A Computational Study of Liquid Shock Absorption for Prevention of Traumatic Brain Injury

2020 ◽  
Author(s):  
Hossein Vahid Alizadeh ◽  
Michael G. Fanton ◽  
August G. Domel ◽  
Gerald Grant ◽  
David Camarillo
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
New Technologies ◽  
Computational Study ◽  
Impact Testing ◽  
American Football ◽  
Constant Force ◽  
Shock Absorption ◽  
Future Design ◽  
Football Helmets

Abstract Mild traumatic brain injury (mTBI), more colloquially known as concussion, is common in contact sports such as American football, leading to increased scrutiny of head protective gear. Standardized laboratory impact testing, such as the yearly NFL helmet test, is used to rank the protective performance of football helmets, motivating new technologies to improve the safety of helmets relative to existing equipment. In this work, we hypothesized that a helmet which transmits a nearly constant minimum force will result in a reduced risk of mTBI. To evaluate the plausibility of this hypothesis, we first show that the optimal force transmitted to the head, in a reduced order model of the brain, is in fact a constant force profile. To simulate the effects of a constant force within a helmet, we conceptualize a fluid-based shock absorber system for use within a football helmet. We integrate this system within a computational helmet model and simulate its performance on the standard NFL helmet test impact conditions. The simulated helmet is compared with other helmet designs with different technologies. Computer simulations of head impacts with liquid shock absorption predict that, at the highest impact speed (9.3 m/s), the average brain tissue strain is reduced by 27.6% ± 9.3 compared to existing helmet padding when tested on the NFL helmet protocol. This simulation-based study puts forth a target benchmark for the future design of physical manifestations of this technology.

An examination of the current National Operating Committee on Standards for Athletic Equipment system and a new pneumatic ram method for evaluating American football helmet performance to reduce risk of concussion

2016 ◽  
Vol 231 (2) ◽  
pp. 83-90 ◽  
Author(s):  
Thomas Blaine Hoshizaki ◽  
Clara Karton ◽  
R. Anna Oeur ◽  
Marshall Kendall ◽  
Lauren Dawson ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Significant Risk ◽  
Standard Test ◽  
American Football ◽  
New Method ◽  
Rotational Acceleration ◽  
Football Helmets ◽  
Athletic Equipment ◽  
New System

Brain injuries are prevalent in the sport of American football. Helmets have been used which effectively have reduced the incidence of traumatic brain injury, but have had a limited effect on concussion rates. In an effort to improve the protective capacity of American football helmets, a standard has been proposed by National Operating Committee on Standards for Athletic Equipment that may better represent helmet-to-helmet impacts common to football concussions. The purpose of this research was to examine the National Operating Committee on Standards for Athletic Equipment standard and a new impact method similar to the proposed National Operating Committee on Standards for Athletic Equipment standard to examine the information these methods provide on helmet performance. Five National Operating Committee on Standards for Athletic Equipment–certified American football helmets were impacted according to the National Operating Committee on Standards for Athletic Equipment standard test and a new method based on the proposed standard test. The results demonstrated that the National Operating Committee on Standards for Athletic Equipment test produced larger linear accelerations than the new method, which were a reflection of the stiffer compliance of the standard meant to replicate traumatic brain injury mechanisms of injury. When the helmets were impacted using a new helmet-to-helmet method, the results reflected significant risk of concussive injury but showed differences in rotational acceleration responses between different helmet models. This suggests that the new system is sensitive enough to detect the effect of different design changes on rotational acceleration, a metric more closely associated with risk of concussion. As only one helmet produced magnitudes of response lower than the National Operating Committee on Standards for Athletic Equipment pass/fail using the new system, and all helmets passed the National Operating Committee on Standards for Athletic Equipment standard, these results suggest that further development of helmet technologies must be undertaken to reduce this risk in the future. Finally, these results show that it would be prudent to use both standards together to address risk of injury from traumatic brain injury and concussion.

Variable area, constant force shock absorption motivated by traumatic brain injury prevention

2020 ◽  
Vol 29 (8) ◽  
pp. 085023
Author(s):  
Michael Fanton ◽  
Hossein Vahid Alizadeh ◽  
August G Domel ◽  
Matthew Devlin ◽  
Mehmet Kurt ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Injury Prevention ◽  
Constant Force ◽  
Shock Absorption

scholarly journals Sport-related concussions

2014 ◽  
Vol 8 (1) ◽  
pp. 14-19 ◽  
Author(s):  
Jéssica Natuline Ianof ◽  
Fabio Rios Freire ◽  
Vanessa Tomé Gonçalves Calado ◽  
Juliana Rhein Lacerda ◽  
Fernanda Coelho ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Behavioral Changes ◽  
American Football ◽  
Health Concern ◽  
Public Health Concern ◽  
Increased Risk ◽  
High Prevalence ◽  
Biomechanical Forces ◽  
The Brain

