The Dynamic Impact Response of a Hybrid III Head- and Neckform Under Four Neck Orientations and Three Impact Locations PDF Download
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Author: Scott G. Foreman
Publisher:
ISBN:
Category : Biomechanics
Languages : en
Pages : 108
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Book Description
Author: Scott G. Foreman
Publisher:
ISBN:
Category : Biomechanics
Languages : en
Pages : 108
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Book Description
Author: Marshall Kendall
Publisher:
ISBN:
Category : Biofidelic
Languages : en
Pages : 11
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Book Description
The development of surrogate headforms with similar dimensions and weight to that of a human head has allowed researchers to collect dynamic impact response data for impact reconstructions and injury assessment. These headforms are relied upon to deliver accurate and repeatable dynamic impact response data for setting helmet certification standards as well as head injury reconstruction. With recent research demonstrating the importance of measuring three dimensional dynamic impact response characteristics, the Hybrid III headform is a potentially a good candidate for use in standards testing and impact reconstructions. Currently, this headform is validated with a single 37.6-cm drop to the front region of the headform with an acceptance window of 50 g. Therefore, the purpose of this study was to compare the dynamic impact response of two Hybrid III headforms and verify repeatability, compare dynamic impact response, and determine how closely the two headforms correlate across different impact conditions. Two Hybrid III headforms were dropped from nine heights at two impact locations (front and side). Results of this study show that the two headforms are highly correlated across drop heights. Significant differences in terms of dynamic impact response were found between the two headforms across impact conditions. This study showed that two Hybrid III headforms produce similar mean peak linear acceleration for front centric impacts, however, differ significantly for mean peak angular response.
Author: Philippe Rousseau
Publisher:
ISBN:
Category : Biomechanics
Languages : en
Pages : 150
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Author: Anna Oeur
Publisher:
ISBN:
Category : Angles (Geometry)
Languages : en
Pages :
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The objective of this research was to better understand how impact angle influences headform dynamic response and brain tissue deformation. A bare headform was impacted using a pneumatic linear impactor at 5.5 m/s. The impacts were directed on the front and side location at angles of 0, 5, 10 and 15° rightward rotations as well as -5, -10 and -15° (leftward) rotations at the side to examine the characteristics of the head and neckform on the results. Peak resultant linear and rotational accelerations from the headform as well as peak maximum principal strain (MPS) and von Mises stress (VMS) estimated from a brain finite element model were used to measure the effect of impact angle. Significant results were dependent upon the impact angle and location as well as the dependent variable used for comparison (p
Author: Natalie R. Coulson
Publisher:
ISBN:
Category : Biomechanics
Languages : en
Pages : 206
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Author: Clara Karton
Publisher:
ISBN:
Category : Biomechanics
Languages : en
Pages :
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Book Description
The varied impact parameters that characterize an impact to the head have shown to influence the resulting type and severity of outcome injury, both in terms of the dynamic response, and the corresponding deformation of neural tissue. Therefore, when determining head injury risks through event reconstruction, it is important to understand how individual impact characteristics influence these responses. The effect of inbound mass had not yet been documented in the literature. The purpose of this study was to determine the effects of inbound mass on the dynamic impact response and brain tissue deformation. A 50th percentile Hybrid III adult male head form was impacted using a simple pendulum system. Impacts to a centric and a non-centric impact location were performed with six varied inbound masses at a velocity of 4.0 m/s. The peak linear and peak angular accelerations were measured. A finite element model, (UCDBTM) was used to determine brain deformation, namely peak maximum principal strain and peak von Mises stress. Inbound mass produced significant differences for peak linear acceleration for centric (F(5, 24) = 217.55, p=.0005) and non-centric (F(5, 24) = 161.98, p=.0005), and for peak angular acceleration for centric (F(5, 24) = 52.51, p=.0005) and non-centric (F(5, 24) = 4.18, p=.007) impact locations. A change in inbound mass also had a significant effect on peak maximum principal strain for centric (F(5, 24) = 11.04, p=.0005) and non-centric (F(5, 24) = 5.87, p =.001), and for peak von Mises stress for centric (F(5, 24) = 24.01, p=.0005) and non-centric (F(5, 24) = 4.62, p=.004) impact locations. These results indicate the inbound mass of an impact should be of consideration when determining risks and prevention to head and brain injury.
