Characterization of Fluid-Filled Interconnected Dual-Cells for Reduction of Force and Linear Acceleration due to Blunt Impact

2021 ◽  
Author(s):  
Veysel Erel ◽  
Alexandra Lindsay ◽  
Muthu B. J. Wijesundara ◽  
Inderjeet Singh
Keyword(s):  
Linear Acceleration ◽  
Blunt Impact

Characterization of Fluid-Filled Interconnected Dual-Cells for Reduction of Force and Linear Acceleration due to Blunt Impact

2020 ◽  
Author(s):  
Veysel Erel ◽  
Alexandra R. Lindsay ◽  
Inderjeet Singh ◽  
Muthu B. J. Wijesundara
Keyword(s):  
Reaction Force ◽  
Experimental Studies ◽  
Linear Acceleration ◽  
The United States ◽  
Structure Design ◽  
Impact Behavior ◽  
Negative Effects ◽  
Impact Reduction ◽  
Blunt Impact

Abstract Although modern body and head protective gears are well studied by experts, innovators, and manufacturers, incidence of sports-related injuries is still very high in the United States and all around the world. To reduce the negative effects from blunt impact, an impact reduction structure which contains a channel, shell, and dual-cells was designed and developed with the intention of improving existing helmet liners. This study utilized a previously proven interconnected-cells concept, where a primary cell compresses, then air inside the cell transfers to a secondary cell which expands accordingly, causing impact reduction. While the concept remained the same, a new dual-cells architecture was explored, with numerical and experimental studies for helmet liner impact reduction, and compared to a commercial Xenith helmet liner element. The simulation study began with exploring the effect of adding corrugation to the walls of both cells on impact behavior, then persisted with optimizing impact reduction structure design, and finalized with a comparison study. An experimental study was performed with the optimized structure, provided by simulation, and compared against commercial Xenith helmet liner element in terms of reaction force, linear acceleration, and impact duration. Experimental and simulation results showed that our impact reduction structure provides lower reaction force and linear acceleration.

scholarly journals Evaluation of Combat Helmet Behavior under Blunt Impact

2020 ◽  
Vol 10 (23) ◽  
pp. 8470
Author(s):  
Carlos Moure-Guardiola ◽  
Ignacio Rubio ◽  
Jacobo Antona-Makoshi ◽  
Álvaro Olmedo ◽  
José Antonio Loya ◽  
...  
Keyword(s):  
Brain Injuries ◽  
Linear Acceleration ◽  
Human Head ◽  
Critical Parameters ◽  
Head Model ◽  
Ballistic Impacts ◽  
Impact Surface ◽  
Blunt Impact ◽  
Wide Range ◽  
Design And Manufacture

New threats are a challenge for the design and manufacture of modern combat helmets. These helmets must satisfy a wide range of impact velocities from ballistic impacts to blunt impacts. In this paper, we analyze European Regulation ECE R22.05 using a standard surrogate head and a human head model to evaluate combat helmet performance. Two critical parameters on traumatic brain analysis are studied for different impact locations, i.e., peak linear acceleration value and head injury criterion (HIC). The results obtained are compared with different injury criteria to determine the severity level of damage induced. Furthermore, based on different impact scenarios, analyses of the influence of impact velocity and the geometry impact surface are performed. The results show that the risks associated with a blunt impact can lead to a mild traumatic brain injury at high impact velocities and some impact locations, despite satisfying the different criteria established by the ECE R22.05 standard. The results reveal that the use of a human head for the estimation of brain injuries differs slightly from the results obtained using a surrogate head. Therefore, the current combat helmet configuration must be improved for blunt impacts. Further standards should take this into account and, consequently, combat helmet manufacturers on their design process.

