Evaluation of Dynamic Response and Brain Deformation Metrics for a Helmeted and Non-Helmeted Hybrid III Headform Using a Monorail Centric/Non-Centric Protocol

ABSTRACT Introduction The Advanced Combat Helmet (ACH) military specification (mil-spec) provides blunt impact acceleration criteria that must be met before use by the U.S. warfighter. The specification, which requires a helmeted magnesium Department of Transportation (DOT) headform to be dropped onto a steel hemispherical target, results in a translational headform impact response. Relative to translations, rotations of the head generate higher brain tissue strains. Excessive strain has been implicated as a mechanical stimulus leading to traumatic brain injury (TBI). We hypothesized that the linear constrained drop test method of the ACH specification underreports the potential for TBI. Materials and Methods To establish a baseline of translational acceleration time histories, we conducted linear constrained drop tests based on the ACH specification and then performed simulations of the same to verify agreement between experiment and simulation. We then produced a high-fidelity human head digital twin and verified that biological tissue responses matched experimental results. Next, we altered the ACH experimental configuration to use a helmeted Hybrid III headform, a freefall cradle, and an inclined anvil target. This new, modified configuration allowed both a translational and a rotational headform response. We applied this experimental rotation response to the skull of our human digital twin and compared brain deformation relative to the translational baseline. Results The modified configuration produced brain strains that were 4.3 times the brain strains from the linear constrained configuration. Conclusions We provide a scientific basis to motivate revision of the ACH mil-spec to include a rotational component, which would enhance the test’s relevance to TBI arising from severe head impacts.

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Comparison of Human and Hybrid III Head and Neck Dynamic Response

10.4271/861892 ◽

1986 ◽

Cited By ~ 25

Author(s):

Marjorie R. Seemann ◽

William H. Muzzy ◽

Leonard S. Lustick

Keyword(s):

Dynamic Response ◽

Head And Neck ◽

Hybrid Iii

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The influence of dynamic response and brain deformation metrics on the occurrence of subdural hematoma in different regions of the brain

Journal of Neurosurgery ◽

10.3171/2013.10.jns131101 ◽

2014 ◽

Vol 120 (2) ◽

pp. 453-461 ◽

Cited By ~ 25

Author(s):

Andrew Post ◽

T. Blaine Hoshizaki ◽

Michael D. Gilchrist ◽

Susan Brien ◽

Michael D. Cusimano ◽

...

Keyword(s):

Dynamic Response ◽

Subdural Hematoma ◽

Parietal Lobe ◽

Linear Acceleration ◽

Occipital Lobe ◽

Von Mises Stress ◽

Rotational Acceleration ◽

Brain Deformation ◽

Strain And Strain Rate ◽

The Brain

Object The purpose of this study was to examine how the dynamic response and brain deformation of the head and brain—representing a series of injury reconstructions of which subdural hematoma (SDH) was the outcome—influence the location of the lesion in the lobes of the brain. Methods Sixteen cases of falls in which SDH was the outcome were reconstructed using a monorail drop rig and Hybrid III headform. The location of the SDH in 1 of the 4 lobes of the brain (frontal, parietal, temporal, and occipital) was confirmed by CT/MR scan examined by a neurosurgeon. Results The results indicated that there were minimal differences between locations of the SDH for linear acceleration. The peak resultant rotational acceleration and x-axis component were larger for the parietal lobe than for other lobes. There were also some differences between the parietal lobe and the other lobes in the z-axis component. Maximum principal strain, von Mises stress, shear strain, and product of strain and strain rate all had differences in magnitude depending on the lobe in which SDH was present. The parietal lobe consistently had the largest-magnitude response, followed by the frontal lobe and the occipital lobe. Conclusions The results indicated that there are differences in magnitude for rotational acceleration and brain deformation metrics that may identify the location of SDH in the brain.

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The Influence of Impact Angle on the Dynamic Response of a Hybrid III Headform and Brain Tissue Deformation

Mechanism of Concussion in Sports ◽

10.1520/stp155220120160 ◽

2014 ◽

pp. 56-69 ◽

Cited By ~ 1

Author(s):

Anna Oeur ◽

Blaine T. Hoshizaki ◽

Michael D. Gilchrist

Keyword(s):

Dynamic Response ◽

Brain Tissue ◽

Impact Angle ◽

Tissue Deformation ◽

Hybrid Iii

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The Influence of Striker Cap Size on the Dynamic Response of a Hybrid III Headform

Mechanism of Concussion in Sports ◽

10.1520/stp155220120176 ◽

2014 ◽

pp. 13-22

Author(s):

Lauren E. Dawson ◽

R. Anna Oeur ◽

T. Blaine Hoshizaki

Keyword(s):

Dynamic Response ◽

Hybrid Iii

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Effects of surface compliance on the dynamic response and strains sustained by a player’s helmeted head during ice hockey impacts

Proceedings of the Institution of Mechanical Engineers Part P Journal of Sports Engineering and Technology ◽

10.1177/1754337119871866 ◽

2019 ◽

Vol 234 (1) ◽

pp. 98-106

Author(s):

Santiago de Grau ◽

Andrew Post ◽

T Blaine Hoshizaki ◽

Michael D Gilchrist

Keyword(s):

Brain Injury ◽

Dynamic Response ◽

Ice Hockey ◽

Principal Strain ◽

Rotational Acceleration ◽

High Compliance ◽

Maximum Principal Strain ◽

Hockey Players ◽

Dependent Variables ◽

Hybrid Iii

In hockey, players experience different compliances during impacts to the head, from stiff ice to compliant collisions against other players. The objective of this study was to examine the effect of striking compliance in ice hockey impacts and its influence on dynamic response and brain tissue strain. Three striking caps of low, medium, and high compliances were used to impact a helmeted 50th-percentile Hybrid III headform. The headform was impacted at five locations at three velocities, representative of collision scenarios in hockey. The dependent variables, peak resultant linear and rotational acceleration as well as maximum principal strain were analyzed using a multivariate analysis of variance to determine significant differences between the compliances. The results indicated a significant effect of compliance on the responses of the headform. As expected, low-impact compliance resulted in higher linear and rotational accelerations when compared to the medium and high compliance conditions. However, while the linear and rotational acceleration responses of the medium and high compliance conditions would indicate a low chance of brain injury, the maximum principal strain magnitudes indicated a high likelihood of concussion. Medium- and high-impact compliances are a factor that has not been considered when designing and testing helmet technology in sport, with current methods reflective of low compliance surfaces, that is, those with high stiffness and rigidity. The results of this study demonstrate that an impact compliance is an important factor in producing brain injury and should be considered when certifying helmets through standard testing to mitigate the risk of brain injury.

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