The Influence of Hard Hat Design Features on Head Acceleration Attenuation

This study evaluated the performance of 6 commercially available hard hat designs—differentiated by shell design, number of suspension points, and suspension tightening system—in regard to their ability to attenuate accelerations during vertical impacts to the head. Tests were conducted with impactor materials of steel, wood, and lead shot (resembling commonly seen materials in a construction site), weighing 1.8 and 3.6 kg and dropped from 1.83 m onto a Hybrid III head/neck assembly. All hard hats appreciably reduced head acceleration to the unprotected condition. However, neither the addition of extra suspension points nor variations in suspension tightening mechanism appreciably influenced performance. Therefore, these results indicate that additional features available in current hard hat designs do not improve protective capacity as related to head acceleration metrics.

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The Electronic Hard Hat: CSCW on the Construction Site

Remote Cooperation: CSCW Issues for Mobile and Teleworkers - Computer Supported Cooperative Work ◽

10.1007/978-1-4471-1496-3_4 ◽

1996 ◽

pp. 23-39

Author(s):

David Madigan

Keyword(s):

Construction Site ◽

Hard Hat

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Development of an Improved Dummy Head for Use in Helmet Certification Tests

10.1115/imece2000-2479 ◽

2000 ◽

Author(s):

Eric H. L. A. van den Bosch ◽

Martijn W. B. M. Leensen ◽

Nancy H. M. Klomp ◽

Fons A. A. H. J. Sauren ◽

Jac S. H. M. Wismans

Keyword(s):

Brain Structure ◽

Evaluation Process ◽

Drop Test ◽

Head Acceleration ◽

First Order ◽

Certification Tests ◽

Hybrid Iii

Abstract First order improvements to the rigid headform, used in current helmet certification tests, are made by introducing a skull and brain structure. In developing the new headform certain requirements were taken into consideration. The new headform appears to meet all requirements but one. The 200 mm drop test with Hybrid-III skin padding on the anvil resulted in too low resultant linear head accelerations. Using a stiffer, more realistic padding on the anvil resulted in a resultant linear head acceleration which satisfies the requirements (100 – 150 g). The padding plays an important role in the evaluation process. Because of the deformable skull, a fairly stiff padding has to be used in order to let the resultant linear head acceleration satisfy the requirements. In contrast to the 200 mm drop test experiments, the padding properties of the skin are of no importance when an EPS padding is placed between the skin and the anvil.

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The Effects of Curtain Airbag on Occupant Kinematics and Injury Index in Rollover Crash

Applied Bionics and Biomechanics ◽

10.1155/2018/4980413 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12

Author(s):

Hongyun Li ◽

Chengyue Jiang ◽

Dong Cui ◽

Shuang Lu

Keyword(s):

Restraint System ◽

Head Acceleration ◽

Physical Test ◽

Injury Index ◽

Hybrid Iii ◽

Protection Area ◽

Occupant Injuries ◽

Occupant Kinematics ◽

Head And Neck Injury ◽

Rollover Crash

Background. Occupant injuries in rollover crashes are associated with vehicle structural performance, as well as the restraint system design. For a better understanding of the occupant kinematics and injury index in certain rollover crash, it is essential to carry out dynamic vehicle rollover simulation with dummy included. Objective. This study focused on effects of curtain airbag (CAB) parameters on occupant kinematics and injury indexes in a rollover crash. Besides, optimized parameters of the CAB were proposed for the purpose of decreasing the occupant injuries in such rollover scenario. Method and Material. The vehicle motion from the physical test was introduced as the input for the numerical simulation, and the 50% Hybrid III dummy model from the MADYMO database was imported into a simulation model. The restraint system, including a validated CAB module, was introduced for occupant kinematics simulation and injury evaluation. TTF setting, maximum inflator pressure, and protection area of the CAB were analysed. Results. After introducing the curtain airbag, the maximum head acceleration was reduced from 91.60 g to 49.52 g, and the neck Mx and neck Fz were reduced significantly. Among these CAB parameters, the TTF setting had the largest effect on the head acceleration which could reduce 8.6 g furthermore after optimization. The neck Fz was decreased from 3766.48 N to 2571.77 N after optimization of CAB protection area. Conclusions. Avoiding hard contact is critical for the occupant protection in the rollover crashes. The simulation results indicated that occupant kinematics and certain injury indexes were improved with the help of CAB in such rollover scenario. Appropriate TTF setting and inflator selection could benefit occupant kinematics and injury indexes. Besides, it was advised to optimize the curtain airbag thickness around the head contact area to improve head and neck injury indexes.

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Validation of a Wireless Head Acceleration Measurement System for Use in Soccer Play

Journal of Applied Biomechanics ◽

10.1123/jab.26.4.424 ◽

2010 ◽

Vol 26 (4) ◽

pp. 424-431 ◽

Cited By ~ 27

Author(s):

Erin Hanlon ◽

Cynthia Bir

Keyword(s):

Measurement System ◽

Cross Correlation ◽

Angular Acceleration ◽

Strong Relationship ◽

Head Acceleration ◽

Acceleration Measurement ◽

Hybrid Iii ◽

Cross Correlations ◽

Rms Error ◽

Soccer Heading

Soccer heading has been studied previously with conflicting results. One major issue is the lack of knowledge regarding what actually occurs biomechanically during soccer heading impacts. The purpose of the current study is to validate a wireless head acceleration measurement system, head impact telemetry system (HITS) that can be used to collect head accelerations during soccer play. The HIT system was fitted to a Hybrid III (HIII) head form that was instrumented with a 3-2-2-2 accelerometer setup. Fifteen impact conditions were tested to simulate impacts commonly experienced during soccer play. Linear and angular acceleration were calculated for both systems and compared. Root mean square (RMS) error and cross correlations were also calculated and compared for both systems. Cross correlation values were very strong withr= .95 ± 0.02 for ball to head forehead impacts andr= .96 ± 0.02 for head to head forehead impacts. The systems showed a strong relationship when comparing RMS error, linear head acceleration, angular head acceleration, and the cross correlation values.

