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Biomechanics of Passenger Vehicle Underride: An Analysis of IIHS Crash Test Data

Vollmer-Gray Engineering Laboratories-Mohammad Atarod
  • Technical Paper
  • 2020-01-0525
To be published on 2020-04-14 by SAE International in United States
Occupant dynamics during passenger vehicle underride has not been extensively evaluated. The present study examined the occupant data from IIHS rear underride crash tests. A total of 35 crash tests were evaluated. The tests were classified as full-width (n = 9), 50% overlap (n = 11), and 30% overlap (n = 15). A 2010 Chevrolet Malibu impacted the rear underride guard of a stationary trailer at 35 mph. Several occupant kinematics and dynamics data including head accelerations, head injury criteria, neck shear and axial forces, neck moments, neck indices, chest acceleration, chest displacement, chest viscous criterion, sternum deflection rate, and left/right femur forces/impulses, knee displacements, tibia axial forces, upper/lower tibia moments, upper/lower tibia indices, and foot accelerations were measured. The vehicle accelerations, delta-Vs, and occupant compartment intrusions were also evaluated. The results indicated that the head and neck injury parameters were positively correlated with driver A-pillar rearward intrusion. The 30% overlap crashes showed significantly higher intrusion and head and neck injury values than the 50% and full-width crashes. No strong relationship between head and neck…
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Pedestrian Orientation Estimation Using CNN and Depth Camera

Oakland University-Karam Abughalieh, Shadi Alawneh
  • Technical Paper
  • 2020-01-0700
To be published on 2020-04-14 by SAE International in United States
This work presents a method for estimating human body orientation using a combination of convolutional neural network (CNN) and stereo camera in real time. The approach uses the CNN model to predict certain human body keypoints then transforms these points into a 3D space using the stereo vision system to estimate the body orientations. The CNN module is trained to estimate the shoulders, the neck and the nose positions, detecting of three points is required to confirm human detection and provided enough data to translate the points into 3D space.
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Occupant Dynamics during Moderate-to-High Speed Rear-End Collisions

Vollmer-Gray Engineering Laboratories-Mohammad Atarod
  • Technical Paper
  • 2020-01-0516
To be published on 2020-04-14 by SAE International in United States
Numerous studies have evaluated occupant kinematics and dynamics in “low-speed” rear-end impacts (delta-V ≤ 8 mph). Occupant biomechanics during “moderate-to-high” speed rear impacts (9 ≤ delta-V ≤ 20 mph) has not been thoroughly examined. This study characterized the motions and forces experienced by the head, neck, torso, hip, and left/right femur during these collisions. The publicly available NHTSA rear-end crash test data were examined. More specifically, the FMVSS 301 Fuel System Integrity tests were used. The test procedure involved a 30 mph moving barrier impacting the rear of the vehicles. Instrumented 50th-percentile male (N = 47) or 5th-percentile female (N = 4) Hybrid III ATDs were positioned in the driver seat. Occupant data including head accelerations, upper/lower neck shear and axial forces, upper/lower neck moments, lower neck acceleration, torso accelerations, torso deflection, hip accelerations, and left/right femur axial forces were evaluated and compared to published injury tolerance data. The vehicle accelerations, vehicle delta-Vs, occupant position data, seat angular velocity, seat rotation and seatbelt forces and pullout were also examined. Target vehicle peak accelerations were 22.9…
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The Effect of Active and Conventional Head Restraints on Front Seat Occupant Responses in 16 km/h Rear Impacts

