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Seat Design Studies

Kettering University-Santhosh Sivan Kathiresan, Raghu Echempati
  • Technical Paper
  • 2020-01-1101
To be published on 2020-04-14 by SAE International in United States
In this paper, further studies have been carried out on the analysis and effect of certain design modifications on the structural integrity of an automotive seating rail structure. Automotive seating is one of the important component in the automotive industry due to their main function to carry the weight of passenger as well as to sustain the vibrations from the road. The seat structures are assembled to carry other important components such as side airbag and seatbelt systems. The entire seating is supported firmly and attached to the bottom bodywork of the vehicle through the linkage assembly called the seat rails. Seat rails are adjustable in their longitudinal motion which plays an important role in giving the passengers enough leg room to make them feel comfortable. Therefore, seat rails under the various operating conditions such as forward and normal positions should be able to withstand the complete weight of the human and the associated loads due to vibrations. In this paper, some of the functional requirements such as strength, stiffness, durability and crash performance are…
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Evaluation of General Motors Event Data Recorder Performance in Semi-Trailer Rear Underride Collisions

Momentum Engineering Corp.-Nicholas Famiglietti, Ryan Hoang, Edward Fatzinger, Jon Landerville
  • Technical Paper
  • 2020-01-1328
To be published on 2020-04-14 by SAE International in United States
The objective of this study was to analyze the validity of airbag control module data in semi-trailer rear underride collisions. These impacts involve unusual collision dynamics, including long crash pulses and minimal bumper engagement [1]. For this study, publicly available data from 16 semi-trailer underride guard crash tests performed by the Insurance Institute for Highway Safety (IIHS) were used to form conclusions about the accuracy of General Motors airbag control module (ACM) delta-V (ΔV) data in a semi-trailer rear underride scenario. These tests all utilized a 2009 or 2010 Chevrolet Malibu impacting a stationary 48’ or 53’ semi-trailer at a speed of 35 mph. Nine tests were fully overlapped collisions, six were 30% overlapped, and one was 50% overlapped [2]. The IIHS test vehicles were equipped with calibrated 10000 Hz accelerometer units. Event Data Recorder (EDR) data imaged post-accident from the test vehicles were compared to the reference IIHS data. For each test, root mean square error (RMSE), the percent error over time, and the difference between the EDR ΔV and the IIHS ΔV, was…
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Multi-objective Restraint System Robust and Reliability Design Optimization with Advanced Data Analytics

ESTECO North America-Zhendan Xue
Ford Motor Company-Guosong Li, Kevin Pline, Zhenyan Gao
  • Technical Paper
  • 2020-01-0743
To be published on 2020-04-14 by SAE International in United States
Vehicle restraint system design optimization is important for occupant protection and achieving high score in NCAP rating of five-Star. The target is to minimize the Relative Risk Score (RRS), defined by the National Highway Traffic Safety Administration (NTHSA)'s New Car Assessment Program (NCAP). The design input includes restraint feature options (e.g., some specific features on/off) as discrete design variables, as well as continuous restraint design variables, such as airbag firing time, airbag vent size, inflator power level, etc. The optimization problem is constrained by injury criteria involve HIC, chest deflection/acceleration, neck tension/compression, etc., which ensures the vehicle meeting or exceeding all Federal Motor Vehicle Safety Standard (FMVSS) No. 208 requirements. Considering the local variability of input variables such as manufacturing tolerances, the robustness and reliability of nominal designs were also taken into account in optimization process. Genetic Algorithms (GA) based optimization methods were applied because these methods can handle discrete and continuous design variables simultaneously, as well treat such highly nonlinear optimization problems in a robust manner In this study, frontal impact modes were used…
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Evaluation of Laminated Side Glazing and Curtain Airbags for Occupant Containment in Rollover

