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Analysis of occupant dynamics and optimization of Driver airbag performance against all FMVSS208 frontal impact cases using validated Finite element Methodology

Key Safety Systems Inc.-Sumit Sharma
  • Technical Paper
  • 2019-28-2545
To be published on 2019-11-21 by SAE International in United States
Several people die every year due to vehicle accidents. Federal Motor Vehicle Safety Standards (FMVSS) are U.S. federal regulations stating design, structure, performance, and durability necessities for vehicles. The objective of a crash test for FMVSS No. 208 is to measure how well a passenger vehicle would protect its occupants in the event of a frontal crash. FMVSS 208 consists of series of tests including different impact surface type as well as occupant sizes. It also covers the belted and unbelted occupant behavior at the time of front impact. Each test scenario has different ways to injure the occupant. Airbags are the part of passive safety equipment family in any automobile and play an imperative role to reduce the occupant head and chest injuries at the time of crash or accidents. This study covers the evaluation of airbag performance in all FMVSS 208 load cases using validated Finite Element Methodology (FEM). Finite Element Analysis (FAE) is an advanced tool to simulate the airbag behavior. Airbag deployment phenomena is very complex in nature and depend on…
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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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Evaluation of Occupant Kinematics in Low- to Moderate-Speed Frontal and Rear-End Motor Vehicle Collisions

Exponent Inc.-Alexander Bruno, Megan Toney-Bolger, Juff George, Jeffrey Koller, Anton Filatov, Joseph Olberding
Published 2019-04-02 by SAE International in United States
Low- to moderate-speed motor vehicle collisions are a common crash type and are sometimes associated with injury complaints. Understanding occupant motion (kinematics) in response to low- and moderate-speed motor vehicle collisions is important for evaluating occupant interactions with interior vehicle structures, including the restraint systems, with the ultimate goal of assessing injury potential. Furthermore, quantitative occupant kinematic data from full-scale crash testing of late-model passenger vehicles is limited for collisions at low- to moderate-speeds. The current study reports kinematic data from full-scale frontal and rear-end crash tests of late-model, mid-size sedans with delta-Vs ranging from 6.0 to 19.0 kph (3.7 to 11.8 mph) and 5.6 to 19.5 kph (3.5 to 12.1 mph), respectively. For each test vehicle, the motion of a Hybrid III 50th-percentile male anthropomorphic test device (ATD) restrained in the driver seat was recorded using high-speed onboard video. Motion tracking of the video was used to evaluate the excursion and velocity of each ATD’s head, shoulder, elbow, and knee with respect to the vehicle interior. Restraint loads were recorded via load cells placed…
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Innovative Knee Airbag (KAB) Concept for Small Overlap and Oblique Frontal Impacts

Detroit Engineered Products (DEP) Inc.-Rahul Makwana
Ford Motor Co., Ltd.-Pardeep Jindal
Published 2019-04-02 by SAE International in United States
Considerable research has been conducted in terms of attempting to reduce lower leg injury risk in full frontal impacts, in some cases by the use of a knee airbag (KAB). However, there has been limited research into the performance of KAB systems during a crash test with increased oblique loading, such as the IIHS small overlap frontal test, an oblique moving deformable barrier test (OI) being researched by NHTSA, and a mobile progressive deformable barrier test (MPDB) that is expected to be implemented by Euro NCAP in the next few years. The objective of the current numerical study was concentrated on the evaluation of an innovative KAB concept design intended to reduce ATD right inboard lower leg/foot responses under small overlap and oblique loading conditions. A novel appendage KAB concept design was developed with the help of morphing and computational studies which were performed with different ATD sizes. In the study, one of the lower leg/foot responses was monitored and compared over a conventional KAB design. Cases investigated in the study showed that the novel…
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Estimation of the Relative Roles of Belt-Wearing Rate, Crash Speed Change, and Several Occupant Variables in Frontal Impacts for Two Levels of Injury

Ford Motor Company-Tony Laituri, Scott Henry, Guosong Li
Published 2019-04-02 by SAE International in United States
Driver injury probabilities in real-world frontal crashes were statistically modeled to estimate the relative roles of five variables of topical interest. One variable pertained to behavior (belt-wearing rate), one pertained to crash circumstances (speed change), and three pertained to occupant demographics (sex, age, and body mass index). The attendant analysis was composed of two parts: (1) baseline statistical modeling to help recover the past, and (2) sensitivity analyses to help consider the future.In Part 1, risk functions were generated from statistical analysis of real-world data pertaining to 1998-2014 model-year light passenger cars/trucks in 11-1 o’clock, full-engagement frontal crashes documented in the National Automotive Sampling System (NASS, 1997-2014). The selected data yielded a weighted estimate of 1,269,178 crash-involved drivers. Those data were parsed for four subpopulations: two levels of belt use (properly-belted vs. unbelted) and two levels of driver injury (moderate-to-maximum, MAIS2+ vs. serious-to-maximum, MAIS3+). For each subpopulation, a baseline statistical model was generated via logistic regression, cast as a function of the studied variables. Each risk function was assessed for statistical significance (p-value for each…
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Posterior Cruciate Ligament Response to Proximal Tibia Impact

