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Technical Paper

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

2015-04-14
2015-01-1439
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.
Technical Paper

Investigation on Generational Difference of Intracranial Responses Related to Traumatic Brain Injuries Using Age-Specific Human Head/Brain FE Models

2014-04-01
2014-01-0485
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.
Technical Paper

Validation of Age-Specific Human FE Models for Lateral Impact

2013-04-08
2013-01-1242
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.
Technical Paper

Kinematics Validation of Age-Specific Restrained 50th Percentile Occupant FE Model in Frontal Impact

2012-04-16
2012-01-0565
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.
Technical Paper

Development of Human Lower Limb and Pelvis FE Models for Adult and the Elderly

2009-04-20
2009-01-0396
It has been difficult to evaluate injuries to the elderly whose body tolerance is lowered due to aging. The objective of this study was to develop human FE models for evaluating skeletal injuries to the lower limb and pelvis of both adult and elderly people. From traffic accident statistics, 35 and 75 years old (y.o.) were defined as the representative ages of adult and elderly population. An existing human FE model for an adult male pedestrian was adopted for the baseline. Femur models were developed first, because there existed most sufficient data of material properties and geometry for the femur. Age-related changes in material properties and geometries of bone were investigated by literature survey, from which average values of Young’s modulus, yield stress/strain and ultimate stress/strain, section areas and cortical bone thicknesses for 35 and 75 y.o. were determined.
Technical Paper

Development of Adult and Elderly FE Thorax Skeletal Models

2009-04-20
2009-01-0381
Accident statistics show that the thorax is one of the most frequently injured body regions in drivers who sustain severe injuries in frontal car crashes. Thoracic injuries are more significant for the elderly than for adults. However, there are no injury assessment tools accounting for differences in anatomical features and material properties between adults and the elderly. The current study developed adult and elderly FE thorax models for investigating thoracic injury mechanisms for each generation. The ages represented by these models were defined as 35 and 75 years old (y.o.), respectively, based on the age distribution from accident statistics. The FE meshes representing the external shapes of the thoracic skeleton were first created based on the thorax CT images of the individuals with approximately average body sizes of males in their 30’s and 70’s.
Technical Paper

A Comparative Evaluation of Pedestrian Kinematics and Injury Prediction for Adults and Children upon Impact with a Passenger Car

2004-03-08
2004-01-1606
Studies show that the pedestrian population at high risk of injury consists of both young children and adults. The goal of this study is to gain understanding in the mechanisms that lead to injuries for children and adults. Multi-body pedestrian human models of two specific anthropometries, a 6year-old child and a 50th percentile adult male, are applied. A vehicle model is developed that consists of a detailed rigid finite element mesh, validated stiffness regions, stiff structures underlying the hood and a suspension model. Simulations are performed in a test matrix where anthropometry, impact speed and impact location are variables. Bumper impact occurs with the tibia of the 50th percentile adult male and with the thigh of the 6-year-old child. The head of a 50th percentile male impacts the lower windshield, while the 6-year-old child's head impacts the front part of the hood.
Technical Paper

A Multi-Body Computational Study of the Kinematic and Injury Response of a Pedestrian with Variable Stance upon Impact with a Vehicle

2004-03-08
2004-01-1607
This research investigates the variation of pedestrian stance in pedestrian-automobile impact using a validated multi-body vehicle and human model. Detailed vehicle models of a small family car and a sport utility vehicle (SUV) are developed and validated for impact with a 50th percentile human male anthropometric ellipsoid model, and different pedestrian stances (struck limb forward, feet together, and struck limb backward) are investigated. The models calculate the physical trajectory of the multi-body models including head and torso accelerations, as well as pelvic force loads. This study shows that lower limb orientation during a pedestrian-automobile impact plays a dominant role in upper body kinematics of the pedestrian. Specifically, stance has a substantial effect on the subsequent impacts of the head and thorax with the vehicle. The variation in stance can change the severity of an injury incurred during an impact by changing the impact region.
Technical Paper

DEVELOPMENT OF A WHIPLASH INJURY REDUCING SEAT SYSTEM USING BIORID II DUMMY

2001-06-04
2001-06-0057
In recent years, several kinds of seat systems that aim to reduce cervical spinal injuries in rear impacts, so called ‘whiplash injuries’, have been released by some car manufacturers and seat suppliers in the world. Meanwhile, several kinds of dummies have been developed to be representatives of occupants under such conditions. One of these is the BioRID II equipped with a realistic spine constructed of multiple vertebrae similar to that of a human. It is regarded as the most biofidelic dummy for low speed rear impact. Using this dummy, some typical ‘whiplash protective’ seat systems currently available were dynamically tested to see their performance on injury reduction. From the results of these tests, the design direction to lessen the injury level more efficiently was determined.
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