3.3.1 Side Impact Test Dummies and Injury Criteria

As stated above, the U.S. and EU side impact regulations use very different test dummies. In addition to SID and EUROSID-1, a third impact dummy known as BIOSID has undergone extensive use and evaluation. Schematics of these three dummies are shown in Figure 5. The University of Michigan Highway Safety Research Institute under contract with NHTSA developed SID in the 1979 to 1982 time frame. The EEVC developed the prototype EUROSID from 1983 to 1985 through several research laboratories. After preliminary evaluations, further refinements led to a production version known as EUROSID-1 in 1989. Major components of the BIOSID test dummy were developed by General Motors. The Society of Automotive Engineers (SAE) Side Impact Dummy Task Force completed the BIOSID development.

The injury criteria measured by SID in FMVSS 214 are TTI(d) and pelvic acceleration. TTI(d) was derived and validated from a large cadaver data base [9, pg.IIIB-34]. At the time of addition of the dynamic impact requirement for passenger cars to FMVSS 214, the agency believed that vehicles designed with countermeasures which reduce these injury criteria would more adequately protect humans against injury in side crashes than vehicles without these countermeasures.

As stated in Section 3.1, SID is designed to measure thoracic (TTI(d)) and pelvic acceleration. As detailed in Section 3.2, EUROSID-1 has additional measurement capabilities beyond those in SID. BIOSID measurement capabilities are analogous to those of EUROSID-1. Prior to issuance of the dynamic portion of FMVSS 214 for passenger cars, NHTSA initiated a research program to study all three side impact dummies to determine their potential for use in the regulation. The dummies were evaluated through laboratory and full vehicle crash tests [10, 11]. The biofidelity of EUROSID-1 and BIOSID as compared to SID were assessed based only on the TTI(d) and pelvic acceleration.

NHTSA used a parameter called coefficient of variation (CV%) to determine the repeatability of test results. A lower CV% indicates a more repeatable result. Pendulum tests showed that SID and BIOSID had similar coefficients of variation for rib, lower spine and pelvic responses. EUROSID-1 had a higher CV% for the lower rib, but much lower coefficients of variation for all other responses. In sled tests, essentially the same padding stiffness minimized the responses of all three dummies. In comparison to cadaver results, for sled impacts in a padded environment, SID and BIOSID showed good biofidelity for the responses measured. Because of difficulties with EUROSID-1 during testing, data was limited, thus making it difficult to determine the full biofidelity of this device. Only the SID and BIOSID were compared in the full scale vehicle crashes. The front seated dummies showed good agreement, but the rear seated dummies did not.

In general, the initial NHTSA evaluation of alternative side impact test dummies showed that BIOSID deserved consideration for possible future use in FMVSS 214 [9, pg.IIIB-59]. There was not enough information to make the same determination for EUROSID-1 and in addition it appeared likely that this device would undergo additional design changes.