CHAPTER IV. ANALYSIS OF CRASH TEST DATA

    This chapter analyzes available FMVSS 213 sled crash test data. These crash test data were use to compare the Hybrid III to the Hybrid II dummy and calculate the pass/fail rates. This chapter does not provide the comparison between the current bench seat and crash pulse to the proposed requirements because the agency has not conducted crash tests under the proposed seat assembly and sled crash pulse.


    A. Hybrid III vs Hybrid II

    The 9-month old dummy is not instrumented and is used to measure the head excursion. The Hybrid II 3- and 6-year-old dummies are instrumented to measure HIC and chest acceleration and are also used to measure head excursion and knee excursion. The Hybrid III child dummies (12-month-old infant (CRABI), 3-year-old, and 6-year old) are equipped with more instrumentation than the Hybrid II dummies. They can measure HIC, chest acceleration, chest deflection, and contain a more advanced and biofidelic neck design. The NHTSA's report titled 'A Comparative Evaluation of Hybrid II and Hybrid III Child Dummy Families" presents the comparison methodology and results in greater detail. The comparison report concludes that the Hybrid III and Hybrid II child dummies show a similar performance in the sled test environment, that the overall performance is repeatable, but that the Hybrid III dummies have more measurement capabilities.


    B. Pass/Fail Rate

    This section summarizes the pass/file rates from all the test data on Hybrid III dummies. Each CRS test has an equal weight in calculating the pass/fail rates. All the tests data available for this analysis are listed in Appendix A. There were repetitive tests for some types of CRS/belt/tether configurations. In this case, these repetitive tests are only counted as one test and the average injury values of these tests were used in the pass/fail rate calculation.

    12-month-old CRABI

    Table IV-1 summarizes the passing rate information for tests with the 12-month-old CRABI. Because of the small number of tests, the passing rates are for all of the CRS configurations combined. As shown, NHTSA tested 5 different CRS under the FMVSS 213 sled pulse with a CRABI in the rear-facing CRSs, 20 percent (1 test) of these CRS tests passed the Nij and 80 percent (4 tests) passed the chest g. There were 5 tests with a CRABI in the forward-facing CRSs (4 different CRS with 5 different configurations, see Appendix A). All these 5 tests failed Nij. About 60 percent (3 tests) of these forward-facing CRSs tests passed 390 HIC15 and 40 percent (2 tests) passed the chest g.

    Overall, about twenty percent (one test) of rear-facing CRS passed all the required ICPLs and non of the forward-facing CRSs passed the proposed ICPLs. Note that a total of 15 test data points were shown in Appendix A, but many of these tests were repetitive tests. Also note that all the chest deceleration injury values, both for the rear-facing and forward-facing tests, were not recorded. The number of tests is the number of CRS/Belt combinations (e.g., Century SmartFit/Lap belt). This number might not represent the number of different CRS tested.


Table IV-1 Pass Rates for 12-Month-Old CRABI

CRS
Orientation
# of
Tests
Injury Criteria
HIC15 Head Excursion
with/woTether
(mm)
Nij Chest
Acceleration
(g)
Chest
Deflection
(mm)
Knee
Excursion
(mm)
Standard   390 720/813 1 50 30 915
Rear-Facing 5 100% na 20% 80% na na
Forward-Facing 5 60% 100% 0% 40% na 100%*


    3-Year-Old Dummy

    Table IV-2 lists the pass rates for the Hybrid-III 3-year-old dummy in a forward-facing CRS. A total of 5 tests were used for this calculation (3 different CRS with 5 different configurations, see Appendix A). Eighty percent (4 tests) of the 3-year-old dummy tests passed the Nij requirement. Overall, 80 percent (4 out of 5 tests) of the CRS tests with a 3-year-old dummy passed all the proposed ICPLs.


Table IV-2 Pass Rates for Hybrid III 3-Year-Old Dummy

CRS
Orientation
# of
Tests
Injury Criteria
HIC15 Head Excursion
with/woTether
(mm)
Nij Chest
Acceleration
(g)
Chest
Deflection
(mm)
Knee
Excursion
(mm)
Standard   570 720/813 1 55 34 915
Forward-Facing 5 100% 100% 80% 100% 100% 100%


    6-Year-Old Dummy

    Table IV-3 lists the pass rates for the Hybrid-III 6-year-old dummy in a forward-facing CRS. A total of 15 tests were in this group. But, many of these were repetitive tests. These tests accounted for only 5 distinctly different CRS/Belt/Retractor configurations (4 different CRSs). About sixty percent of the tests passed HIC and 100 percent of the tests passed the chest g's and chest deflection. All of the five CRSs failed Nij. Overall, non of the 6-year-old dummy tests passed all the proposed ICPLs. Note that the average values were used for tests with the same configuration.


Table IV-3 Pass Rates for Hybrid III 6-Year-Old Dummy

CRS
Orientation
# of
Tests
Injury Criteria
HIC15 Head Excursion
with/woTether
(mm)
Nij Chest
Acceleration
(g)
Chest
Deflection
(mm)
Knee
Excursion
(mm)
Standard   700 720/813 1 60 40 915
Forward-Facing 5 60% 100% 0% 100% 100% 100%


    Weighted 6-Year-Old Dummy

    Table IV-4 lists the pass rates for the Hybrid-III weighted 6-year-old dummy in a forward-facing CRS. There were a total of 10 repetitive tests accounted for 3 different CRS/configurations (only two different CRSs). These 3 tests passed HIC, chest g's, and chest deceleration requirements. About 33 percent (1 test) failed Nij. The 2 tests passed the Nij all with a 10 percent compliance margin. Overall, 67 percent (2 tests) of weighted 6-year-old tests passed all the proposed ICPLs.


    Table IV-4 Pass Rates for Hybrid III Weighted 6-Year-Old Dummy

    CRS
    Orientation
    # of
    Tests
    Injury Criteria
    HIC15 Head Excursion
    with/woTether
    (mm)
    Nij Chest
    Acceleration
    (g)
    Chest
    Deflection
    (mm)
    Knee
    Excursion
    (mm)
    Standard   700 720/813 1 60 44 915
    Forward-Facing 3 100% 100% 67%* 100% 100% 100%