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Lightweight design of automotive front end material-structure based on frontal collision

Nanjing University of Science & Technology-JIANGFAN ZHANG
Naveco, Ltd.-Xiaojun Zou, Liu-kai Yuan, Hualin Zhang
  • Technical Paper
  • 2020-01-0204
To be published on 2020-04-14 by SAE International in United States
The front end structure is an important role in protecting the vehicle and passengers from harm during the collision. Increasing its protective capacity can be achieved by increasing the thickness or replacing high-strength materials. Most of the current research is analyzed separately from these two aspects. This paper proposes a multi-objective optimization method based on agent model, which combines material and thickness selection. First, the optimized components are determined based on the 100% frontal collision simulation results. Secondly, six thicknesses and four materials of the front part of the vehicle body are selected as design variables to construct a material-structure integrated multi-objective optimization model. Taking the total mass and energy absorption of the research object as the optimization target, the B-pillar acceleration and the maximum intrusion of the dash panel are used as constraints, using the radial basis (RBF) proxy model and the second generation non-dominated genetic algorithm (NSGA-II) for lightweight design, the Pareto solution set is obtained, This optimization method can select the best material and component thickness combination scheme. Finally, by comparing the…
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A Human Body Model Study on Restraints for Side-Facing Occupants in Frontal Crashes of an Automated Vehicle

Joyson Safety Systems-Maika Katagiri, Sungwoo Lee
Joyson Safety Systems, NA-Jay Zhijian Zhao
  • Technical Paper
  • 2020-01-0980
To be published on 2020-04-14 by SAE International in United States
This study is to investigate kinematics and responses of side-facing seated occupants in frontal crashes of an automated minivan using Global Human Body Models Consortium (GHBMC) simplified occupant models (50th%ile male and 5th%ile female), and to develop new restraint concepts to protect the occupants. The latest GHBMC M50-OS and F05-OS models (version 2.1) were further validated with the Postmortem Human Subject (PMHS) side sled tests [Cavanaugh 1990] and the PMHS far-side sled tests [Formen 2013], with detailed correlations of the kinematics and the injury measures. Robustness and biofidelity of the GHBMC human models, especially for the pelvis and knee body regions, were further improved. Using the improved M50-OS and F05-OS models, we evaluated the body kinematics and injury measures of the side-facing seated occupants in frontal crashes at severities ranging from 15 mph to 35 mph. Three restraint conditions were studied: 1) no restraint; 2) lap belt only; 3) lap belt and conceptual inflatable device. An additional parametric study on the restraint design parameters of the #3 restraint concept was performed to “optimize” the restraint…
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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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Update on Second-Row Children Responses in Rear and Frontal Crashes with a Focus on the Potential Effect of Stiffening Front Seat Structures

Exponent Inc.-Chantal Parenteau
ProBiomechanics LLC-David Viano
  • Technical Paper
  • 2020-01-1215
To be published on 2020-04-14 by SAE International in United States
The protection of children in rear seats is an important issue, but it is a more complex than assessing front seat performance in rear impacts. 1997–2015 NASS-CDS data were analyzed to estimate the distribution and risk of seriously-to-fatally (MAIS 3+F) injured 0-7 year old children in the 2nd row by crash types with 1994+ model year vehicles. The results showed that children were frequently injured in frontal (39.3%) and in side (27.2%) crashes. The injury risk was highest in rollover (1.72% ± 0.36) followed by rear crashes (0.75% ± 0.56%). Individual rear and frontal impact cases were also reviewed to better understand injury mechanisms of children in the 2nd row. The cases were downloaded and reviewed. There were 15 injured children involved in 14 rear impact crashes. Half were associated with significant intrusion (12+ inches) intrusion of their seating area, pushing the child forward. More than half (7 out of 11 cases with known information) of the front seatbacks remained in their pre-crash position or were pushed forward. Rear crashes involving the front-seat rotating rearward…
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The effects of small seat swiveling angles on occupant responses during a frontal impact

LAB PSA RENAULT-Xavier Trosseille, Philippe Petit
Univ. Lyon 1, Univ. Eiffel, IFSTTAR , LBMC-Cyrille Grébonval, Xuguang Wang, Philippe Beillas
  • Technical Paper
  • 2020-01-0571
To be published on 2020-04-14 by SAE International in United States
In highly automated vehicles (HAV), new seat configurations may allow occupants to perform new activities. Among other designs, current HAV concepts include swiveled seats, which might facilitate communication between occupants. The objective of this study was to investigate the effects of seat swiveling angle on occupant kinematics and injury criteria predicted by a Human Body Model (HBM) during a frontal impact. A detailed 50th percentile HBM (GHBMC M50-O) was subjected to two frontal crash pulses in a sled setup. The model was positioned on a semi-rigid seat and restrained using a pre-inflated airbag and a three-point seatbelt. Simulations included three seat swiveling angles (0, -10, -20, and -30 degrees ), three occupant positions (Sedan driver, large VAN driver or Laptop user), two airbag initial locations (nominal or matching the head Y location), and the inclusion of seat pan lateral supports. With the airbag in the nominal location, higher seat swiveling angles led to more head lateral displacement and higher values of head injury criteria, especially for the BrIC. This was mitigated by aligning the airbag…
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Frontal Crash Worthiness Performance of Bitubular Corrugated Conical Structures under both axial and oblique loads at low velocity

