Motorcycle Helmet Part I. Biomechanics and Computational Issues.
TL;DR: In this article, the current status related to motorcycle helmet crash studies from biomechanics and computational point of view is reviewed, and the importance of motorcycle helmet performance on statistical background was reviewed.
About: This article is published in Journal of Materials Processing Technology.The article was published on 2002-05-10. It has received 52 citations till now.
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TL;DR: In a non-restrictive, and never up-to-date report, a state-of-art review on road helmets safety is done, with a special insight into brain injury, helmet design and standards.
106 citations
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TL;DR: In this article, the feasibility of using a hierarchical lattice liners for helmets was studied and the results show that using such liners has the potential of significantly reducing the risk of head injury compared to a helmet with traditional EPS liners and could potentially be considered as the new generation of energy absorbing liners.
Abstract: Helmets are the most important piece of protective equipment for motorcyclists. The liner of the helmet is the main part of the helmet which dissipates the impact energy and mitigates the load transmitted to the head. Therefore, optimizing the material that absorbs most of the impact energy would improve the helmet’s protection capacity. It is known that the energy absorption of the helmet liner can be optimized by means of using liners with varying properties through the thickness, however currently the majority of used liners exhibit constant properties through the thickness. Advances in the field of topology optimization and additive manufacturing provide the ability of building complex geometries and tailoring mechanical properties. Along those lines, in the present work the feasibility of using a hierarchical lattice liner for helmets was studied. Finite element method was employed to study whether a hierarchical lattice liner could reduce the risk of head injuries in comparison to currently used liner materials. The results show that using a hierarchical lattice liner has the potential of significantly reducing the risk of head injury compared to a helmet with traditional EPS liner and could potentially be considered as the new generation of energy absorbing liners for helmets.
47 citations
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TL;DR: In this paper, a simulation-based method was proposed to study the rear effect by using Head Injury Criterion (HIC) when the ballistic helmeted headform is impacted by a bullet with different impact angles and at various impact positions.
Abstract: Ballistic impact is one of the major causes for traumatic brain injury (TBI) and ballistic helmets are designed to provide protection from TBI. In real life, it is impossible to use real human subjects for experiments. Therefore, simulation based-methods are convenient to assess the rear effect to ballistic helmet impact and can provide crucial insights to injury. Rear effect happens when the interior of helmet is deformed and contacts with the human head. This paper proposes a simulation-based method to study the rear effect by using Head Injury Criterion (HIC) when the ballistic helmeted headform is impacted by a bullet with different impact angles and at various impact positions. Commercial software package LS-DYNA is employed to simulate the impact. A high fidelity headform model including detailed skull and brain has been used for the simulation purpose. Helmet and bullet are modeled according to the real shapes. The results show that, with a larger impact angle, the HIC score is smaller and ...
46 citations
Cites background from "Motorcycle Helmet Part I. Biomechan..."
...Significant research work has been done on numerical simulations of mainly motorcycle helmets [25], [14], [22], [18....
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TL;DR: In this article, the authors studied the influence of the presence of the body on the impact response of the helmeted head and found that increased body mass has the same influence on impact outputs as including the whole body in impact tests.
Abstract: The most frequent type of injury that causes death or disability in motorcycle accidents is head injury. The only item of personal protective equipment that protects a motorcyclist's head in real-world accidents is the safety helmet. The protective capability of a helmet is assessed, according to international standards, through the impact of a headform fitted with the helmet onto an anvil. The purpose of the present work was to study the influence of the presence of the body on the impact response of the helmeted head. Full-body and detached-head impacts were simulated using the finite element (FE) method. As a consequence of the presence of the body, the crushing distance of the helmet liner was drastically increased. This evidence indicated that the effect of the body should be included in impact absorption tests in order to provide conditions that are more realistic and stringent. The solution to an analytical model of the helmeted headform impact revealed that increasing the headform mass has the same influence on impact outputs, particularly the liner's crushing distance, as including the whole body in impact tests. The added mass was calculated by using a helmeted Hybrid III dummy for an impact configuration that frequently occurred in real-world accidents.
42 citations
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03 Aug 2015TL;DR: This review paper gives a thorough overview of the work carried out by the scientific community in the field of impact biomechanics about head injuries sustained during sports activity and presents the head injury criteria and their respective thresholds.
Abstract: Head injuries occur in a great variety of sports. Many of these have been associated with neurological injuries, affecting the central nervous system. Some examples are motorsports, cycling, skiing, horse riding, mountaineering and most contact sports such as football, ice and field hockey, soccer, lacrosse, etc. The outcome of head impacts in these sports can be very severe. The worst-case scenarios of permanent disability or even death are possibilities. Over recent decades, many In recent decades, a great number of head injury criteria and respective thresholds have been proposed. However, the available information is much dispersed and a consensus has still not been achieved regarding the best injury criteria or even their thresholds. This review paper gives a thorough overview of the work carried out by the scientific community in the field of impact biomechanics about head injuries sustained during sports activity. The main goal is to review the head injury criteria, as well as their thresholds. Several are reviewed, from the predictors based on kinematics to the ones based on human tissue thresholds. In this work, we start to briefly introduce the head injuries and their mechanisms commonly seen as a result of head trauma in sports. Then, we present and summarize the head injury criteria and their respective thresholds.
42 citations
References
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TL;DR: The purpose of this paper is to present results from methodologies used in the laboratory that are targeted toward identifying specific brain injury thresholds, as well as identifying new means of diagnostic and treatment techniques for diffuse axonal injury.