ABSTRACT Traumatic brain injury (TBI) is a major cause of lifelong disability and death worldwide. Sport-related traumatic brain injury is an important public health concern. The purpose of this review was to highlight the importance of sport-related concussions. Concussion refers to a transient alteration in consciousness induced by external biomechanical forces transmitted directly or indirectly to the brain. It is a common, although most likely underreported, condition. Contact sports such as American football, rugby, soccer, boxing, basketball and hockey are associated with a relatively high prevalence of concussion. Various factors may be associated with a greater risk of sport-related concussion, such as age, sex, sport played, level of sport played and equipment used. Physical complaints (headache, fatigue, dizziness), behavioral changes (depression, anxiety, irritability) and cognitive impairment are very common after a concussion. The risk of premature return to activities includes the prolongation of post-concussive symptoms and increased risk of concussion recurrence.

Experimental and computational investigations of the potential improvement in helmet blast-protection through the use of a polyurea-based external coating

2016 ◽  
Vol 12 (1) ◽  
pp. 33-72 ◽  
Author(s):  
M. Grujicic ◽  
S. Ramaswami ◽  
J. S. Snipes ◽  
R. Yavari ◽  
P. Dudt
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Computational Study ◽  
Element Analysis ◽  
Content Type ◽  
Ballistic Impacts ◽  
Blast Protection ◽  
Protection Efficacy ◽  
Potential Improvement ◽  
External Coating

Purpose – The design of the Advanced Combat Helmet (ACH) currently in use was optimized by its designers in order to attain maximum protection against ballistic impacts (fragments, shrapnel, etc.) and hard-surface/head collisions. Since traumatic brain injury experienced by a significant fraction of the soldiers returning from the recent conflicts is associated with their exposure to blast, the ACH should be redesigned in order to provide the necessary level of protection against blast loads. The paper aims to discuss this issue. Design/methodology/approach – In the present work, an augmentation of the ACH for improved blast protection is considered. This augmentation includes the use of a polyurea (a nano-segregated elastomeric copolymer) based ACH external coating. To demonstrate the efficacy of this approach, blast experiments are carried out on instrumented head-mannequins (without protection, protected using a standard ACH, and protected using an ACH augmented by a polyurea explosive-resistant coating (ERC)). These experimental efforts are complemented with the appropriate combined Eulerian/Lagrangian transient non-linear dynamics computational fluid/solid interaction finite-element analysis. Findings – The results obtained clearly demonstrated that the use of an ERC on an ACH affects (generally in a beneficial way) head-mannequin dynamic loading and kinematic response as quantified by the intracranial pressure, impulse, acceleration and jolt. Originality/value – To the authors’ knowledge, the present work is the first reported combined experimental/computational study of the blast-protection efficacy and the mild traumatic brain-injury mitigation potential of polyurea when used as an external coating on a helmet.

scholarly journals An Overview of the Effectiveness of Bicycle Helmet Designs in Impact Testing

2021 ◽  
Vol 9 ◽  
Author(s):  
Javid Abderezaei ◽  
Fargol Rezayaraghi ◽  
Brigit Kain ◽  
Andrea Menichetti ◽  
Mehmet Kurt
Keyword(s):  
Angular Momentum ◽  
Brain Injury ◽  
Impact Velocity ◽  
New Technologies ◽  
Expanded Polystyrene ◽  
Impact Testing ◽  
Superior Performance ◽  
Bicycle Helmet ◽  
Bicycle Helmets ◽  
The Impact