Exponent Inc.-Chantal Parenteau, Ian C. Campbell, Stephanie A. Pasquesi
  • Technical Paper
  • 2020-01-1217
To be published on 2020-04-14 by SAE International in United States
This study assesses front seat occupant responses in rear impacts with active head restraints (AHR) and conventional head restraints (CHR) using field accident data and test data from the Insurance Institute for Highway Safety (IIHS). 2003-2015 NASS-CDS data were analyzed to determine the injury rate in 1997+ model year seats equipped with AHR and CHR. Results indicated that only 3.1% of occupants were in seats equipped with AHR. More than 58% of occupants were uninjured, irrespective of AHR presence. In <24 km/h delta-V crashes, AHRs were 35.6% effective in reducing MAIS 1-2 injury overall and 26.4% in reducing MAIS 1-2 cervical injury. In IIHS 16 km/h rear sled tests, an instrumented BioRID was evaluated on seats with AHR and CHR. The biomechanical responses were analyzed. HIC15 and concussion risk were calculated from head acceleration data. Test data with AHR and CHR were matched by make and model. First, older model seats with CHR were compared to models with AHR. Then, the models with AHR were compared to newer models with CHR. These analyses showed a…
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Injury Rates by Crash Severity, Belt Use and Head Restraint Type and Performance in Rear Impacts

Exponent Inc.-Chantal Parenteau, Bruce Miller
Ford Motor Company-Roger Burnett
  • Technical Paper
  • 2020-01-1223
To be published on 2020-04-14 by SAE International in United States
This study assesses the exposure distribution and injury rate (MAIS 4+F) to front-outboard non-ejected occupants by crash severity, belt use and head restraint type and damage in rear impacts using 1997-2015 NASS-CDS data. Rear crashes with a delta V <24 km/h (15 mph) accounted for 71% of all exposed occupants. The rate of MAIS 4+F increased with delta V and was higher for unbelted than belted occupants with a rate of 11.7% ± 5.2% and 6.0% ± 1.5% respectively in 48+ km/h (30 mph) delta V. Approximately 12% of front-outboard occupants were in seats equipped with an integral head restraint and 86% were with an adjustable head restraint, irrespective of crash severity. The overall injury rate was 0.14% ± 0.05% and 0.22% ± 0.06%, respectively. It was higher in cases where the head restraint was listed as “damaged”. Thirteen cases involving a lap-shoulder belted occupant in a front-outboard seat in which “damage” to the adjustable head restraint was identified. Review of these cases showed that intrusion and crash severity were important factors and that the…
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A Preliminary Study on the Restraint System of Self-Driving Car

Hunan University-Binhui Jiang, Hongze Ren, Zhonghao Bai
The Johns Hopkins University-Feng Zhu
  • Technical Paper
  • 2020-01-1333
To be published on 2020-04-14 by SAE International in United States
Due to the variation of compartment design and occupant’s posture in self-driving cars, there is a new and major challenge for occupant protection. In particular, the studies on occupant restraint systems used in the self-driving car have been significantly delayed compared to the development of the autonomous technologies. In this paper, a numerical study was conducted to investigate the effectiveness of three typical restraint systems on the driver protection in three different scenarios. It is found that based on the simulation results: (1) All the restraint systems are capable of providing effective protection for the driving driver and the 4-point belt restraint system has advantages due to its better protective effect on the occupant thorax; (2) When the driver is in half-reclining and reclining resting modes, head HIC36, neck Nij and chest compression are about 572.9-1524.3, 0.64-1.47, and 14.7-48.3 mm, respectively; These values are higher than those of a driving driver by 0.2%-198.3% for HIC36, 113.3%-359.4% for neck Nij, and -59.6%-79.8% for chest compression, respectively. (3) There is an evident “submarining” of dummy in the…
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Innovative Active Head Restraint System in a Car: Safety Assessment with Virtual Human Body Model

