HYBRID III LOWER LEG INJURY ASSESSMENT REFERENCE CURVES UNDER AXIAL IMPACTS USING MATCHED-PAIR TESTS

摘要

The objective of the present study was to derive injury probability curves applicable to the Hybrid Ⅲ dummy (also termedthe Anthropomorphic Test Device, ATD) lower leg under axial impacts for military applications. A matched-pair approachwas used. Axial impacts were delivered to below knee foot-ankle complex preparations of the lower leg of the ATD usingpendulum and custom vertical accelerator devices. Military boot was used in some tests. Post mortem human surrogate(PMHS) preparations were used as matched-pair tests for injury outcomes. The alignment was such that the foot-anklecomplex was orthogonal to the leg (below knee tibia-fibula complex), termed as the normal 90-90 posture. Injury outcomesfrom the biological surrogate focused on calcaneus and or distal tibia fractures with or without the involvement of articularsurfaces. Peak lower tibia load cell forces were obtained from matched-pair dummy tests. Injury and force data were paired,censoring was assigned based on injury outcomes and survival analysis was done using the Weibull distribution to derivedummy-based probability curves. Mean peak forces were extracted at 5, 10, 20 and 50% probability levels. Normalizedconfidence interval sizes (NCIS) at ± 95% level were computed to determine the tightness-of-fit of the confidence bands.The NCIS data ranged from 0.34 to 0.78 and a peak force of 8.2 kN was associated at the ten percent injury probability level.Other data and curves are given in the body of the paper. The present Injury Assessment Reference Curves and Values(IARC and IARV) may be used in future tests for advancing safety in military environments. These survival analysisprocesses and IARC and IARV data may also be used in other applications.