Repetitive impact exposure and characterization of stress-whitening of an American football helmet outer shell material

Krzemiński, D; Fernando, Brianna M.; Curtzwiler, Greg W.; Gould, Trenton E.; Piland, Scott G.; Rawlins, James W.

doi:10.1016/j.polymertesting.2016.08.019

Cited by 5 publications

(10 citation statements)

References 50 publications

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“…Several factors have been shown to influence the magnitude of an impact event and the resulting tissue strain value, such as impact location, impact duration, and impact velocity. 17,49,[68][69][70][71][72] Increased velocity has been demonstrated to increase the magnitude of the dynamic response and resulting MPS. 49,73 However, in this current study, both significant reductions and increases in MPS were observed at the lower, mid, and higher range of velocities, indicating velocity did not appear to affect the results.…”

Section: Discussionmentioning

confidence: 99%

“…In addition to impact location, a strong correlation has been shown to exist between increased impact duration, higher brain tissue strains, and corresponding risks of concussion. 1,28,72,[75][76][77][78][79] When impacting the headform fitted with the prototype helmet, impact duration often decreased in comparison with the commercial helmet impacts. However, in these cases, both significant increases and decreases in MPS were observed, indicating impact duration was not a factor in changing MPS under these conditions.…”

Section: Discussionmentioning

confidence: 99%

“…However, the use of a controlled laboratory setting for helmet impact performance testing is suitable because on-field impact scenarios and environmental conditions are highly variable. 72 The Hybrid III headform is an anthropometric test device that has been used to simulate on-field impacts in sport (American football for this study). However, these devices have their limitations in that they do not fully replicate individual characteristics known to influence impact response, such as impact awareness, differences in football player body build, neck strength, and so on.…”

Section: Limitationsmentioning

confidence: 99%

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The effect of a novel impact management strategy on maximum principal strain for reconstructions of American football concussive events

Taylor

Post

Hoshizaki

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part P:

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The purpose of this study was to test the effectiveness of a helmet to reduce maximum principal strain by decoupling the head–helmet interface in reconstructions of head-to-head concussive impacts in American football. The primary goal of the American football helmet has been protection of players against skull fractures and other traumatic brain injuries. The modern-day helmet has evolved and been designed to mitigate traumatic brain injury, but it does not offer optimized protection against concussive injury. Studies to determine the influence of decoupling strategies on changes to brain motion and the resulting influence on maximum principal strain, a metric associated with concussive injury, have not yet been examined under concussive impact conditions. In this study, 19 helmet-to-helmet concussive events from professional American football were reconstructed using a pneumatically driven linear impactor to determine the components (resultant and dominant) of linear and rotational acceleration. The University of College Dublin Brain Trauma Model was used to determine maximum principal strain values. A prototype helmet with a decoupling liner strategy was shown to significantly reduce maximum principal strain in seven of the head-to-head concussive impact reconstructions. In each case, the prototype helmet significantly reduced the dominant coordinate component of rotational acceleration. The results of this study indicate the potential of a helmet liner decoupling system in reducing maximum principal strain for reconstructions of concussive events in American football.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Limitationsmentioning

confidence: 99%

See 1 more Smart Citation

The effect of a novel impact management strategy on maximum principal strain for reconstructions of American football concussive events

Taylor

Post

Hoshizaki

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part P:

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“…However, the use of a controlled laboratory setting for helmet impact performance testing controls the wide variance reflected in on-field impact scenarios. 59 This study was conducted using one particular model of an American football helmet. Experimental data obtained using other football helmet models and helmets from other sports would further add to the context of this study.…”

Section: Limitationsmentioning

confidence: 99%

The relationship between directional components of dynamic response and maximum principal strain for impacts to an American football helmet

Taylor

Hoshizaki

Post

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part P:

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Impact parameters used to design the American football helmet and the parameters associated with mechanisms of concussive injury are not consistent. Head impacts resulting in concussive injury in football are characterized as events creating rotational motion of the head that generate brain tissue strain. The extent of tissue strain influences the resulting severity of injury. Helmet technology aimed to decrease brain tissue strain by reducing the extent of brain motion could help reduce injury risk. Current helmet performance and evaluation measures, such as peak resultant of linear and rotational acceleration, do not fully define directional brain motion and therefore cannot provide sufficient information for this type of improvement. This study was conducted to determine whether coordinate components (X, Y, and Z) of linear and rotational acceleration would correlate with maximum principal strain, a common measure of brain injury risk. Coordinate components define directional motion of the head and offer a specific design parameter more easily reduced using engineered structures than peak resultant acceleration. In addition to coordinate components, this study introduces the dominant component, defined as the coordinate component with the highest contribution to the resultant acceleration, for additional evaluation. The results show that the relationship between the X, Y, and Z coordinate components of acceleration and maximum principal strain is location- and direction-dependent. The study indicates a strong relationship between the peak resultant and dominant components of acceleration to maximum principal strain. Because the dominant component of acceleration accounts for direction and location, identifying the relationship between dominant acceleration and maximum principal strain demonstrates the potential use of this metric to improve future helmet innovation aimed at reducing tissue strain.

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“…[15][16][17][18][19][20][21][22][23][24][25][26][27] To save financial and temporal costs in the development phase of novel helmet component designs, it is necessary to evaluate the performance of individual components prior to integrating new components into existing helmet systems. Previous research has evaluated the performance of the external helmet shell, 15,[18][19][20]26 the internal padding, 17,[21][22][23]27,28 and the chin strap, 24,25 but the impact performance of a football facemask has received limited research attention. On field impact exposure research has demonstrated that 30%-40% of a season's worth of football head impacts occur to the front quadrant of the helmet system.…”

Section: Introductionmentioning

confidence: 99%

Development of a non-destructive method to measure football facemask stiffness

Bina

Batt

DesJardins

2018

Proceedings of the Institution of Mechanical Engineers, Part P:

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Despite heightened awareness of the need for more protective headgear in American football, facemask performance as an individual component of the helmet system has been overlooked. Current methods used to evaluate facemasks are ineffective in separating facemask performance from the performance of the full-helmet system. This article evaluates the use of a non-destructive, quasi-static loading method to measure the structural stiffness of 11 football facemask designs that represent various geometries and materials. The test method determined quantifiable differences in facemask stiffness, while limiting permanent facemask deformation to less than 3.175 mm. The reliability of the structural stiffness measurement process was assessed through a test-retest analysis of three facemask styles. The coefficient of variation for each style of facemask was between 1.1%-3.3%. This novel facemask stiffness test can be used for the nondestructive evaluation of facemasks by reconditioners, as well as facemask manufacturers to differentiate the potential impact performance of novel facemask designs.

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Repetitive impact exposure and characterization of stress-whitening of an American football helmet outer shell material

Cited by 5 publications

References 50 publications

The effect of a novel impact management strategy on maximum principal strain for reconstructions of American football concussive events

The effect of a novel impact management strategy on maximum principal strain for reconstructions of American football concussive events

The relationship between directional components of dynamic response and maximum principal strain for impacts to an American football helmet

Development of a non-destructive method to measure football facemask stiffness

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