Browsing by Author "Sono, T J"

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    An investigation of the forces within the tibiae at typical blast loading rates : with different boots
    (2014) Pandelani, Thanyani; Nurick, Gerald N; Sono, T J
    Anti-Vehicular Landmines (AVLs), underbelly Improvised Explosive Devices (IEDs) or side-attack IEDs are some of the major threats to military vehicles and their occupants (Ramasamy et al., 2011). The lower extremities of the occupants are very prone to injury, mostly caused by underbelly detonation of AVLs or IEDs due to their spatial proximity to the rapidly deforming floor of a vehicle in response to the threat mechanism. Lower limb surrogate legs, such as a Hybrid III or Military Lower Extremity (MiL-Lx) legs, are used to quantify the impulse loading on the lower extremities when subjected to the forces of the rapidly deforming floor. These surrogate legs are also used in laboratories for simulated blast loading tests and scaled field tests to evaluate protection measures for the lower extremities. In this study, the responses of the HIII and MiL-Lx surrogate legs were evaluated at several blast loading conditions using the Modified Lower Limb Impactor. The impact tests were conducted using a lower limb impactor with the leg mounted vertically and attached to the knee of the Anthropomorphic Test Device (ATD). The MiL-Lx leg is a recently developed surrogate which has limited evaluation across the loading conditions. This work evaluated the MiL-Lx leg across a range of velocities from 2.7 – 10.2 m/s. The study also included the evaluation of the response of the surrogate legs when fitted with two different types of combat boot. The current study shows that the response of the MiL-Lx leg compares satisfactorily with a previous study of a simulated blast at 7.2 m/s and the Post Mortem Human Subject (PMHS) corridors conducted at Wayne State University (WSU), Michigan, U.S.A. The MiL-Lx leg force-time trajectories from both the lower and upper tibia load cell were found to have distinct features that can be related to the impactor dynamics. This observation implies that the response of the legs can be used to deduce the dynamics of the impactor or deforming floor. The MiL-Lx leg results measured by the lower tibia load cell shows that the combat boots mitigate the peak tibia force and delay the time to peak force. However, the results from the upper tibia load cell show that the boots did not reduce high-severity force, but only the delays the time-to-peak force. The upper tibia load cell did not show any potential mitigation capability of the combat boots. The HIII leg force-time trajectories from both the lower and upper load cells showed a similar bell shape and duration but different magnitudes. Both the lower and upper tibia load cells of the HIII leg showed that the combat boots had mitigation capabilities. This is the first time that the lower tibia response of the MiL-Lx leg has been tested and analysed at a range of loading conditions. This has resulted in better understanding of the response of the MiL-Lx leg and will ultimately lead to better protection measures of the lower extremities.