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The Navigator

Autonomous Vehicle Engineering: May 2019

Sam Abuelsamid
  • Magazine Article
  • 19AVEP05_03
Published 2019-05-01 by SAE International in United States

Lessons from the 737 Max-8 Debacle

It's always a tragedy when people die as a result of a machine malfunctioning. It's even more tragic if we fail to learn from that failure to make future machines safer.

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Eyes In the Sky

Aerospace & Defense Technology: May 2019

  • Magazine Article
  • 19AERP05_04
Published 2019-05-01 by SAE International in United States

For Drones, Combining Vision Sensor and IMU Data Leads to More Robust Pose Estimation

Drones (i.e. quadrotors) are a popular and increasingly wide-spread product used by consumers as well as in a diversity of industrial, military and other applications. Historically under the control of human operators on the ground, they're becoming increasingly autonomous as the cameras built into them find use not only for capturing footage of the world around them but also in understanding and responding to their surroundings. Combining imaging with other sensing modalities can further bolster the robustness of this autonomy.

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Stapp Car Crash Journal Vol. 62, 2018

  • Book
  • B-STAPP2018
Published 2019-04-30 by The Stapp Association in United States
This title includes the technical papers developed for the 2018 Stapp Car Crash Conference, the premier forum for the presentation of research in impact biomechanics, human injury tolerance, and related fields, advancing the knowledge of land-vehicle crash injury protection. The conference provides an opportunity to participate in open discussion about the causes and mechanisms of injury, experimental methods and tools for use in impact biomechanics research, and the development of new concepts for reducing injuries and fatalities in automobile crashes. The topics covered this year include: • Effect of restraints on chest deflection • Thoracic response in dynamic front loading • Side impact assessments and comparisons • Front airbag deployment rates and implications • Reanalysis of experimental brain strain data • Modeling pedestrian impacts • Short communications o New data on the biomechanics of injury and human tolerance, new methods and tools to study the biomechanics of injury, new developments in occupant protection systems, and new concepts on the biomechanics of injury based on experimental and analytical studies.
 

Constructing a Concept Vehicle Structure Optimized for Crashworthiness

Dassault Systemes Simulia Corp.-Yangwook Choi, Shawn Freeman, Fabien Letailleur
Published 2019-04-02 by SAE International in United States
Multi-disciplinary optimization (MDO) of a vehicle structure at the earliest stages of design is critical as OEMs are pressed to reduce the design time in order to respond to various demands from the market. MDO for the three essential areas of performance of the vehicle structure (NVH, Crash, and Durability) needs the throughput for each of the major disciplines to be approximately in the same range of turn-around time. However, crashworthiness simulation typically takes significantly longer than the others, making it difficult to include crashworthiness in the MDO. There have been many approaches to address crash simulation in a shorter time. The lumped mass-spring method is one of the approaches but has not been widely accepted since there are many difficulties in modeling and replicating the existing structure. It required physical or Finite Element tests for all structural components to get the spring properties, and then it is hard to convert the optimized spring properties into the real design of the structural components. In this paper, a reversed workflow is presented to construct the structure…
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Development of Subject-Specific Elderly Female Finite Element Models for Vehicle Safety

Chongqing University-Yunlei Yin, Junming Li, Qingmiao Wang
State Key Lab of Veh NVH & Safety Technology/Chongqing Univ-Wenxiang Dong, Zhenfei Zhan
Published 2019-04-02 by SAE International in United States
Previous study suggested that female, thin, obese, and older occupants had a higher risk of death and serious injury in motor vehicle crashes. Human body finite element models were a valuable tool in the study of injury biomechanics. The mesh deformation method based on radial basis function(RBF) was an attractive alternative for morphing baseline model to target models. Generally, when a complex model contained many elements and nodes, it was impossible to use all surface nodes as landmarks in RBF interpolation process, due to its prohibitive computational cost. To improve the efficiency, the current technique was to averagely select a set of nodes as landmarks from all surface nodes. In fact, the location and the number of selected landmarks had an important effect on the accuracy of mesh deformation. Hence, how to select important nodes as landmarks was a significant issue. In the paper, an efficient peak point-selection RBF mesh deformation method was used to select landmarks. The multiple peak points were selected to expand landmarks set, so as to improve the morphing quality compared…
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Using Adjusted Force-Displacement Data to Predict the EBS of Car into Barrier Impacts

MEA Forensic Engineers & Scientists-Russell Gish, Ross Hunter, Ryan Fix, Kodiak Brush
Published 2019-04-02 by SAE International in United States
Our goal was to evaluate whether modifications to the force-displacement curves derived from a high-speed NHTSA frontal barrier test could be used to improve predictions of the equivalent barrier speed of a low-speed crash involving the same vehicle. Using an earlier iteration of the technique described here, Hunter et al. [2] showed that the F-D curves from higher-speed tests over-predicted the EBS of lower-speed tests by 21±17%. After modifying the earlier technique to account for powertrain stack-up and barrier force attenuation prior to reaching peak dynamic crush, the technique evaluated here reduced this error to 1% with a standard deviation that varied between ±9% and ±13% depending on which engine accelerometers were chosen for the adjustment. These findings suggest that the method and modifications proposed here can be used to reconstruct car crashes provided that there is a relationship between dynamic crush and residual crush. Of the 158 NHTSA tests used in this study, only seven of the crash tests reported residual crush measured to the bumper beam. These seven data points indicate the average…
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Structural Optimization of Thin-Walled Tubular Structures for Progressive Collapse Using Hybrid Cellular Automaton with a Prescribed Response Field