Characterization of On-Field Head Impact Exposure in Youth Soccer

2020 ◽  
pp. 1-7
Author(s):  
Brian T. Tomblin ◽  
N. Stewart Pritchard ◽  
Tanner M. Filben ◽  
Logan E. Miller ◽  
Christopher M. Miles ◽  
...  
Keyword(s):  
Linear Acceleration ◽  
Head Impact ◽  
Video Data ◽  
Soccer Players ◽  
Youth Soccer ◽  
Head Impacts ◽  
Head Kinematics ◽  
Frequency Of Contact ◽  
Ball Contact

The objective of this research was to characterize head impacts with a validated mouthpiece sensor in competitive youth female soccer players during a single season with a validated mouthpiece sensor. Participants included 14 youth female soccer athletes across 2 club-level teams at different age levels (team 1, ages 12–13 y; team 2, ages 14–15 y). Head impact and time-synchronized video data were collected for 66 practices and games. Video data were reviewed to characterize the type and frequency of contact experienced by each athlete. A total of 2216 contact scenarios were observed; heading the ball (n = 681, 30.7%) was most common. Other observed contact scenarios included collisions, dives, falls, and unintentional ball contact. Team 1 experienced a higher rate of headers per player per hour of play than team 2, while team 2 experienced a higher rate of collisions and dives. A total of 935 video-verified contact scenarios were concurrent with recorded head kinematics. While headers resulted in a maximum linear acceleration of 56.1g, the less frequent head-to-head collisions (n = 6) resulted in a maximum of 113.5g. The results of this study improve the understanding of head impact exposure in youth female soccer players and inform head impact exposure reduction in youth soccer.

Evaluation of the Kinematic Biofidelity and Inter-Test Repeatability of Global Accelerations and Brain Parenchyma Pressure for a Head-Brain Physical Model

2021 ◽  
Author(s):  
Yizhao Li ◽  
Simon Ouellet ◽  
Albert Vette ◽  
Don W. Raboud ◽  
Ashton Martin ◽  
...  
Keyword(s):  
Linear Acceleration ◽  
Brain Parenchyma ◽  
Head Model ◽  
Civilian Life ◽  
Head Kinematics ◽  
Blunt Impact ◽  
Hybrid Iii ◽  
Drop Tests ◽  
Multiple Impact ◽  
Injury Protection

Abstract Head surrogates are used in biomechanical research and headgear assessment. They are designed to approximate the properties of the head and are instrumented to measure global head kinematics. Due to the recent interest in studying disruption to the brain, some head models include internal fluid layers and brain tissue, and instrumentation to measure head intracranial biomechanics. However, it is unknown whether such models exhibit realistic human responses. Therefore, this study aims to assess the biofidelity and repeatability of a head model, the Blast Injury Protection Evaluation Device (BIPED), that can measure both global head kinematics and intraparenchymal pressure (IPP) for application in blunt impact, a common loading scenario in civilian life. Drop tests were conducted with the BIPED and the widely used Hybrid III headform. BIPED measures were compared to the Hybrid III data and published cadaveric data, and the biofidelity level of the global linear acceleration was quantified using CORrelation and Analysis (CORA) ratings. The repeatability of the acceleration and IPP measurements in multiple impact scenarios was evaluated via the coefficient of variation (COV) of the magnitudes and pulse durations. BIPED acceleration peaks were generally not significantly different from cadaver and Hybrid III data. The CORA ratings for the BIPED and Hybrid III accelerations ranged from 0.50 to 0.61 and 0.51 to 0.77, respectively. The COVs of acceleration and IPP were generally below 10%. This study is an important step toward a biofidelic head surrogate measuring both global kinematics and IPP in blunt impact.