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New test method with a Hybrid III Anthropomorphic Dummy for Textile Safety Harnesses

Fibres and Textiles in Eastern Europe ◽

10.5604/01.3001.0013.5861 ◽

2020 ◽

Vol 28 (1(139)) ◽

pp. 81-86

Author(s):

Krzysztof Baszczyński

Keyword(s):

Test Method ◽

Strength Testing ◽

Head Acceleration ◽

Testing Methods ◽

Testing Method ◽

Experimental Stand ◽

Hybrid Iii ◽

Mechanical Factors ◽

Fall Arrest ◽

Full Body

A full body harness is a basic component of personal fall arrest equipment. It is made from webbing connected by seams and metal fittings to firmly hold and support the user’s body. The paper proposes a new method for full body harness testing using a Hybrid III anthropomorphic dummy; also the design of the experimental stand and software used are described. The method analyses the behaviour of a dummy during a fall arrest under well-defined conditions. The critical mechanical factors measured during the study presented were: the head acceleration, forces acting on the spine, the position of the dummy, the impacts of harness elements to the head, etc. The tests identified some potentially dangerous phenomena associated with falls from a height. The harness testing method developed turned out to be a valuable tool that should be applied in conjunction with existing strength testing methods.

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Laboratory Study of Hybrid-III and THOR Dummy Head/neck Responses to Airbag Load at Close Proximity

10.4271/2004-01-0320 ◽

2004 ◽

Cited By ~ 3

Author(s):

Philemon C. Chan ◽

Zi Lu

Keyword(s):

Laboratory Study ◽

Close Proximity ◽

Hybrid Iii ◽

Head Neck

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Validation of a Noninvasive System for Measuring Head Acceleration for Use during Boxing Competition

Journal of Applied Biomechanics ◽

10.1123/jab.23.3.238 ◽

2007 ◽

Vol 23 (3) ◽

pp. 238-244 ◽

Cited By ~ 45

Author(s):

Jonathan G. Beckwith ◽

Jeffrey J. Chu ◽

Richard M. Greenwald

Keyword(s):

Severity Index ◽

Rotational Acceleration ◽

Head Acceleration ◽

Measuring Head ◽

Head Injury Criterion ◽

Impact Location ◽

Hybrid Iii ◽

Biomechanical Factors ◽

Accuracy And Repeatability ◽

Impact Events

Although the epidemiology and mechanics of concussion in sports have been investigated for many years, the biomechanical factors that contribute to mild traumatic brain injury remain unclear because of the difficulties in measuring impact events in the field. The purpose of this study was to validate an instrumented boxing headgear (IBH) that can be used to measure impact severity and location during play. The instrumented boxing headgear data were processed to determine linear and rotational acceleration at the head center of gravity, impact location, and impact severity metrics, such as the Head Injury Criterion (HIC) and Gadd Severity Index (GSI). The instrumented boxing headgear was fitted to a Hybrid III (HIII) head form and impacted with a weighted pendulum to characterize accuracy and repeatability. Fifty-six impacts over 3 speeds and 5 locations were used to simulate blows most commonly observed in boxing. A high correlation between the HIII and instrumented boxing headgear was established for peak linear and rotational acceleration (r2= 0.91), HIC (r2= 0.88), and GSI (r2= 0.89). Mean location error was 9.7 ± 5.2°. Based on this study, the IBH is a valid system for measuring head acceleration and impact location that can be integrated into training and competition.

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A Six Degree of Freedom Head Acceleration Measurement Device for Use in Football

Journal of Applied Biomechanics ◽

10.1123/jab.27.1.8 ◽

2011 ◽

Vol 27 (1) ◽

pp. 8-14 ◽

Cited By ~ 91

Author(s):

Steven Rowson ◽

Jonathan G. Beckwith ◽

Jeffrey J. Chu ◽

Daniel S. Leonard ◽

Richard M. Greenwald ◽

...

Keyword(s):

Degree Of Freedom ◽

Head Acceleration ◽

Wireless Data ◽

Measurement Device ◽

Football Helmet ◽

Wireless Data Transmission ◽

Hybrid Iii ◽

Football Helmets ◽

High Incidence Rate ◽

Six Degree Of Freedom

The high incidence rate of concussions in football provides a unique opportunity to collect biomechanical data to characterize mild traumatic brain injury. The goal of this study was to validate a six degree of freedom (6DOF) measurement device with 12 single-axis accelerometers that uses a novel algorithm to compute linear and angular head accelerations for each axis of the head. The 6DOF device can be integrated into existing football helmets and is capable of wireless data transmission. A football helmet equipped with the 6DOF device was fitted to a Hybrid III head instrumented with a 9 accelerometer array. The helmet was impacted using a pneumatic linear impactor. Hybrid III head accelerations were compared with that of the 6DOF device. For all impacts, peak Hybrid III head accelerations ranged from 24 g to 176 g and 1,506 rad/s2to 14,431 rad/s2. Average errors for peak linear and angular head acceleration were 1% ± 18% and 3% ± 24%, respectively. The average RMS error of the temporal response for each impact was 12.5 g and 907 rad/s2.

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