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A Design and Optimization Method for Pedestrian Lower Extremity Injury Analysis with the aPLI Model

Changan Automobile Co., Ltd.-Ruyi Chen
Chongqing University-Yue Fu, Huijie Xu, Guan Lin, Zhenfei Zhan, Ping Wang
  • Technical Paper
  • 2020-01-0929
To be published on 2020-04-14 by SAE International in United States
As pedestrian protection tests and evaluations have been officially incorporated into new C-NCAP, more stringent requirements have been placed on pedestrian protection performance. In this study, in order to reduce the injury of the vehicle front end structure to the pedestrian's lower extremity during the collision, the advanced pedestrian legform impactor (aPLI) model was used in conjunction with the finite element vehicle model for collision simulation based on the new C-NCAP legform test evaluation regulation. This paper selected the key components which have significant influences on the pedestrian's leg protection performance based on the CAE vehicle model, including front bumper, front-cover plate, upper impact pillar, impact beam and lower support plate, to form a simplified model and conducted parametric modeling based on it. Then, the variable correlation analysis was carried out on the sample results obtained from the design of experiment (DOE), and the contribution analysis of design variables to the injury measures was discussed. The sample variables and responses were also used to construct the approximate models for further optimization studies. Taking the pedestrian…
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Patient Demographics and Injury Characteristics of ER visits Related to Powered Scooters

Exponent, Inc.-Heather N Watson, Christina MR Garman, Jeffrey Wishart, Jacqueline Zimmermann
  • Technical Paper
  • 2020-01-0933
To be published on 2020-04-14 by SAE International in United States
Electric scooters (e-scooters) have become increasingly popular in the U.S. In 2018, e-scooters usage overtook other shared micro-mobility transportation modes, including bike shares; over 38 million trips were taken on e-scooters. As the popularity increases, so does the societal concern regarding the safety of these devices. To examine the types of injuries associated with e-scooters and the injury rate per trip at a national level, the National Electronic Injury Surveillance System (NEISS), a probability sample of US Hospitals that collects information from emergency room visits related to a consumer product, was utilized. Records from September 2017 to December 2018 were extracted, and those associated with powered scooters were identified. Injury distributions by age, sex, race, treatment, diagnosis and location on the body were explored. The number of person-trips was obtained to perform a risk analysis. Between September 2017 and December 2018, an estimated 17,772 injuries were associated with powered scooters. Nearly 45% of injuries occurred in persons aged 10-29 years and males tended to sustain a higher proportion of injuries compared to females. Almost 87%…
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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 widely 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. The trailer was filled with concrete blocks and attached to a 2001 Kenworth tractor. 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, upper/lower tibia moments, upper/lower tibia indices, tibia axial forces, and foot accelerations were measured. The vehicle accelerations, vehicle delta-Vs, and occupant compartment intrusions were also evaluated during these crash tests. The results indicated that the head and neck injury parameters were correlated with driver A-pillar rearward intrusion. The 30% overlap crashes showed significantly higher intrusion and head and neck injury values than…
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A Hybrid Material Automotive Bumper Beam for Enhanced Safety of Both Occupant and Pedestrian

Dalian University of Technology-Chang Qi, Yong Sun, Shu Yang
Tsinghua University-Zhen-Hua Lu
  • Technical Paper
  • 2020-01-0201
To be published on 2020-04-14 by SAE International in United States
In vehicle accident, the bumper beam generally requires high stiffness for sufficient survival space for occupants while it may cause serious pedestrian lower extremity injuries. The aim of this study is to promote an aluminum-steel hybrid material double-hat bumper to meet the comprehensive requirements. The proposed hybrid bumper beam is comprised of an aluminum alloy upper hat and a high strength steel (HSS) lower hat. The two hats are riveted together by steel rivets. The hybrid bumper is designed to improve the frontal crash and pedestrian protection performances in collision accidents. In a low-velocity impact scenario with a pedestrian, the aluminum upper hat helps to reduce the lower extremity injuries of the pedestrian, while in a high-velocity impact case with a rigid object, e.g., a tree or electric pole, the HSS lower hat could prevent excessive intrusion into the engine compartment and the passenger compartment, so as to prevent occupant injury. Finite element (FE) models of the hybrid bumper was built, validated, and integrated into an automotive. The Fixed Deformable Barrier (FDB) and Transport Research…
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Comparison of Kinematics of Different Combinations of Bicyclists and Impact Vehicles

