Faculty Collaboration Database

Comparison of Axial Force Attenuation Characteristics in Two Different Lower Extremity Anthropomorphic Test Devices. Mil Med 2023 Nov 03;188(11-12):e3447-e3453

Date

08/08/2023

Pubmed ID

37552649

DOI

10.1093/milmed/usad310

Scopus ID

2-s2.0-85176509355 (requires institutional sign-in at Scopus site)

Abstract

INTRODUCTION: Any type of boot or footwear is designed to attenuate and distribute loading to the bottom of the foot. Anthropomorphic test device (ATDs) are used to assess potential countermeasures against these loads. The specific aims of this study were to compare and quantify force attenuation characteristics as a function of input energy for Hybrid-III and Mil-Lx ATD human surrogates.

MATERIALS AND METHODS: Two lower leg ATD surrogates (Mil-Lx and Hybrid-III) were tested to investigate the influence of a commercially available military boot on lower extremity force response and assess such differences against previously published postmortem human surrogate studies. The testing apparatus impacted the bottom of the foot using a rigid plate at velocities from 2 to 10 m/s. Tests were conducted on each ATD to obtain axial force response with and without boots as a function of input energy.

RESULTS: Peak forces ranged from 1 to 16.4 kN for the Hybrid-III, and 1 to 8.4 kN for the Mil-Lx for similar input conditions. The average force attenuation for the Hybrid-III at upper and lower load cells was 71% (59%-80%) and 70% (58%-78%). The average attenuation for the Mil-Lx at upper and lower load cells was 20% (13%-28%) and 37% (36%-37%), respectively. At the knee load cell, the attenuated peak loads ranged from 62% to 81% for the Hybrid-III and 16% to 30% for the Mil-Lx.

CONCLUSIONS: Force attenuation characteristics in the booted vs unbooted configuration of the Mil-Lx were significantly different than force attenuation characteristics of the H3 and may better represent in vivo forces during vertical impact injuries, such as IED blasts. Hence for military relevant applications where boots are used, the Mil-Lx may provide a more conservative evaluation of lower extremity protection systems.

Author List

Chirvi S, Pintar FA, Yoganandan N, Joseph McEntire B

Authors

Frank A. Pintar PhD Chair, Professor in the Biomedical Engineering department at Medical College of Wisconsin
Narayan Yoganandan PhD Professor in the Neurosurgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Accidents, Traffic
Biomechanical Phenomena
Explosions
Foot
Humans
Leg
Lower Extremity
Manikins