSA’s final interim rule on advanced airbags describes two static out-of-position test procedures for the 5th percentile female dummy. Recent testing by Transport Canada suggests that the procedure described for the positions may not be representative of the worst case condition and may include elements that are not realistic for a 5th percentile driver. A modified positioning procedure which prioritizes chest placement and positions the steering wheel in a location that is compatible with the visibility and comfort requirements of a 5th percentile female driver is described. A modified chin on hub procedure is also described. Results of the modified procedures are compared to the NHTSA procedures for a number of late model vehicles.

Drawing on recent Canadian field collision investigations and crash testing using the SIDIIs dummy, the field experience and crash performance of side-mounted airbag systems are reviewed. All of the inflatable technologies tested demonstrated the ability to greatly reduce head injury potential. Further improvements to the design of inflatable head protection devices are required to better ensure they contain and protect the head of occupants seated in locations forward of the mid seat track. New moving deformable barrier designs, such as the one recently developed by the IIHS, appear to offer significant advantages over designs currently used to regulate side impact protection. Improving the level of protection against chest injury to car occupants in SUV-to-car side impacts represents a significant challenge.

In 1998, Rouhana et al. described development of a new device, called the IR-TRACC (InfraRed - Telescoping Rod for Assessment of Chest Compression). In its original concept, the IR-TRACC uses two infrared LEDs inside of a telescoping rod to measure deflection. One LED serves as a light transmitter and the other as a light receiver. The output from the receiver LED is converted to a linear function of chest compression using an analog circuit. Tests have been performed with IR-TRACC units at various labs around the world since 1998. A first-generation IR-TRACC system was retrofit into a Q3 dummy by TNO. Similarly, a mid sized male Hybrid III dummy thorax and a small female Hybrid III dummy thorax have been designed by First Technology Safety Systems (FTSS) such that each contains 4 second-generation IR-TRACC units. The second-generation IR-TRACC is the result of continued development by FTSS, especially in the areas of the analysis circuit, manufacturing and calibration methods.

This paper discusses an attempt to relate measured loading at the head neck junction of arestrained six year old ATD during a frontal crash, to the mechanism of upper cervical fracture dislocation in young children. Lap belt, lap shoulder belt anda four point restraint system are considered. The basis for the reconstructions is the fatal injury to lap-belt restrained young children seated in the rear seat of contemporary minivans. The study concludes that simple forces and bending moments measured on such an ATD may not provide a sufficient basis for judging the likelihood of such an injury. Suggestions for a more comprehensive injury analysis are made.

An objective, biomechanically based assessment is made of the risks of life-threatening brain injury of frontal crash test results. Published 15 ms HIC values for driver and right front passenger dummies of frontal barrier crash tests conducted by Transport Canada and NHTSA are analyzed using the brain injury risk curve of Prasad and Mertz. Ninety-four percent of the occupants involved in the 30 mph, frontal barrier compliance tests had risks of life-threatening brain injury less than 5 percent. Only 3 percent had risks greater than 16 percent which corresponds to 15 ms HIC > 1000. For belt restrained occupants without head contact with the interior, the risks of life-threatening brain injury were less than 2 percent. In contrast, for the more severe NCAP test condition, 27 percent of the drivers and 21 percent of the passengers had life-threatening brain injury risks greater than 16 percent.

The dilemma of using a shoulder belt force limiter with a 3-point belt system is selecting a limit load that will balance the reduced risk of significant thoracic injury due to the shoulder belt loading of the chest against the increased risk of significant head injury due to the greater upper torso motion allowed by the shoulder belt load limiter. However, with the use of air bags, this dilemma is more manageable since it only occurs for non-deploy accidents where the risk of significant head injury is low even for the unbelted occupant. A study was done using a validated occupant dynamics model of the Hybrid III dummy to investigate the effects that a prescribed set of shoulder belt force limits had on head and thoracic responses for 48 and 56 km/h barrier simulations with driver air bag deployment and for threshold crash severity simulations with no air bag deployment.

A professional high diver, instrumented with accelerometers, performed sixteen dives from heights between 27-57 ft. For each dive, he executed a 3/4 turn and landed supine on a 3-ft deep mattress which consisted of pieces of low-density urethane foam encased in a nylon cover. Using FM telemetry, sagittal plane decelerations were recorded for a point either on the sternum or the forehead. Impact velocities and corresponding stopping distances for the thorax and the head were calculated from high-speed movies of the dives. For a 57-ft dive, the impact velocity of the thorax was 41 mph with a corresponding stopping distance of 34.6 in. The peak resultant deceleration of the thorax was 49.2 g with a pulse duration of 100 ms. The maximum rate of change of the deceleration of the thorax was 5900 g/s. No discomfort was experienced as a result of this impact. The maximum forehead deceleration occurred during a 47.0-ft drop and exceeded 56 g with a Gadd Severity Index greater than 465.

