Numerical Study of Head/Helmet Interaction due to Blast Loading

Zhang, Timothy G.; Satapathy, S.; Dagro, Amy M.; McKee, Philip J

doi:10.1115/imece2013-63015

Cited by 10 publications

(8 citation statements)

References 14 publications

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“…The forces impacting the blast-exposed soldiers from IEDs are approximately a magnitude higher than that of the athletes even while the athlete experiences high-velocity head impacts repetitively [ 8 , 9 ]. For example, the force experienced by a football running back (200 lb) being hit at full acceleration (5 m per s) by an opposing lineman (200 lb) approximates 800–1000 Newtons [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

A Proposed Mechanism for Development of CTE Following Concussive Events: Head Impact, Water Hammer Injury, Neurofilament Release, and Autoimmune Processes

et al. 2017

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During the past decade, there has been an increasing interest in early diagnosis and treatment of traumatic brain injuries (TBI) that lead to chronic traumatic encephalopathy (CTE). The subjects involved range from soldiers exposed to concussive injuries from improvised explosive devices (IEDs) to a significant number of athletes involved in repetitive high force impacts. Although the forces from IEDs are much greater by a magnitude than those from contact sports, the higher frequency associated with contact sports allows for more controlled assessment of the mechanism of action. In our study, we report findings in university-level women soccer athletes followed over a period of four and a half years from accession to graduation. Parameters investigated included T1-, T2-, and susceptibility-weighted magnetic resonance images (SWI), IMPACT (Immediate Post-Concussion Assessment and Cognitive Testing), and C3 Logix behavioral and physiological assessment measures. The MRI Studies show several significant findings: first, a marked increase in the width of sulci in the frontal to occipital cortices; second, an appearance of subtle hemorrhagic changes at the base of the sulci; third was a sustained reduction in total brain volume in several soccer players at a developmental time when brain growth is generally seen. Although all of the athletes successfully completed their college degree and none exhibited long term clinical deficits at the time of graduation, the changes documented by MRI represent a clue to the pathological mechanism following an injury paradigm. The authors propose that our findings and those of prior publications support a mechanism of injury in CTE caused by an autoimmune process associated with the release of neural proteins from nerve cells at the base of the sulcus from a water hammer injury effect. As evidence accumulates to support this hypothesis, there are pharmacological treatment strategies that may be able to mitigate the development of long-term disability from TBI.

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Section: Introductionmentioning

confidence: 99%

A Proposed Mechanism for Development of CTE Following Concussive Events: Head Impact, Water Hammer Injury, Neurofilament Release, and Autoimmune Processes

et al. 2017

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“…Zhang et al . also developed a numerical model to study the blast loading of the head for a front blast. They evaluated the effect of helmet padding on the reduction of transmitted load to head.…”

Section: Introductionmentioning

confidence: 99%

“…However, they reported that while the pads removed the underwash effect, they caused a stronger coupled motion of the helmet to the head, hence forming localized pressure regions because of the skull deformation. Zhang et al [15] also developed a numerical model to study the blast loading of the head for a front blast. They evaluated the effect of helmet padding on the reduction of transmitted load to head.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of brain tissue responses because of the underwash overpressure of helmet and faceshield under blast loading

Sarvghad-Moghaddam

Rezaei

Ziejewski

et al. 2016

Numer Methods Biomed Eng

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Head protective tools such as helmets and faceshields can induce a localized high pressure region on the skull because of the underwash of the blast waves. Whether this underwash overpressure can affect the brain tissue response is still unknown. Accordingly, a computational approach was taken to confirm the incidence of underwash with regards to blast direction, as well as examine the influence of this effect on the mechanical responses of the brain. The variation of intracranial pressure (ICP) as one of the major injury predictors, as well as the maximum shear stress were mainly addressed in this study. Using a nonlinear finite element (FE) approach, generation and interaction of blast waves with the unprotected, helmeted, and fully protected (helmet and faceshield protected) FE head models were modeled using a multi-material arbitrary Lagrangian-Eulerian (ALE) method and a fluid-structure interaction (FSI) coupling algorithm. The underwash incidence overpressure was found to greatly change with the blast direction. Moreover, while underwash induced ICP (U-ICP) did not exceed the peak ICP of the unprotected head, it was comparable and even more than the peak ICP imposed on the protected heads by the primary shockwaves (Coup-ICP). It was concluded that while both helmet and faceshield protected the head against blast waves, the underwash overpressure affected the brain tissue response and altered the dynamic load experienced by the brain as it led to increased ICP levels at the countercoup site, imparted elevated skull flexure, and induced high negative pressure regions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

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“…The effect of wearing a helmet, especially for short positive phase durations (0.5-5 ms), is a significant reduction in risk of blast brain injury at the crown of the head for overhead blast scenarios. In other orientations, blast wave measurements are complicated by the difference between reflective (measured with pressure gauges oriented parallel to the direction of the blast) and incident (measured with pressure gauges oriented perpendicular to the direction of the blast) pressures, leading to conflicted reports of helmets possibly increasing the risk of primary blast injury [36][37][38][39][40][41][42]. This risk has to be carefully evaluated because reflected pressure measurements can be two to eight times greater than incident pressure measurements for the same blast scenario [32].…”

Section: Discussionmentioning

confidence: 99%

Primary blast wave protection in combat helmet design: A historical comparison between present day and World War I

Eynde

Eckersley

et al. 2020

PLoS ONE

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Since World War I, helmets have been used to protect the head in warfare, designed primarily for protection against artillery shrapnel. More recently, helmet requirements have included ballistic and blunt trauma protection, but neurotrauma from primary blast has never been a key concern in helmet design. Only in recent years has the threat of direct blast wave impingement on the head-separate from penetrating trauma-been appreciated. This study compares the blast protective effect of historical (World War I) and current combat helmets, against each other and 'no helmet' or bare head, for realistic shock wave impingement on the helmet crown. Helmets included World War I variants from the United Kingdom/United States (Brodie), France (Adrian), Germany (Stahlhelm), and a current United States combat variant (Advanced Combat Helmet). Helmets were mounted on a dummy head and neck and aligned along the crown of the head with a cylindrical shock tube to simulate an overhead blast. Primary blast waves of different magnitudes were generated based on estimated blast conditions from historical shells. Peak reflected overpressure at the open end of the blast tube was compared to peak overpressure measured at several head locations. All helmets provided significant pressure attenuation compared to the no helmet case. The modern variant did not provide more pressure attenuation than the historical helmets, and some historical helmets performed better at certain measurement locations. The study demonstrates that both historical and current helmets have some primary blast protective capabilities, and that simple design features may improve these capabilities for future helmet systems.

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Numerical Study of Head/Helmet Interaction due to Blast Loading

Cited by 10 publications

References 14 publications

A Proposed Mechanism for Development of CTE Following Concussive Events: Head Impact, Water Hammer Injury, Neurofilament Release, and Autoimmune Processes

A Proposed Mechanism for Development of CTE Following Concussive Events: Head Impact, Water Hammer Injury, Neurofilament Release, and Autoimmune Processes

Evaluation of brain tissue responses because of the underwash overpressure of helmet and faceshield under blast loading

Primary blast wave protection in combat helmet design: A historical comparison between present day and World War I

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