Exponent Inc.-Bruce Miller, Janine Smedley, Michael Carhart, Sarah Sharpe
Ford Motor Company-Ram Krishnaswami
  • Technical Paper
  • 2020-01-0976
To be published on 2020-04-14 by SAE International in United States
By their nature as chaotic, high-energy events, rollovers pose an injury risk to occupants, in particular through exposure to perimeter contact and ejection. While seatbelts have long been accepted as a highly effective means of retaining occupants, it has been suggested that technologies such as laminated safety glazing or rollover curtain airbags could alternatively provide effective occupant containment during rollovers. In this study, a full-scale dolly rollover crash test was performed to assess the occupant containment capacity of laminated side glazing and rollover curtain airbags in a high-severity rollover. This allowed for the analysis of unrestrained occupant kinematics during interaction with laminated side glazing and rollover curtain airbags and evaluation of failure modes and limitations of laminated glazing and rollover curtain airbags as they relate to partial and complete ejection of unrestrained occupants. The dolly rollover was performed with a 2010 Chevrolet Express at a nominal speed of 43 mph, with unbelted anthropomorphic test devices (ATDs) positioned in the driver, right front passenger, and designated third, fourth, and fifth row seating positions. Vehicle dynamics and…
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Evaluation of Corpuscular Particle Method (CPM) in LS-DYNA for airbag modeling

FCA US LLC-Neeharika Anantharaju, Kalu Uduma, Yibing Shi
  • Technical Paper
  • 2020-01-0978
To be published on 2020-04-14 by SAE International in United States
This paper presents a systematic study performed to assess the maturity of Corpuscular Particle Method (CPM) to accurately predict airbag deployment kinematics and its overall responses. The critical phases of the study involved, firstly, an assessment of correlation of CPM predicted inflator characteristics to closed tank tests. Secondly, a correlation assessment of CPM for deployment characteristics, airbag pressure and reaction force for a static deployment test of a Driver Airbag (DAB). Lastly, the impactor force predicted by CPM was correlated against physical drop tower tests. All these studies were repeated using traditionally used Uniform Pressure Method (UPM), to compare the numerical methods for their accuracy in predicting the physical test, computational cost, and applicability. The results from these studies suggest that CPM satisfies the fundamental energy laws, and accurately captures the realistic airbag deployment kinematics, especially during the early deployment, unlike UPM. For a fully deployed DAB, the airbag pressure, reaction force, and the impactor force are accurately predicted by both CPM and UPM. Additionally, the computational cost of CPM was observed to be on…
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Accident Statistical Distributions from NASS CDS - An Update

Exponent Inc.-Jennifer L. Yaek, Thomas Brown
SURVICE Engineering Co.-Alan Goertz
  • Technical Paper
  • 2020-01-0518
To be published on 2020-04-14 by SAE International in United States
The National Automotive Sampling System (NASS) Crashworthiness Data System (CDS) contains an abundance of field accident data. As technology advances and the database continues to grow over the years, the statistical significance of the data increases and trends can be observed. The purpose of this paper is to provide a comprehensive, up-to-date, reference resource with respect to commonly sought-after accident statistics. Charts include up-to-date accident distributions by Delta-V and impact direction with corresponding injury severity rates. Rollover data is also analyzed, as well as historical trends for injury severity, belt usage, air bag availability, and vehicle safety technology availablility.
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Responses of the THOR in Oblique Sled Impacts: Focus on Chest Deflection