Cycling accidents are the leading cause of sports-related head injuries in the US. Conventional bicycle helmets typically consist of polycarbonate shell over Expanded Polystyrene (EPS) foam and are tested with drop tests to evaluate a helmet’s ability to reduce head kinematics. Within the last decade, novel helmet technologies have been proposed to mitigate brain injuries during bicycle accidents, which necessitates the evaluation of their effectiveness in impact testing as compared to conventional helmets. In this paper, we reviewed the literature to collect and analyze the kinematic data of drop test experiments carried out on helmets with different technologies. In order to provide a fair comparison across different types of tests, we clustered the datasets with respect to their normal impact velocities, impact angular momentum, and the type of neck apparatus. When we analyzed the data based on impact velocity and angular momentum clusters, we found that the bicycle helmets that used rotation damping based technology, namely MIPS, had significantly lower peak rotational acceleration (PRA) and Generalized Acceleration Model for Brain Injury Threshold (GAMBIT) as compared to the conventional EPS liner helmets (p < 0.01). SPIN helmets had a superior performance in PRA compared to conventional helmets (p < 0.05) in the impact angular momentum clustered group, but not in the impact-velocity clustered comparisons. We also analyzed other recently developed helmets that primarily use collapsible structures in their liners, such as WaveCel and Koroyd. In both of the impact velocity and angular momentum groups, helmets based on the WaveCel technology had significantly lower peak linear acceleration (PLA), PRA, and GAMBIT at low impact velocities as compared to the conventional helmets, respectively (p < 0.05). The protective gear with the airbag technology, namely Hövding, also performed significantly better compared to the conventional helmets in the analyzed kinematic-based injury metrics (p < 0.001), possibly due to its advantage in helmet size and stiffness. We also observed that the differences in the kinematic datasets strongly depend on the type of neck apparatus. Our findings highlight the importance and benefits of developing new technologies and impact testing standards for bicycle helmet designs for better prevention of traumatic brain injury (TBI).

scholarly journals Slow blood-to-brain transport underlies enduring barrier dysfunction in American football players

Brain ◽  
2020 ◽  
Vol 143 (6) ◽  
pp. 1826-1842 ◽  
Author(s):  
Ronel Veksler ◽  
Udi Vazana ◽  
Yonatan Serlin ◽  
Ofer Prager ◽  
Jonathan Ofer ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
White Matter ◽  
Mild Traumatic Brain Injury ◽  
American Football ◽  
Football Players ◽  
Barrier Dysfunction ◽  
Dynamic Contrast Enhanced ◽  
Contrast Enhanced ◽  
Contrast Enhanced Mri

Abstract Repetitive mild traumatic brain injury in American football players has garnered increasing public attention following reports of chronic traumatic encephalopathy, a progressive tauopathy. While the mechanisms underlying repetitive mild traumatic brain injury-induced neurodegeneration are unknown and antemortem diagnostic tests are not available, neuropathology studies suggest a pathogenic role for microvascular injury, specifically blood–brain barrier dysfunction. Thus, our main objective was to demonstrate the effectiveness of a modified dynamic contrast-enhanced MRI approach we have developed to detect impairments in brain microvascular function. To this end, we scanned 42 adult male amateur American football players and a control group comprising 27 athletes practicing a non-contact sport and 26 non-athletes. MRI scans were also performed in 51 patients with brain pathologies involving the blood–brain barrier, namely malignant brain tumours, ischaemic stroke and haemorrhagic traumatic contusion. Based on data from prolonged scans, we generated maps that visualized the permeability value for each brain voxel. Our permeability maps revealed an increase in slow blood-to-brain transport in a subset of amateur American football players, but not in sex- and age-matched controls. The increase in permeability was region specific (white matter, midbrain peduncles, red nucleus, temporal cortex) and correlated with changes in white matter, which were confirmed by diffusion tensor imaging. Additionally, increased permeability persisted for months, as seen in players who were scanned both on- and off-season. Examination of patients with brain pathologies revealed that slow tracer accumulation characterizes areas surrounding the core of injury, which frequently shows fast blood-to-brain transport. Next, we verified our method in two rodent models: rats and mice subjected to repeated mild closed-head impact injury, and rats with vascular injury inflicted by photothrombosis. In both models, slow blood-to-brain transport was observed, which correlated with neuropathological changes. Lastly, computational simulations and direct imaging of the transport of Evans blue-albumin complex in brains of rats subjected to recurrent seizures or focal cerebrovascular injury suggest that increased cellular transport underlies the observed slow blood-to-brain transport. Taken together, our findings suggest dynamic contrast-enhanced-MRI can be used to diagnose specific microvascular pathology after traumatic brain injury and other brain pathologies.

Alteration of Brain Injury Risk by New and Used American Football Helmets

2016 ◽  
Vol 2016.27 (0) ◽  
pp. C206
Author(s):  
Mayuko MITSUI ◽  
Kouta MIYOSHI ◽  
Yuelin ZHANG ◽  
Satoru YONEYAMA ◽  
Hiromichi NAKADATE ◽  
...  
Keyword(s):  
Brain Injury ◽  
Injury Risk ◽  
American Football ◽  
Football Helmets

Consequences of Traumatic Brain Injury in Professional American Football Players

2018 ◽  
Vol 28 (2) ◽  
pp. 91-99 ◽  
Author(s):  
Bodil C. Vos ◽  
Karen Nieuwenhuijsen ◽  
Judith K. Sluiter
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
American Football ◽  
Football Players
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