Mecas ESI S.r.o-Jana Hlucha, Ludek Kovar
Transport Research Centre-Martina Kostikova, Pavlina Moravcova, Katerina Bucsuhazy
  • Technical Paper
  • 2020-01-0979
To be published on 2020-04-14 by SAE International in United States
The aim of this study is to use numerical simulations for safety assessment of an innovative active head restraint system. This system was developed to protect the head and neck of an occupant in a car without a head airbag during a side impact. Its FE model is created and embedded it in a model of a small car with a side airbag. The dynamics of the head restraint activation are also taken into account. The virtual human body model Virthuman is used to represent occupants. The model is scaled for pre-selected human individuals to cover large numbers of occupants of different sizes. It extends conventional virtual evaluation of new safety designs via existing pre-defined mono-purpose side dummies and their FE models. The benefit of the head restraint system is evaluated in side impact scenarios inspired by the pole tests performed by EuroNCAP. Transversal impacts to a pole at 29 and 32 km/h are considered at 90° and 75° angles from driver and the opposite side. Also, the far side impact prescribed with an acceleration…
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Far Side Impact Injury Threshold Recommendations Based on 6 Paired WorldSID / Post Mortem Human Subjects Tests

CEESAR (Nanterre - France)-Jérome Uriot, David Poulard, Pascal Potier, Pascal Baudrit
LAB PSA Peugeot Citroën Renault (Nanterre - France)-Philippe Petit, Xavier Trosseille
  • Technical Paper
  • 2019-22-0005
Published 2020-03-31 by The Stapp Association in United States
Far side has been identified in the literature as a potential cause of numerous injuries and fatalities. Euro NCAP developed a far side test protocol to be performed to assess adult protection. A monitoring phase was undertaken between January 2018 and December 2019, and the far side assessment will become part of the rating for all vehicles launched in 2020 onward.A test buck was developed and 6 paired WorldSID / Post Mortem Human Subjects (PMHS) were subjected to the test protocol proposed by Euro NCAP to contribute to the development of limits. The buck consisted of a rigid seat and a rigid central console covered with 50 mm of Ethafoam TM 180 with a density of 16 kg/m3. The buck was mounted on the sled with an angle of 75° between the X axis of the vehicle and the X axis of the sled.The peak head excursion was compared between PMHS and the WorldSID dummy. It was found reasonably similar. However, the dummy repeatability was found to be poor.Out of 6 tests conducted on 6…
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Passenger Injury Analysis Considering Vehicle Crash after AEB Activation

Hyundai Mobis-Seokhoon Ko, Garam Jeong, Dohyung Kim, Haekwon Park, Kyusang Lee, Raeick Jang
  • Technical Paper
  • 2019-22-0023
Published 2020-03-31 by The Stapp Association in United States
Owing to an increasing autonomous emergency braking (AEB) adoption, emergency braking before crash occurs more often than in the case of conventional vehicles. Due to the sudden deceleration in AEB activation, passengers move forward before the crash. To explore how this forward movement affects passenger injury, sled tests are performed with an inclined dummy representing forward displacement. The test shows that a shorter distance between the airbag and passenger results in bigger neck injuries induced by airbag deployment force. A countermeasure is suggested to prevent neck injury in emergency braking situation by reducing deployment force and protrusion.
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Head Support Concept to Mitigate Neck Injury for Children Installed Forward Facing in Vehicles

General Motors of Brazil-Rodrigo da Silva Ribeiro
Unicamp-Antonio Celso Fonseca De Arruda
  • Technical Paper
  • 2019-36-0106
Published 2020-01-13 by SAE International in United States
The slender neck of a 3-year-old child can be serious injured or even lead to child’s death when loaded under frontal impact by the proportionately larger and heavier head. Accordingly with medical recommendations based on latest studies, a 3-year-old child is safer when installed in a rear-facing child seat, but this configuration is not feasible for some vehicles with limited rear space such as superminis, small MPVs and pick-ups when front seats are occupied. This study aims to explore the potential of neck tension (Fz) reduction in 3-year-old dummy installed forward-facing when subjected to three head static restraints (head strap, head support, cervical collar) as well as an overhead shield car seat in order to identify solutions for a device to avoid or mitigate neck injuries. To simulate frontal impacts, a 3-year-old dummy from Q series was installed on a reinforced vehicle body fixed on a sled test equipment where the United Nations R129 pulse was applied. Both head strap and head support were not able to reduce neck tension due to the high Q3…
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