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Investigation on an Injury Criterion Related to Traumatic Brain Injury Primarily Induced by Head Rotation

Honda R&D Co., Ltd.-Toshiyuki Yanaoka, Yasuhiro Dokko, Yukou Takahashi
Published 2015-04-14 by SAE International in United States
The high frequency of fatal head injuries is one of the important issues in traffic safety, and Traumatic Brain Injuries (TBIs) without skull fracture account for approximately half of them in both occupant and pedestrian crashes. In order to evaluate vehicle safety performance for TBIs in these crashes using anthropomorphic test dummies (ATDs), a comprehensive injury criterion calculated from the rotational rigid motion of the head is required. While many studies have been conducted to investigate such an injury criterion with a focus on diffuse brain injuries in occupant crashes, there have been only a limited number of studies focusing on pedestrian impacts. The objective of this study is to develop a comprehensive injury criterion based on the rotational rigid body motion of the head suitable for both occupant and pedestrian crashes.In this study, an injury criterion that correlates with the tissue-level predictors of diffuse brain injuries in both occupant and pedestrian crashes is proposed by incorporating the change of the rotational velocity during a certain maximum time. A mid-sized male human head/brain FE model…
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Investigation on Generational Difference of Intracranial Responses Related to Traumatic Brain Injuries Using Age-Specific Human Head/Brain FE Models

Honda R&D Co., Ltd.-Toshiyuki Yanaoka, Yasuhiro Dokko
Published 2014-04-01 by SAE International in United States
The high frequency of fatal head injuries of elderly people in traffic accidents is one of the important issues in Japan. One of the causes may be vulnerability of the aged brain. While a human head/brain FE model is a useful tool to investigate head injury mechanism, there has not been a research result using a model considering the structural and qualitative changes of the brain by aging. The objective of this study was to clarify the generational difference of intracranial responses related to traumatic brain injuries (TBI) under impact loading.In this study, the human head/brain FE models in their twenties (20s) and seventies (70s) were used. They were developed by reflecting the age-specific characteristics, such as shape/size and stiffness of brain matter and blood vessels, to the baseline model developed by Global Human Body Models Consortium (GHBMC) LLC. The generational difference of intracranial responses related to TBI, such as cumulative strain damage measure (CSDM), dilatational damage measure (DDM) and elongation of bridging vein (BV), were studied using the models.From the study of the generational…
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Validation of Age-Specific Human FE Models for Lateral Impact

Honda R&D Co.,Ltd.-Yasuhiro Dokko, Toshiyuki Yanaoka
PSG Co., Ltd.-Kazuki Ohashi
Published 2013-04-08 by SAE International in United States
Corresponding to the increasing need for the protection of elderly people from traffic accidents, the authors have been developing age-specific human FE models capable of predicting body kinematics and skeletal injuries for younger adult (35y.o.) and the elderly (75y.o.). The models have been developed and validated part by part referring to the literature and then integrated into whole bodies. Validation had been conducted in order of single bones, components and whole body. Whole body kinematics in frontal impact had been validated against the PMHS frontal belt restrained sled tests series, resulting in good biofidelity scores. In this study, the models were validated for lateral impact. The models were validated against several impact tests of body regions from ISO-TR9790 and against recently published full scale lateral sled tests for whole body kinematics. In most cases, the results showed good biofidelity of the models. Capability of the rib fracture prediction was also discussed.
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Kinematics Validation of Age-Specific Restrained 50th Percentile Occupant FE Model in Frontal Impact

Honda R&D Co., Ltd.-Yuichi Ito, Yasuhiro Dokko, Yasuki Motozawa
PSG-Fumie Mori, Kazuki Ohashi
Published 2012-04-16 by SAE International in United States
Recently, the global increase of elderly vehicle users has become an issue to be considered in the effort of enhancing safety performance of vehicle restraint system. It is thought that an evaluation tool for the system representing properties of age-specific human body will play a major role for that. In previous research, the authors had developed age-specific component finite element (FE) models for the lower limb, lumbar spine, and thorax representing the adult and elderly occupants. However, the models have not been validated in terms of full body kinematics. It is essential for such models to be validated in terms of full body kinematics in order to ensure validity of the results of the assessment of the safety performance of restraint systems.In the present research, the adult and elderly occupant full body FE models were developed by incorporating the lower limb, lumbar spine and thorax of the adult and elderly FE models established in previous research. To represent the kinematics of the shoulder of the adult occupant model, the shoulder girdle muscles were modeled and…
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Kinematics Validation of the Adult and Elderly Occupant FE Models Against Frontal Impact Sled Tests