Nissan Motor Co., Ltd.-Chinmoy Pal, Shigeru Hirayama
RNTBCI-Pratap Naidu Vallabhaneni, Kulothungan Vimalathithan, Jeyabharath Manoharan
  • Technical Paper
  • 2020-01-0932
To be published on 2020-04-14 by SAE International in United States
This study focusses on new head protection evaluation procedure for bicyclists as proposed by BASt in recent publications. This paper is focused on change in kinematics of a bicyclist when different shapes of vehicle front-end impact with different bicyclists at intersection. Bicycle and Bicyclist FE models are developed using side impact dummies and HBMs (GHBMC). Bicyclist’s head kinematics and head injury are analyzed in detail. It is found that (a) existing Pop-up vehicles are effective (b) Overall kinematics of the bicyclist will be more influenced by the relative orientations of the two legs while pedaling at the time of impact than that of a pedestrian while walking and (c) the relative position (difference in height) of BLE (bonnet leading edge) and CG of the bicyclist from ground especially the hip of bicyclist is one of the most influential parameter for WAD, the distance of the impact point of the head from ground.
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Biofidelity of THOR 5th Percentile Female ATD in Ankle Eversion and Inversion

University of Virginia-Shubham Kulkarni, Carolyn Roberts, Patrick Foltz, Jason Forman
  • Technical Paper
  • 2020-01-0528
To be published on 2020-04-14 by SAE International in United States
Females have higher frequency and risk of foot and ankle injuries in motor vehicle collisions than similar-sized males. Therefore, lower extremity biofidelity and accurate injury prediction of female ATDs is critical. This paper aims to compare the THOR 5th percentile female (THOR-05F) anthropomorphic test device (ATD) response with male and female PMHS data of various sizes under ankle inversion and eversion. The THOR-05F lower extremity was subjected to dynamic inversion and eversion ankle loading with a constant 2000N axial force applied through the tibia. Twelve THOR-05F tests (3 inversion and 3 eversion on both, left and right legs) were performed with boundary conditions consistent with previous post-mortem human subject (PMHS) lower extremity tests. The biofidelity of THOR-05F ankle stiffness was evaluated via comparison of measured and equal-stress equal-velocity scaled data (using mass-based scale factors) from previous PMHS datasets with mid-size males, small females and larger females. THOR-05F ankle moment-angle response falls within the range of previous mid-sized male and larger female PMHS test data for eversion, when scaled to a small female. However, when compared…
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Kinematic and Biomechanical Response of Post-Mortem Human Subjects Under Various Pre-Impact Postures to High-Rate Vertical Loading Conditions