Experimental Determination of Pressure Wave Transmission to the Brain During Head-Neck Blast Tests

2013 ◽  
Author(s):  
Kyle Ott ◽  
Liming Voo ◽  
Andrew Merkle ◽  
Alexander Iwaskiw ◽  
Alexis Wickwire ◽  
...  
Keyword(s):  
Brain Injury ◽  
Brain Injuries ◽  
Head Injuries ◽  
Strong Association ◽  
Skull Fracture ◽  
Linear Acceleration ◽  
Military Operations ◽  
Blunt Impact ◽  
Injury Mechanisms ◽  
Inertial Loading

Traumatic Brain Injury (TBI) has been the termed the “signature injury” in wounded soldiers in recent military operations [1]. Evidence has shown a strong association between TBI and blast loading to the head due to exposure to explosive events [2, 3]. Head injury mechanisms in a primary blast environment remain elusive and are the subject of much speculation and hypotheses. However, brain injury mechanisms have traditionally been attributed to either a direct impact or a rapid head acceleration or deceleration. Extensive research has been performed regarding the effects of blunt trauma and inertial loading on head injuries [4, 5]. Direct impacts to the head can largely be described based on linear acceleration measurements that correlate to skull fracture and focal brain injuries [6]. Computational head modeling of blunt impact events has shown that the linear acceleration response correlates well with increases in brain pressure [7]. Intracranial pressure, therefore, has been one of the major quantities investigated for correlation to blast induced TBI injury mechanisms [8–14].

Combat helmet liner design for blunt impact absorption using multi-output Gaussian process surrogates

2020 ◽  
pp. 095440622096076 ◽  
Author(s):  
George J Barlow ◽  
Christopher Page ◽  
Patrick Drane ◽  
Scott E Stapleton ◽  
Benjamin Fasel ◽  
...  
Keyword(s):  
Gaussian Process ◽  
Impact Velocity ◽  
Linear Acceleration ◽  
Design Parameters ◽  
Test Results ◽  
Design Metrics ◽  
Impact Performance ◽  
Blunt Impact ◽  
Testing Standards ◽  
First Time

A finite element based computational model simulating the standard drop tower test for military helmets was created and used in conjunction with a multi-output Gaussian process surrogate to seek different designs of helmets for improved blunt impact performance. Experimental drop test results were used for the validation of the model’s ability to simulate impact. The influence of foam stiffness, impact velocity, strap tension, as well as pad placement and size on parameters on the peak linear acceleration (PLA) of the headform was investigated for the first time through a surrogate model trained by strategically choosing simulation points. Impact velocity was found to have the greatest effect. The strap tension and foam pad stiffness ranges examined within this sampling plan were found to have less of an effect on the performance of the helmet than the pad size and shape parameters examined. The surrogate modeling approach was used to quantify the influence of design parameters and can lead to not only improved helmet designs but also new data-driven design metrics and testing standards to accelerate the development of TBI-mitigating helmets.

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

Characterization of Coherent, Ordered Precipitates in Nickel-Base Alloys

1973 ◽  
Vol 31 ◽  
pp. 144-145
Author(s):  
B. H. Kear ◽  
J. M. Oblak
Keyword(s):  
Stable Phase ◽  
Nickel Base Superalloy ◽  
Alloy 718 ◽  
Commercial Alloy ◽  
Precipitate Morphology ◽  
Continuous Precipitation ◽  
Nickel Base ◽  
Base Superalloy ◽  
Strengthening Precipitate

A nickel-base superalloy is essentially a Ni/Cr solid solution hardened by additions of Al (Ti, Nb, etc.) to precipitate a coherent, ordered phase. In most commercial alloy systems, e.g. B-1900, IN-100 and Mar-M200, the stable precipitate is Ni3 (Al,Ti) γ′, with an LI2structure. In A lloy 901 the normal precipitate is metastable Nis Ti3 γ′ ; the stable phase is a hexagonal Do2 4 structure. In Alloy 718 the strengthening precipitate is metastable γ″, which has a body-centered tetragonal D022 structure.Precipitate MorphologyIn most systems the ordered γ′ phase forms by a continuous precipitation re-action, which gives rise to a uniform intragranular dispersion of precipitate particles. For zero γ/γ′ misfit, the γ′ precipitates assume a spheroidal.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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