Finite element analysis of the effectiveness of bicycle helmets in head impacts against roads

Oikawa, Shoko; Nakadate, Hiromichi; Zhang, Yuelin; Ueno, Takahiro; Aomura, Shigeru; Matsui, Yasuhiro

doi:10.1299/jbse.17-00175

Cited by 3 publications

(4 citation statements)

References 29 publications

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“…The effectiveness of helmet use policy for motorcycle users was positively found in Taiwan (Chang, 2005) and Iran (Bazargani et al, 2017). Although the ratio of it was very low in Japan, bicycle helmet use considerably could decrease the risk of head injuries (Oikawa et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

Epidemiological Study of Road Traffic Accidents in Japan during 2010-2019

Khuluqi¹,

Kurniawidjaja²

2021

jmhs

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The study aimed to determine epidemiological characteristics of road traffic accidents in Japan during the year 2010-2019. A cross-sectional descriptive study depended on a retrospective analysis of road traffic accident data that were obtained from the National Police Agency (NPA) for the years 2010 – 2019 in Japan. The relationship of road traffic accident consequences as dependent variables with age, road user type, helmet, and seatbelt use as independent variables during the studied years was analyzed with Chi-square test. The case fatality rate has been declining every year from 3.88 in 2010 to 2.54 per 100,000 persons. More than half of fatality cases have occurred among the elderly. There was a statistically significant relationship between road user type and accident severities. 36.21% fatality occurred in pedestrians. Otherwise, 27.61% of motor vehicle occupants were dominant in serious injury cases and 66.87% in slight injury cases. Most of the casualties revealed for fatality cases were in the head, whereas the leg part was dominant in serious injury cases and the neck region was raised in slight injuries. There was a significant relationship between the use of helmets and seat belt use with casualties of road traffic accidents. There was a declined trend of road traffic accidents in Japan during 10 years of study. The result of the epidemiological study could be a valid consideration for the design of road safety policy in the future.

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Section: Discussionmentioning

confidence: 99%

Epidemiological Study of Road Traffic Accidents in Japan during 2010-2019

Khuluqi¹,

Kurniawidjaja²

2021

jmhs

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“…The regions used in the original text were defined as: frontal (27%), lateral (56%), vertex (13%) and occipital (4%). Oikawa et al 81 Damage to 134 cycle helmets from Japan were categorised (crack/break/ deformation / abrasion) Frontal and lateral regions of helmets are most frequently damaged (location data based on paper by Omada and Konosu. 86 Note that the raw data was unavailable and there was no translation available for the paper (which is written in Japanese) therefore this study was excluded from the meta-analysis 86 …”

Section: Appendixmentioning

confidence: 99%

A Review of Cyclist Head Injury, Impact Characteristics and the Implications for Helmet Assessment Methods

Baker

Patel

et al. 2023

Ann Biomed Eng

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Head injuries are common for cyclists involved in collisions. Such collision scenarios result in a range of injuries, with different head impact speeds, angles, locations, or surfaces. A clear understanding of these collision characteristics is vital to design high fidelity test methods for evaluating the performance of helmets. We review literature detailing real-world cyclist collision scenarios and report on these key characteristics. Our review shows that helmeted cyclists have a considerable reduction in skull fracture and focal brain pathologies compared to non-helmeted cyclists, as well as a reduction in all brain pathologies. The considerable reduction in focal head pathologies is likely to be due to helmet standards mandating thresholds of linear acceleration. The less considerable reduction in diffuse brain injuries is likely to be due to the lack of monitoring head rotation in test methods. We performed a novel meta-analysis of the location of 1809 head impacts from ten studies. Most studies showed that the side and front regions are frequently impacted, with one large, contemporary study highlighting a high proportion of occipital impacts. Helmets frequently had impact locations low down near the rim line. The face is not well protected by most conventional bicycle helmets. Several papers determine head impact speed and angle from in-depth reconstructions and computer simulations. They report head impact speeds from 5 to 16 m/s, with a concentration around 5 to 8 m/s and higher speeds when there was another vehicle involved in the collision. Reported angles range from 10° to 80° to the normal, and are concentrated around 30°–50°. Our review also shows that in nearly 80% of the cases, the head impact is reported to be against a flat surface. This review highlights current gaps in data, and calls for more research and data to better inform improvements in testing methods of standards and rating schemes and raise helmet safety.

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“…The FE simulation used FE models of the human head (Aomura et al, 2016), the bicycle helmet (Oikawa et al, 2017), and the wall using the LS-DYNA (version 8.0) commercial FE software (LSTC, 2015). The FE model of the human head, developed by Aomura et al in 2016, consisted of the main anatomical features, including the scalp, skull, cerebrospinal fluid, cerebrum, corpus callosum, ventricle, cerebellum, brain stem, falx, and tentorium.…”

Section: Simulation Using An Fe Model Of the Human Head And An Fe Bicmentioning

confidence: 99%

“…The FE bicycle helmet model (Oikawa et al, 2017) was developed based on the FIGO G-1 commercial bicycle helmet for an adult male (OGK Kabuto, 2012). The model consisted of a polycarbonate outer shell and a polystyrene form liner (Milne et al, 2013), components of the FIGO G-1 helmet.…”

Section: Simulation Using An Fe Model Of the Human Head And An Fe Bicmentioning

confidence: 99%

Correlation between acute phase head injury to cyclists and consciousness disturbance: a case study in reconstruction of single-cyclist accident

Oikawa

Matsui

Gomei

et al. 2019

JBSE

Self Cite

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This study first examined the correlation between types of acute phase head injuries to cyclists and consciousness disturbance by using data from patients at the emergency room of Dokkyo Medical University Koshigaya Hospital in Japan. The injuries were compared for cases where the cyclists experienced consciousness disturbance and otherwise. The results showed that skull fractures and brain contusions were the most frequent consequences of head injuries to cyclists in general. However, the average number of head injuries by types for cyclists suffering consciousness disturbance was higher than that for cyclists who had not experienced it, for both head fractures (0.9 versus 0.7) and brain injuries (1.9 versus 0.5). This implies that head fractures and brain injuries may increase the probability of consciousness disturbance. Next, considering a cyclist who had sustained a head injury and suffered acute consciousness disturbance in an accident while not wearing a helmet, a case study was conducted to quantify the effectiveness of a bicycle helmet in reducing the intensity of traumatic head injuries by using a whole-body model, a finite element model of the human head, and a model of the bicycle helmet on a mathematical dynamic modeling software. A comparison of the peak values computed for cases of cyclists with and without a helmet showed that in the former, strain on the skull was reduced by 95.9% in cases of skull fractures, and the von Mises stress on the brain was reduced by 23.3% for cases of brain contusions. The results suggest that helmet use reduces the risk of skull fracture and brain contusions in cyclists because it considerably reduces the impact. Moreover, the use of helmets can reduce the probability of consciousness disturbance.

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Finite element analysis of the effectiveness of bicycle helmets in head impacts against roads

Cited by 3 publications

References 29 publications

Epidemiological Study of Road Traffic Accidents in Japan during 2010-2019

Epidemiological Study of Road Traffic Accidents in Japan during 2010-2019

A Review of Cyclist Head Injury, Impact Characteristics and the Implications for Helmet Assessment Methods

Correlation between acute phase head injury to cyclists and consciousness disturbance: a case study in reconstruction of single-cyclist accident

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