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A Machine Learning based Multi-objective Multidisciplinary Design Optimization (MMDO) for Lightweighting the Automotive Structures

Mahindra and Mahindra-Ranga Srinivas Gunti
  • Technical Paper
  • 2019-28-2424
To be published on 2019-11-21 by SAE International in United States
The present work involves Machine Learning (ML) based Multi-objective Multidisciplinary Design Optimization (MMDO) for lightweighting the automotive structures. The challenge in deployment of MMDO algorithms in solving real-world automotive structural design problems is the enormous time involved in solving full vehicle finite element models that involve large number of design variables and multiple performance constraints pertaining to vehicle dynamics, durability, crash and NVH domains. With the availability of powerful workstations and using the advanced Computer Aided Engineering (CAE) tools, it has become possible to generate huge sets of simulation data pertaining to multiple domains. In the present work, lightweigting of the vehicle structure is achieved, considered the vehicular hardpoint locations and the gages of the vehicle structures as the design variables and performance parameters pertaining to vehicle dynamics, structural durability, front-end intrusions during an IIHS offset impact test and the modal frequencies of few critical structural members as the constraint variables. Artificial Neural Networks (ANN) based algorithms were used for developing the predictive models of various performance parameters. The predictive models were then used to…
 

Load Distribution Optimization of seatbelts using validated finite element approach.

anshul satija-Anshul Satija
  • Technical Paper
  • 2019-28-2575
To be published on 2019-11-21 by SAE International in United States
The seat belt system is one of most imperative component of the safety instrument family in a vehicle. The main purpose of seat belt is to minimize the injuries by preventing the occupant from impacting hard interior parts of the vehicle and also the passenger from being thrown-out from the vehicle in case of rollover accidents. The standard three-point belts, mounted to the vehicle in three places, namely anchor, D ring and buckle. The position of D ring is very important to distribute the impact load evenly to the occupants. Very high load in any of these locations could cause breakage of the mountings and also concentrated loading on the occupant chest of pelvis. This study mainly focuses on the seatbelt assembly performance improvement against ECE-R16 sled test. The sled test was carried out first using 28g peak acceleration pulse and measurement of forces at shoulder and anchor position was measured using the load cell. FE (Finite Element) model of the complete seatbelt assemble was developed including buckle, retractor and anchor plate. The simulation was…
 

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…
 

SIMULATION OF SOFTENING AND RUPTURE IN MULTILAYERED FUEL TANK MATERIAL

General Motors Technical Center India-Vijaya Kumar R L, Biswajit Tripathy, Jayaraj Radhakrishnan
  • Technical Paper
  • 2019-28-2557
To be published on 2019-11-21 by SAE International in United States
Research and/or Engineering Questions/Objective Plastic automotive fuel tanks made up of blow molded, multi-layered, high-density polyethylene (HDPE) material can take complex shapes with varying thickness. Accidental drop of fuel tank from a height during handling can lead to development of cracks. Damage can also occur due to an impact during a crash. This can be catastrophic due to flammability of the fuel. The objective of this work is to characterize and develop a failure model for the fuel tank material to simulate damage and enhance predictive capability of CAE for chassis and safety load cases. Methodology Different aspects were considered to develop a characterization and modelling strategy for the HDPE fuel tank. Material properties can be influenced by factors such as, service temperature, rate of deformation, state of stress etc. Hence, samples cut-out from different regions of the fuel tank were subjected to a variety of tests such as tensile test at different strain rates viz. 0.01/s, 0.1/s, 1/s, 10/s and 100/s, compression, shear, flexure and instrumented dart impact tests at different temperatures, -40°C, 23°C…
 
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Eleven Instrumented Motorcycle Crash Tests and Development of Updated Motorcycle Impact-Speed Equations