Biomechanics Research Associates-Bruce Donnelly
NHTSA-Joe McFadden
Published 2019-04-02 by SAE International in United States
Posterior cruciate ligament (PCL) injuries, although rarely life threatening, affect the quality of life of the person who sustains the injury. The PCL is the primary restraint to posterior tibial translation and can be injured when the tibia moves posteriorly relative to the femur. This type of injury is common in frontal crashes where the tibia may impact the dashboard or steering column. To quantify what happens during dynamic loading of the tibial plateau, isolated cadaveric lower limbs (n = 14) were impacted at dynamic rates with a linear pneumatic ram. During the testing, a static load was applied to the quadriceps tendon to simulate active musculature. Forces as well as the stretch of the PCL were measured. The most common injuries were tibia fractures and PCL tears. The stiffness for the tests at impact velocities of 1.4 and 2.9 m/s were on average 120 N/mm and 141N/mm, respectively. A trend towards increasing femur force with increasing velocity was found. The study presents biofidelity targets for the response of the cadaveric limbs, which can be…
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Multi-Material Topology Optimization for Crashworthiness Using Hybrid Cellular Automata

General Motors-Chandan Mozumder, Simon Xu
Indiana University; Purdue University-Prasad Tapkir, Andres Tovar
Published 2019-04-02 by SAE International in United States
Structures with multiple materials have now become one of the perceived necessities for automotive industry to address vehicle design requirements such as light-weight, safety, and cost. The objective of this study is to develop a design methodology for multi-material structures accountable for vehicle crash durability. The heuristic topology synthesis approach of Hybrid Cellular Automaton (HCA) framework is implemented to generate multi-material structures with the constraint on the volume fraction of the final design. The HCA framework is integrated with ordered-SIMP (solid isotropic material with penalization) interpolation, artificial material library, as well as statistical analysis of material distribution data to ensure a smooth transition between multiple practical materials during the topology synthesis. Since the proposed method does not rely on additional variables to represent material selection, the computational cost of this method is independent of the number of the phases in a multi-material design. The dynamic simulations of a sphere ball impacting an armor plate and the frontal crash on a car bumper are used to evaluate the proposed multi-material topology synthesis algorithm. The practical materials…
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Head and Neck Loading Conditions over a Decade of IIHS Rear Impact Seat Testing

Exponent Inc.-John M. Scanlon, Jessica Isaacs, Christina Garman
Published 2019-04-02 by SAE International in United States
Rear-end impacts are the most common crash scenario in the United States. Although automated vehicle (AV) technologies, such as frontal crash warning (FCW) and automatic emergency braking (AEB), are mitigating and preventing rear-end impacts, the technology is only gradually being introduced and currently has only limited effectiveness. Accordingly, there is a need to evaluate the current state of passive safety technologies, including the performance of seatbacks and head restraints. The objective of this study was to examine trends in head and neck loading during rear impact testing in new vehicle models over the prior decade. Data from 601 simulated rear impact sled tests (model years 2004 to 2018) conducted as a part of the Insurance Institute for Highway Safety (IIHS) Vehicle Seat/Head Restraint Evaluation Protocol were obtained. This dynamic evaluation involves a simulated rear-end crash using a Biofidelic Rear Impact (BioRID IIg) ATD positioned in the seat attached to a crash simulation sled and accelerated to represent a rear crash with a delta-V of approximately 15.6 kph (15.6 ± 0.26 kph). Head and neck injury…
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Design and Optimization of Crash-Box of Passenger Vehicle to Enhance Energy Absorption

ARAI Academy-Shreyas Sarage
Automotive Research Association of India-Mohammad Rafiq B. Agrewale, K.C. Vora
Published 2019-03-25 by SAE International in United States
Frontal crash is the most common type of accidents in passenger vehicles which results in severe injuries or fatalities. During frontal crash, some frontal vehicle body has plastic deformation and absorbs impact energy. Hence vehicle crashworthiness is important consideration for safety aspect. The crash box is one of the most important parts in vehicle frontal structure assembly which absorb crash energy during impact. In case of frontal crash accident, crash box is expected to be collapsed by absorbing crash energy prior to the other parts so that the damage to the main cabin frame and occupant injury can be minimized. The main objective of this work is to design and optimize the crash box of passenger vehicle to enhance energy absorption. The modeling of the crash box is done in CATIA V5 and simulations are carried out by using ANSYS. The results show significant improvement in the energy absorption with new design of the crash box and it is validated experimentally on UTM. Further numerical analysis of bumper beam assembly is performed with consideration of…
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Computational and Experimental Analysis of Head Injury Criteria (HIC) in Frontal Collision of Car with Pedestrian

Rajarambapu Institute of Technology-Dr. Dhananjay G Thombare
Published 2019-01-09 by SAE International in United States
Road accident between pedestrian and motor vehicle causes severe injuries and even death of pedestrian. The accident statistics show that the possibility of injury to pedestrian is higher in case of collision with car on busy roads. In car and pedestrian collisions, the pedestrian’s head hits with car bonnet and suffer from multiple injuries such as skull fractures and brain injury. The role of car bonnet structural strength plays an important role in pedestrian head injury level. To provide enough structural strength the high bonnet thickness is provided with under bonnet stiffeners, however thick bonnet and stiffeners reduces deformation of the bonnet during collision and increases injury level to pedestrian. Hence optimum bonnet thickness, least number and geometry of stiffeners and enough structural strength is important for bonnet to reduce injury level. The aim of this study is to analyse the effect of car bonnet thickness, number and arrangement of under bonnet stiffeners on head injury levels with the help of head injury criteria (HIC). Head Injury Criteria (HIC) is a measure of the likelihood…
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