Vellore Institute of Technology-Akash Porwal, Abhishek Tripathi
  • Technical Paper
  • 2020-01-0983
To be published on 2020-04-14 by SAE International in United States
Vehicle collisions are a major concern in the modern automotive industry. To ensure the passenger safety, major focus have been given on energy absorption pattern during collision, which lead to the implementation of new design of the crash box for low speed collision. The main aim of this research is optimization of the conical shaped bitubular structure based on its mean diameter, graded thickness and semi vertical angle. Further to increase energy absorption characteristics of the conical crash box, corrugations are integrated on both tubes and optimized based on different parameters such as number of corrugations, pattern of corrugation relative to both tubes and depth of corrugation. A finite element model is created to perform parametric study on corrugated conical bitubular structure based on axial and oblique load conditions at low velocity. Optimization to maximize total absorbed energy and minimize peak impact load on the crash box within constraints is conducted. The result showed that optimal design of proposed crash box performs effectively as energy absorbing structure and can be used in the future vehicle…
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Finite Element Modeling of an Energy-Absorbing Guardrail End Terminal

SAE International Journal of Commercial Vehicles

Insurance Institute for Highway Safety, USA-Wen Hu
Virginia Tech, USA-Yunzhu Meng, Costin Daniel Untaroiu
  • Journal Article
  • 02-12-04-0021
Published 2020-02-07 by SAE International in United States
Guardrail end terminals are specifically designed to decelerate vehicles during impact and protect vehicle occupants from severe injuries. The main objective of this research was to develop and validate a Finite Element (FE) model of the ET-Plus, a commonly used energy-absorbing guardrail end terminal. The ET-Plus FE model was created based on publicly available data on ET-Plus dimensions and material properties. The model was validated against the NCHRP-350 crash tests 27-30 and 31-30 by performing crash simulations with a vehicle model at 100 km/h (62 mph) pre-impact velocity. To check the model robustness, crash simulations with vehicle pre-impact velocities from 97 km/h (60 mph) to 113 km/h (70 mph) were also performed. The developed ET-Plus FE model has a high-quality mesh and can replicate the energy-absorbing mechanism. The time histories of the vehicle yaw angle predicted in the FE simulations of the two NCHRP 350 crash tests showed good agreement with the corresponding test data. Additionally, the model was stable in crash simulations with the investigated range of pre-impact velocities, and both post-impact velocities and…
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Daytime visibility aspects under alternative use of headlamps

ARTEB-Carlos Alberto Leite de Moura
PRIME ONE-Paulo Victor S. Pingueiro
  • Technical Paper
  • 2019-36-0072
Published 2020-01-13 by SAE International in United States
Daytime visibility represents one of the most important themes in automotive safety. Some accidents, especially frontal collisions, used to occur as a result of a bad recognition of vehicle presence. In order to keep vehicles more visible during the day, there is a luminous device called Daytime Running Lamp (DRL). Nowadays DRL is not mandatory in Brazil, but it will be in 2021 for new vehicles. As with any situation that involves technological transitions, some questions appear, among them: how to equalize the market, in terms of daytime visibility, considering newer and older vehicles together? How to improve visibility in older vehicles that were not designed with DRL? The answer maybe lies in the alternative usage of automotive headlamps. Among other facts, one luminous device for two functions can result in safety improvements without unexpected investments. Therefore, how can this technically be achieved? By CONTRAN 667, that has adopted North America references, including luminous devices according to FMVSS, it is possible to use a low beam or a high beam dimmed to a maximum 7000…
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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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Risk of Concussion in Low- to Moderate-Speed Frontal and Rear-End Motor Vehicle Collisions Evaluated Using Head Acceleration-Based Metrics

Exponent, Inc.-Stephanie A. Pasquesi, Alexander Bruno, Amy Courtney, Stacy M. Imler, Janine Smedley, Michael T. Prange
Published 2019-04-02 by SAE International in United States
Over the past decade, there has been an increase in awareness and concern about the occurrence and long-term effects of concussions. Traumatic brain injury (TBI)-related emergency department (ED) visits associated with motor vehicle collisions, including patients with a diagnosis of concussion or mild TBI (mTBI), have increased while deaths and hospital admissions related to TBI have decreased. The diagnostic criteria for concussion have evolved and broadened, and based on current assessments and diagnostic imaging techniques, there are often no objective findings, yet a diagnosis of concussion may still be rendered. Clinical assessment of concussion may be based only on patient-reported symptoms and history, making it difficult to objectively relate the reported increase in TBI-related ED visits due to motor vehicle collisions to specific collision parameters. This study aims to perform a scientific evaluation of concussion risk during motor vehicle collisions, strengthened by objective, quantitative data, specifically focusing on head acceleration-based metrics. Data from full-scale passenger vehicle crash tests are reported for frontal and rear-end collisions with delta-Vs ranging from 6.0 to 19.0 kph (3.7 to…
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