Honda R&D-Yuichi Ito, Osamu Ito, Yasuhiro Dokko, Yasuki Motozawa
PSG-Fumie Mori, Kazuki Ohashi
  • Technical Paper
  • 2011-08-0348
Published 2011-10-12 by Society of Automotive Engineers of Japan in Japan
The full body kinematics of the adult and elderly FE models incorporating the thorax, lower limb and lumbar spine models were validated against the frontal sled test. The properties of the shoulder muscle were modified with reference to published thoracic belt loading table-top test results. It was found important to adjust the initial posture of the models to the Post Mortem Human Subject (PMHS) in order to get good agreement in the full body kinematics between the models and the PMHS.
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Validation of Adult and Elderly FE Thorax Models Against the Age-Specific Corridors of Chest Impact

Honda R&D-Yasuhiro Dokko, Osamu Ito, Yuichi Ito
PSG-Fumie Mori, Kazuki Oohashi
  • Technical Paper
  • 2011-08-0349
Published 2011-10-12 by Society of Automotive Engineers of Japan in Japan
To validate the human thorax FE models for adult and the elderly against their respective corridors of frontal chest impact tests, they were developed by reanalyzing the published data based on which the Part 572 chest impact corridors for dummy development and calibration were developed. The screened data were divided into two age groups and then average and standard deviations were calculated to obtain a couple of corridors. The chest impact response from the human FE model of each age was compared with each age corridor, which showed good agreement.
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Successive Development of Adult and Elderly FE Thorax Models

Honda R&D Co., Ltd.-Osamu Ito, Yuichi Ito, Yasuhiro Dokko
PSG Co., Ltd.-Fumie Mori, Kazuki Ohhashi
  • Technical Paper
  • 2010-08-0634
Published 2010-09-29 by Society of Automotive Engineers of Japan in Japan
The adult and elderly FE thorax models reported at 2009 JSAE Spring Congress could achieve less biofidelity in chest impact, one of the reasons for which was assumed to be less biofidelic bone models other than ribs developed with few biomechanics data published. In this study, the sternum and the costal cartilage models were updated referring newly published test results. Incorporating these bone models, the thorax models showed improved response in chest impact.
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Development of Human Lumbar Spine FE Models for Adult and the Elderly

Honda R&D Co., Ltd.-Yu Kanayama, Yasuhiro Dokko, Osamu Ito
PSG Co., Ltd.-Kazuki Ohashi
  • Technical Paper
  • 2009-08-0214
Published 2009-05-20 by Society of Automotive Engineers of Japan in Japan
In connection with lowering birthrate and longevity, the ratio of traffic accidents in which elderly people are involved in increasing, and the need for elderly injury mitigation is also increasing. In this study, human FE models capable of evaluating lumbar spine injuries for adult and the elderly were developed incorporating the changes of the material characteristics and bone geometry of the lumbar spine due to aging investigated and quantified from the literature. The models were validated against the test results for corresponding age groups from the literature.
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Development of Thorax Skeletal FE Models for Adult and the Elderly

Honda R&D Co., Ltd.-Osamu Ito, Yasuhiro Dokko
PSG Co., Ltd.-Kazuki Ohashi
  • Technical Paper
  • 2009-08-0213
Published 2009-05-20 by Society of Automotive Engineers of Japan in Japan
Human thorax FE models for evaluating thoracic skeletal injuries both on adult and the elderly were developed. The rib cage geometries were generated based on the medical CT images and the literature. The material properties of the rib, costal cartilage and the clavicle were estimated based on the literature, and for the sternum, the material property of the rib was used. The models were validated against isolated bone bending and chest impact tests from the literature.
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Development of Human Lumbar Spine FE Models for Adult and the Elderly

Honda R&D Co., Ltd-Yasuhiro Dokko, Yu Kanayama, Osamu Ito
PSG Co., Ltd-Kazuki Ohashi
Published 2009-04-20 by SAE International in United States
For occupant protection in vehicle crash, several kinds of ATDs (Anthropomorphic Test Devices) and associated injury criteria have been used to evaluate the performance of a vehicle body, restraint systems and other safety devices. Because of the lack of sufficiently validated injury criteria for the lumbar spine, it has been a concern that the effectiveness of some safety features for injury reduction based on the dummy and associated injury criteria may not be reasonably assessed. Therefore, in this study, a human FE model capable of evaluating lumbar spine skeletal injuries was developed. Considering an increasing percentage of the traffic accidents relating to elderly people due to extending span of human life and decreasing birthrate, not only an adult model but also a model that represents lowered tolerance of the elderly was developed. From traffic accident statistics, 35 and 75 years old (y.o.) were defined as the representative ages of adult and elderly populations. An existing human FE model for an adult male was adopted for the baseline. The material properties of the trabecular bone of…
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