Abstract: The purpose of this paper is to present results from methodologies used in our laboratory that are targeted toward identifying specific brain injury thresholds. Results from studying one form of brain injury, diffuse axonal injury, are presented in this report. Physical models, or surrogates, of the skull-brain complex are used to estimate the relationship between inertial loading and brain deformation. A porcine model of diffuse axonal injury, developed with information from these physical models and earlier in vitro tissue modeling studies, is used to correlate histologic and radiologic evidence of axonal injury to predicted regions of injury from the experimental and theoretical analysis. These results form the basis for developing improved diffuse brain injury tolerance levels, as well as identifying new means of diagnostic and treatment techniques for diffuse axonal injury.
246 citations
01 Jan 1980
TL;DR: In this paper, an on-scene, in-depth investigation of 900 motorcycle accidents was conducted in Los Angeles, California, where human factors, vehicle and environmental data were collected.
Abstract: An on-scene, in-depth investigation of 900 motorcycle accidents was conducted in Los Angeles, California. Crash tests were conducted to train the research team in accident reconstruction. The accident investigators, who were both motorcyclists and scientists, collected human factors, vehicle and environmental data. Motorcycle rider error was found to be the principal causative factor in 40% of the cases, and violation of the cyclist's right of way in 50% of the accidents. Intersections were found to be particularly dangerous, and motorcycle conspicuity a major problem. In 77% of the multiple vehicle collisions, cars came from the 11:00, 12:00, or 1:00 o'clock position, and the car turning left in front of the oncoming motorcycle was the typical critical accident configuration. Use of headlights is very effective in reducing these types of accidents, as well as the wearing of high-visibility upper torso garments. Equipment such as face shields or goggles are warranted, mainly to aid driver vision. The median pre-crash speed for the involved motorcycles was 30 mph. Most accident-involved cyclists have had no formal training and lack collision-avoidance skills (with braking a particular problem). Helmets are critical in preventing head injuries. Included is a question-and-answer session which followed a film presentation on helmet effectiveness.
244 citations
01 Jan 1981
TL;DR: In this article, the authors present the data and findings from the on-scene, in-depth investigations of 900 motorcycle accidents and the analysis of 3600 motorcycle traffic accident reports in the same study area.
Abstract: The report presents the data and findings from the on-scene, in-depth investigations of 900 motorcycle accidents and the analysis of 3600 motorcycle traffic accident reports in the same study area. Volume II is the Appendix with terminology, field data forms, and supplemental data and analysis.
171 citations
01 Jan 1990
TL;DR: In this article, the dynamic response of the human head to side impact was studied by 2-dimensional finite element modeling, and three models were formulated in this study: an axisymmetric model, a single-layered spherical shell filled with an inviscid fluid, and a plane strain model of a coronal section of the head.
Abstract: The dynamic response of the human head to side impact was studied by 2-dimensional finite element modeling. Three models were formulated in this study. Model I is an axisymmetric model. It simulated closed shell impact of the human head, and consisted of a single-layered spherical shell filled wiht an inviscid fluid. The other two models (Model II and III) are plane strain models of a coronal section of the human head. Model II approximated a 50th percentile male head by an outer layer to simulate cranial bone and an inviscid interior core to simulate the intracranial contents. The configuration of Model III is the same as Model II but more detailed anatomical features of the head interior were added, such as, cerebral spinal fluid (CSF); falx cerebri, dura, and tentorium. Linear elastic material properties were assigned to all three models. All three models were loaded by a triangular pulse with a peak pressure of 40 kPa, effectively producing a peak force of 1954 N (440 lb). The purpose of this study was to determine the effects of the membranes and that of the mechanical properties of the skull, brain, and membrane on the dynamic response of the brain during side impact, and to compare the pressure distributions from the plane strain model with the axisymmetric model. A parametric study was conducted on Model II to characterize fully its response to impact under various conditions.(ABSTRACT TRUNCATED AT 250 WORDS)
163 citations
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TL;DR: The purpose of this study was to determine the effects of the membranes and that of the mechanical properties of the skull, brain, and membrane on the dynamic response of the brain during side impact, and to compare the pressure distributions from the plane strain model with the axisymmetric model.
Abstract: The dynamic response of the human head to side impact was studied by 2-dimensional finite element modeling. Three models were formulated in this study. Model I is an axisymmetric model. It simulated closed shell impact of the human head, and consisted of a single-layered spherical shell filled wiht an inviscid fluid. The other two models (Model II and III) are plane strain models of a coronal section of the human head. Model II approximated a 50th percentile male head by an outer layer to simulate cranial bone and an inviscid interior core to simulate the intracranial contents. The configuration of Model III is the same as Model II but more detailed anatomical features of the head interior were added, such as, cerebral spinal fluid (CSF); falx cerebri, dura, and tentorium. Linear elastic material properties were assigned to all three models. All three models were loaded by a triangular pulse with a peak pressure of 40 kPa, effectively producing a peak force of 1954 N (440 lb). The purpose of this study was to determine the effects of the membranes and that of the mechanical properties of the skull, brain, and membrane on the dynamic response of the brain during side impact, and to compare the pressure distributions from the plane strain model with the axisymmetric model. A parametric study was conducted on Model II to characterize fully its response to impact under various conditions.(ABSTRACT TRUNCATED AT 250 WORDS)
156 citations