Currently used criteria based on functions of spinal acceleration obtained from crash test dummies are shown to be invalid indicators of chest injuries in blunt frontal impacts. Cadaver impact data are analyzed; and injury is found to be a statistically significant function of chest deflection, chest depth, and cadaver age at death. Based on the resulting regression equations, injury-limiting chest deflections are recommended for various size test dummies. The recommendations apply only to test dummies that have significant thoracic biofidelity for blunt frontal impact. They are valid for environments which include signigicant blunt frontal impact. Their extension to other environments has not been validated.

Two Highway Safety Research Institute (HSRI) dummies were tested and evaluated. Based on the analysis given, the HSI dummy should not be used for vehicle qualification testing. However, many of its components offer viable alternatives for future dummy development. The dummy was found to have inadequate biomechanical fidelity in the head, neck, and chest, although its characteristics were very promising and, as a whole, biomechanically superior to the Hybrid II. Its repeatability and reproducibility in dynamic component tests were better than the Hybrid II dummy. In particular, the HSRI friction joints were outstanding in repeatability and had a significant advantage in usability in that they do not require resetting between tests. In three-point harness and ACRS systems tests, the values of injury criteria produced by the HSRI dummy were generally lower than those obtained with the Hybrid II, especially the femur loads in the ACRS tests.

Details of a new crash simulator and preliminary results from a series of cadaver knee impact experiments were presented at the Eighth Stapp Conference. During the past year additional data concerning injury to the knee-thigh-hip complex have been obtained, and the studies have been extended to consider impact to the chest. Results to date indicate that for knee impacts against a moderately padded surface it is not possible to predict whether failure of the patella, femur or pelvis will occur first, although in these studies femoral fractures occurred most frequently. A force of 1400 lb. is recommended at this time as a reasonably conservative value for the over-all injury threshold level. Volunteers tolerated impact loads to the knee of 800-1000 lb. For loads applied over the sternum through a 25-30 padded surface, static and dynamic thoracic stiffness characteristics were determined for a limited number of cadavers.

For prescribed test conditions, a procedure is given for estimating the response characteristics of an arbitrary chosen standard subject based on the measured responses of subjects with different physical characteristics. Simple model analysis is used to develop the relationships between the subjects' responses and their physical characteristics. This analysis assures dimensional correctness among the critical parameters. The technique is applied to force-time data obtained by the Association Peugeot-Renault for lateral thoracic impacts of cadaver specimens. An averaged, normalized response curve is given for each of two impact conditions. A response corridor is prescribed for each average curve. These corridors can be used to assess the efficacy of various proposed thoracic side impact test devices exposed to similar impact conditions.

A critical performance issue in the development of any air cushion restraint system is the dichotomy that exists between the inflation rate required to meet the 30 mph frontal, rigid barrier restraint performance requirements and the effect that this parameter has on increasing the risk of deployment-induced injuries to out-of-position occupants. In general, small cars experience greater vehicle deceleration levels than large vehicles in FMVSS 208, 30 mph frontal, rigid barrier tests due to tighter packaging of their front-end components. In order to meet the FMVSS 208 performance requirements for such cars, the small car air cushion must be thicker and inflated faster than the large car air cushion. Such air cushion technology will increase the risk of life-threatening, deployment-induced injuries to out-of-position occupants of the small car.

An analysis was done of published forehead head impact data from cadaver specimens. Only data that were sufficiently documented to allow duplication of the impact environment were used in the analysis. A Hybrid III head, a Part 572 head, a Repeatable Pete head and two WSU heads were subjected to the same impact environments as the cadavers. A comparison of peak resultant head accelerations indicated that the Hybrid III response was the most representative of the cadaver data. The Part 572 head produced accelerations which were greater than the responses of the cadavers. These results support the claim that the Hybrid III head's response is humanlike for forehead impacts.

A review and analysis of existing cadaver head impact data has been conducted in this paper. The association of the Head Injury Criterion with experimental cadaver skull fracture and brain damage has been investigated, and risk curves of HIC versus skull fracture and brain damage have been developed. Limitation of the search for the maximum HIC duration to 15ms has been recommended for the proper use of HIC in the automotive crash environment.