Emory University, Atlanta, GA-Jonathan D Rupp
The John Hopkins University Applied Physics Laboratory, Laur-Constantine K Demetropoulos, Kyle A Ott, Christopher J Dooley, Nathanael P Kuo, Leah M Strohsnitter, Joseph R Andrist, Mary E Luongo, David G Drewry III, Andrew C Merkle
  • Technical Paper
  • 2019-22-0010
Published 2020-03-31 by The Stapp Association in United States
Limited data exist on the injury tolerance and biomechanical response of humans to high-rate, under-body blast (UBB) loading conditions that are commonly seen in current military operations, and there are no data examining the influence of occupant posture on response. Additionally, no anthropomorphic test device (ATD) currently exists that can properly assess the response of humans to high-rate UBB loading. Therefore, the purpose of this research was to examine the response of post-mortem human surrogates (PMHS) in various seated postures to high-rate, vertical loading representative of those conditions seen in theater. In total, six PMHS tests were conducted using loading pulses applied directly to the pelvis and feet of the PMHS: three in an acute posture (foot, knee, and pelvis angles of 75°, 75°, and 36°, respectively), and three in an obtuse posture (15° reclined torso, and foot, knee, and pelvis angles of 105°, 105°, and 49.5°, respectively). Tests were conducted with a seat velocity pulse that peaked at ~4 m/s with a 30-40 ms time to peak velocity (TTP) and a floor velocity that…
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Analysis of Force Mitigation by Boots in Axial Impacts using a Lower Leg Finite Element Model

Dept. of Neurosurgery, Medical College of Wisconsin at Zablo-Michael Schlick, Narayan Yoganandan, Frank A. Pintar
U.S. Army Research Laboratory, CCDC-WMRD, Aberdeen Proving G-Carolyn E. Hampton, Michael Kleinberger
  • Technical Paper
  • 2019-22-0011
Published 2020-03-31 by The Stapp Association in United States
Lower extremity injuries caused by floor plate impacts through the axis of the lower leg are a major source of injury and disability for civilian and military vehicle occupants. A collection of PMHS pendulum impacts was revisited to obtain data for paired booted/unbooted test on the same leg. Five sets of paired pendulum impacts (10 experiments in total) were found using four lower legs from two PMHS. The PMHS size and age was representative of an average young adult male. In these tests, a PMHS leg was impacted by a 3.4 or 5.8 kg pendulum with an initial velocity of 5, 7, or 10 m/s (42-288 J). A matching LS-DYNA finite element model was developed to replicate the experiments and provide additional energy, strain, and stress data. Simulation results matched the PMHS data using peak values and CORA curve correlations. Experimental forces ranged between 1.9 and 12.1 kN experimentally and 2.0 and 11.7 kN in simulation. Combat boot usage reduced the peak force by 36% experimentally (32% in simulation) by compressing the sole and insole…
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Footrest Design to Reduce Lower Leg Injury in Frontal Crashes

General Motors do Brazil-Tsuguo Eduardo Kimura, Gilvan Prada Rossi, Paulus Hanser de Freitas
  • Technical Paper
  • 2019-36-0090
Published 2020-01-13 by SAE International in United States
The frontal impact is the most common vehicle crash type in accidents involving cars. During a vehicle frontal impact, the injuries are caused by occupant body moving forward and impacting the vehicle interior parts. The performance of the vehicle body and the interior parts design may influence on the occupant injury levels. Injuries in the occupant lower body are usually affected by the vehicle lower body deformation and the design of the interior lower parts (lower instrument panel, pedals, floor and footrest). When the purpose is to reduce the injury of a specific body region, the modification of the interior part design can be more effective in terms of impacts in mass, costs and development time than a modification in the vehicle body. The objective of the study was to develop a new footrest design to reduce the injury level of the left driver leg in a frontal crash condition. It was also evaluated the influence of the vehicle body deformation on the driver leg injury. There were manufactured footrest prototypes with different shapes and…
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Wireless Sensor “Stickers” Track Physiological Signals

  • Magazine Article
  • TBMG-35823
Published 2020-01-01 by Tech Briefs Media Group in United States

Engineers have developed a way to detect physiological signals emanating from the skin with sticky sensors that beam wireless readings to a receiver clipped onto clothing. To demonstrate the wearable technology, the researchers stuck sensors to the wrist and abdomen of a test subject to monitor the person's pulse and respiration by detecting how their skin stretched and contracted with each heartbeat or breath. Likewise, stickers on the person's elbows and knees tracked arm and leg motions by gauging the minute tightening or relaxation of the skin each time the corresponding muscle flexed.