Author: Marjorie. R. Seemann
Publisher:
ISBN:
Category : Automobiles
Languages : en
Pages : 21
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Book Description
ABSTRACT -- In this paper human volunteer head/neck dynamic response is compared with that of a Hybrid III head and neck. The data base used for the comparison was taken from the extensive Naval Biodynamics Laboratory data base of human volunteers and manikin sled runs for various thrust vector directions.
Author: Gabriella Faith Wynn
Publisher:
ISBN:
Category : Head
Languages : en
Pages : 0
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Book Description
Head impacts, both concussive and sub-concussive, are common in sports and can lead to adverse side effects. Since head kinematics are thought to correlate with brain injury, the implementation of protective headgear aimed to mitigate kinematics of the head during impacts. While fatal brain injuries have been reduced, concussions and other long-term effects of repetitive head impacts are still prevalent in football players at all levels. Physical surrogate models of the human head and neck are often used to assess impact severity in sports and infer the risk of brain injury, and in helmet certifications to explore the efficacy of helmets. The surrogate models can be instrumented with accelerometers to measure resultant head kinematics. Since the neck is thought to partially govern head kinematics during impact, the surrogate necks must demonstrate several performance characteristics to produce accurate results. Commercially available necks have acceptable repeatability and reproducibility, but they were not developed for the direct, multiplane loading in sports. As such, a novel prototype surrogate neck was developed for omni-directional direct head impacts. The objective of this work was to assess the repeatability and reproducibility of the neck. Three copies of the prototype surrogate neck and one Hybrid III neck were attached to the same Hybrid III head and repeatedly impacted at 3.5 m/s using a pendulum impactor. Both the helmeted and the unhelmeted head were impacted at the front and the front boss locations. The within-neck coefficient of variation (CVW) of the prototype surrogate neck kinematics for all impact conditions was 10% or less, which satisfies standard requirements for surrogates and is comparable to work on several standardized surrogate models. While differences between the three prototype surrogate necks were generally statistically significant, the normalized absolute differences between the neck copies were usually less than 10% and less than 20% in all cases except one. Most head and neck certifications for current standardized models provide corridors that allow a range of ±10% on mean peak kinematics to be considered within specification - the normalized absolute differences of the prototype surrogate neck kinematics fall within that range. Further, the normalized absolute differences for other neck models were similar to what was calculated for the prototype surrogate neck. The reproducibility coefficient of variation (CVB) values for the prototype surrogate necks were less than 15% for all kinematics and usually 10% or less, which is considered acceptable and is comparable to the reproducibility of commercially available surrogate models. The prototype surrogate neck had CVW values equivalent to the Hybrid III, but definitive conclusions cannot be made as to whether the kinematics differ. The Hybrid III kinematics were significantly different from the prototype surrogate neck kinematics for unprotected impacts, and the normalized absolute differences were greater than the differences calculated between the three copies of the prototype surrogate neck. In contrast, the helmeted impacts resulted in kinematics that were less significantly different between the Hybrid III and the prototype surrogate neck, with the normalized absolute differences commensurate in magnitude for the Hybrid III comparison and the prototype surrogate neck reproducibility assessment. However, the Hybrid III neck almost always had kinematics consistently greater than or less than all three of the prototype surrogate necks. Thus, the signs on the kinematics allow observation of actual differences between necks. In summary, the prototype surrogate neck fit to a Hybrid III head and subject to multi-directional direct head impacts resulted in repeatable and reproducible kinematics. Although more testing is needed to quantify differences between the prototype surrogate neck and the Hybrid III, the prototype surrogate neck may be an effective tool for sports impact assessments.
Author: W. King
Publisher: Springer Science & Business Media
ISBN: 1475715021
Category : Technology & Engineering
Languages : en
Pages : 401
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Author: Channing L. Ewing
Publisher:
ISBN:
Category : Acceleration (Physiology)
Languages : en
Pages : 28
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Book Description
A study is underway to determine the dynamic response of the head and neck of living human subjects to -Gx impact acceleration, using transducers to measure differential displacements and differential angular and linear accelerations of the head with reference to the base of the neck in response to the input acceleration measured at that point. A redundant photographic data system is being used for validation. Preliminary results are presented.