Indiana University-Purdue University Indianapolis-Andres Tovar
Purdue University-Homero Valladares, Joel Najmon
Published 2019-04-02 by SAE International in United States
The design optimization of thin-walled tubular structures is of relevance in the automotive industry due to their low cost, ease of manufacturing and installation, and high-energy absorption efficiency. This study presents a methodology to design thin-walled tubular structures for crashworthiness applications. During an impact, thin-walled tubular structures may exhibit progressive collapse/buckling, global collapse/buckling, or mixed collapse/buckling. From a crashworthiness standpoint, the most desirable collapse mode is progressive collapse due to its high-energy absorption efficiency, stable deformation, and low peak crush force (PCF). In the automotive industry, thin-walled components have complex structural geometries. These complexities and the several loading conditions present in a crash reduce the possibility of progressive collapse. The Hybrid Cellular Automata (HCA) method has shown to be an efficient continuum-based approach in crashworthiness design. All the current implementations of the HCA method use a scalar set point to design structures with a uniform distribution of a field variable, e.g., stress, strain, internal energy density (IED), mutual potential energy. For example, using IED and mutual potential energy as the field variable result in high…
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Has Electronic Stability Control Reduced Rollover Crashes?

Toyota Motor Corp.-Rini Sherony
Virginia Tech-Luke Riexinger, Hampton Gabler
Published 2019-04-02 by SAE International in United States
Vehicle rollovers are one of the more severe crash modes in the US - accounting for 32% of all passenger vehicle occupant fatalities annually. One design enhancement to help prevent rollovers is Electronic Stability Control (ESC) which can reduce loss of control and thus has great promise to enhance vehicle safety. The objectives of this research were (1) to estimate the effectiveness of ESC in reducing the number of rollover crashes and (2) to identify cases in which ESC did not prevent the rollover to potentially advance additional ESC development.All passenger vehicles and light trucks and vans that experienced a rollover from 2006 to 2015 in the National Automotive Sampling System Crashworthiness Database System (NASS/CDS) were analyzed. Each rollover was assigned a crash scenario based on the crash type, pre-crash maneuver, and pre-crash events. The Insurance Institute for Highway Safety ESC availability database was matched to each NASS/CDS case vehicle by the vehicle make, model, and model year. ESC effectiveness was computed using the quasi-induced exposure method.From 2006-2015, control loss was a factor in 29.7%…
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Influence of DISH, Ankylosis, Spondylosis and Osteophytes on Serious-to-Fatal Spinal Fractures and Cord Injury in Rear Impacts

Collision Research & Analysis Inc.-Samuel White
ProBiomechanics LLC-David Viano, Chantal Parenteau
Published 2019-04-02 by SAE International in United States
Seats have become stronger over the past two decades and remain more upright in rear impacts. While head restraints are higher and more forward providing support for the head and neck, serious-to-fatal injuries to the thoracic and cervical spine have been seen in occupants with spinal disorders, such as DISH (diffuse idiopathic skeletal hyperostosis), ankylosis, spondylosis and/or osteophytes that ossify the joints in the spine. This case study addresses the influence of spinal disorders on fracture-dislocation and spinal cord injury in rear impacts with relatively upright seats. Nineteen field accidents were investigated where serious-to-fatal injuries of the thoracic and cervical spine occurred with the seat remaining upright or slightly reclined. The occupants were lap-shoulder belted, some with belt pretensioning and cinching latch plate. The occupants were older and had pre-existing disorders of the spine, including DISH, ankylosis, spondylosis and/or osteophytes that ossify the spinal joints. The crashes were summarized and the mechanism for injury was analyzed. The 19 cases involved fracture-dislocation and spinal cord injury at areas of the spine where DISH, ankylosis, spondylosis and/or…
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VirtualCrash.com - Occupant Crash Simulation Analysis Made Easy

Hork Enterprises-Henk Helleman
Published 2019-04-02 by SAE International in United States
Over 30 years of occupant crash safety simulations have seen ever more sophisticated tools and models to keep pace with ever more demanding and expanding requirements. These sophisticated tools, however, require highly trained and experienced analysis specialists to operate. This keeps them out of reach of occasional users such as program managers, restraints buyers, and design engineers. Yet, the people involved in the early stages of vehicle development can have a great impact on vehicle safety performance and the costs of achieving the targets. By combining prebuilt models and a fully capable finite element solver with an easy to use web interface, we aim to make the simulation technology available to anybody with a web browser.The Virtualcrash.com application is richly featured. Alike to sled testing, there is a choice of multiple vehicle geometries, from sub-compacts to large trucks. They come with crash pulses that are typical for their class that may be scaled up or down to make them more or less severe. If that does not suit the purpose, a custom crash pulse may…
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