Ford Motor Company-Raed E. El-Jawahri, Kevin Siasoco, Rich Ruthinowski, Robert W. McCoy, Zhenyan Gao, Dean Jaradi
  • Technical Paper
  • 2020-01-0522
To be published on 2020-04-14 by SAE International in United States
The National Highway Traffic Safety Administration (NHTSA) published a Request for Comments (RFC) on proposed changes to the New Car Assessment Program (NCAP) in December of 2015. One potential change was the introduction of a frontal Oblique Impact (OI) crash test. The Test device for Human Occupant Restraint (THOR) in the front left seat was used in the proposed OI test. In the current study, eleven oblique sled impact tests were conducted. The environment was representative of a generic mid-sized sedan. The buck was mounted on a rigid plate that allowed the pre-test rotation of the buck relative to the sled axis. A generic mid-sized OI pulse was used. The pulse was applied in the longitudinal direction of the sled. The THOR was seated in the driver seat and was restrained with a 3-point belt, a driver airbag (DAB) and a knee airbag (KAB). The belt had a 4-2.5 kN digressive shoulder load limit (LL), a retractor pre-tensioner (RPT) and an anchor pre-tensioner (APT). Out of the four IR-TRACC locations, the upper right (UR) yielded…
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Further Non-Deployment and Deployment Laboratory Experiments Using a Toyota Auris 2007 Event Data Recorder

University of Malta-Miguel Tabone, Mario Farrugia
  • Technical Paper
  • 2020-01-1329
To be published on 2020-04-14 by SAE International in United States
The experimental campaign discussed in publication 2019-01-0635 was extended to emulate more vehicle parameters and also to increase severity leading to deployment event. The engine RPM and Accelerator Pedal Position (APP) where emulated using LabVIEW and added to the previously reported emulated parameters of wheel speeds and brake status. The engine RPM and APP where made to follow realistic increases and decreases so that the pre-crash data was representative of the associated wheel speeds and brake status. Overlapping non deployments events were generated and the EDR data is presented enriched with additional (faster) CAN bus data sniffed from the vehicle harness. The differences in values from EDR and CAN bus data are noted and discussed. While the non-deployment events were still generated using the rubber mallet in pendulum configuration as in 2019-01-0635, a series of tests were performed using an Izod pendulum to incrementally increase event severity until deployment event was generated. The Izod pendulum was instrumented with a rotational potentiometer to measure its instantaneous angle while laboratory accelerometers were used to separately measure acceleration.…
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Evaluating the Accuracy of Speed Change Data Downloaded from Airbag Systems After Offset and Oblique Crash Tests

MEA Forensic Engineers & Scientists-Jean-Loup Curtat, Craig Wilkinson, Gunter P. Siegmund
  • Technical Paper
  • 2020-01-1327
To be published on 2020-04-14 by SAE International in United States
Data downloaded from event data recorders (EDRs) integrated into the airbag systems of passenger vehicles can be key evidence for collision investigators. Often the data includes information about the severity of the collision in terms of the longitudinal and lateral speed change experienced by the vehicle. Previous studies have shown that for collisions with small lateral speed changes, the accuracy of the reported longitudinal speed change varies with manufacturer and magnitude. The goal of this study was to quantify the accuracy of EDR speed changes in high-speed angled collisions. The reports of twenty-five crash tests in the National Highway Traffic Safety Administration’s Frontal Oblique Offset Testing Program include data from on-board accelerometers as well as data downloaded from EDRs. The accuracy of the EDR speed change was evaluated by calculating the relative error with the longitudinal and lateral speed changes calculated from the on-board accelerometers. The error ranged from 0 % to 20 % for the reported longitudinal speed change and from 3 % to 41 % for lateral speed change, with an outlier test…
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A primary 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 postures in the self-driving car, there is a new and major challenge for occupant protection. In particular, the studies on occupant restraint systems used in the self-driving car has significantly delayed compared to the development of the autonomous technologies. In this paper, a numerical study was conducted to investigate the protective effects of the mainstream restraint systems (3-points belt with airbag or 4-points belt with airbag) on the driver in three different scenarios (driving with a seat angle of 110°, half-reclining resting with a seat angle of 135°, and reclining resting with a seat angle of 160°) . It can be found that in the simulation results: 1. All the restraint systems are capable of providing effective protection for the driving driver and the restraint system with 4-points belt has advantages due to its better protective effect on the occupant thorax; 2. When the driver is half-reclining or reclining resting, the head HIC36, neck Nij and chest compression are about 827-958, 0.62-0.88, and 66-68 mm, respectively;…