SAE International Journal of Transportation Safety

Axiom Forensic, United States-Louis Peck
Collision Engineering Associates, Inc., United States-Charles Dickerson
  • Journal Article
  • 09-07-01-0004
Published 2019-08-19 by SAE International in United States
Eleven instrumented crash tests were performed as part of the 2016 World Reconstruction Exposition (WREX2016), using seven Harley-Davidson motorcycles and three automobiles. For all tests, the automobile was stationary while the motorcycle was delivered into the vehicle, while upright with tires rolling, at varying speeds. Seven tests were performed at speeds between 30 and 46 mph while four low-speed tests were performed to establish the onset of permanent motorcycle deformation. Data from these tests, and other published testing, was analyzed using previously published equations to determine their accuracy when predicting the impact speed of Harley-Davidson motorcycles. The most accurate model was the Modified Eubanks set of equations introduced in 2009, producing errors with an average of 0.4 mph and a standard deviation (SD) of 4.8 mph. An updated set of Eubanks-style equations were developed adding data published since 2009, and further partitioning from two equations (pillars/axles and doors/fenders) to four equations (axles, pillars/bumpers, doors, and fenders). When applied to the subject tests, the newly developed set of equations produced an average error of 3.5 mph…
 

Next Steps for the IIHS Side Crashworthiness Evaluation Program

Insurance Institute for Highway Safety (IIHS)-Raul A. Arbelaez, Becky C. Mueller, Matthew L. Brumbelow, Eric R. Teoh
Published 2019-07-08 by The Stapp Association in United States
Abstract - IIHS has been conducting side impact crash tests since 2003. To understand how the side crashworthiness program can be enhanced, an ongoing research effort is focused on understanding the correlation between IIHS ratings and driver death rate. In addition, the performance of good-rated late-model vehicles has been assessed in higher severity side crash tests. The purpose of this short communication is to summarize the ongoing work and potential next steps toward developing a new crash test procedure or updating ratings criteria to further advance side crashworthiness.
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Development of a Hailstone Substitute for Representative Impact Tests

THIOT INGENIERIE-Paul Deconinck
Published 2019-06-10 by SAE International in United States
The present work started with the analysis of real hailstones collected during a storm in France. The microstructure of real hailstone was studied in order to highlight its composition and crystallographic orientations. It helped understanding the formation and the growing mechanisms of hail in the atmosphere. Its impact behaviour was then studied through two different impact experiments: ballistic impacts on rigid target and on deformable targets. It was then compared with the impact response of standard reference ices (manufactured following ASTM standard and with standard freezing) on the same impact setup. From these observations several ices (with different microstructures) were developed and also tested, in order to select the best candidate to simulated the real hailstone. The behaviour of these ices was also studied with quasi-static tension and compression test, and dynamic compression test on Split Hopkinson bar apparatus. A numerical model and an equation of state were developed in LS-Dyna finite element commercial code. At the end, this study that combines multidisciplinary and joint study between microstructure analysis, numerical modelling and experiments, helped to…
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Standard for Safety Glazing Materials for Glazing Motor Vehicles and Motor Vehicle Equipment Operating on Land Highways - Safety Standard

Glazing Materials Standards Committee
  • Ground Vehicle Standard
  • J3097Z26_201905
  • Current
Published 2019-05-28 by SAE International in United States
Specifications, test methods, and usage provisions for safety glazing materials used for glazing of motor vehicles and motor vehicle equipment operating on land highways.
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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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Research on the Model of Safety Boundary Condition Based on Vehicle Intersection Conflict and Collision

Tongji University-Biao Wu, Xichan Zhu, Maozhu Liao, Rui Liu
Published 2019-04-02 by SAE International in United States
Because of the high frequency and serious consequences of traffic accidents in the intersection area, it is of great significance to study the vehicle conflict and collision scenarios of the intersection area. Due to few actual crash accidents occurring in naturalistic driving studies data or field operational tests data, the data of traffic accident database should be also used to analyze the intersection conflict and collision. According to the China Field Operation Test (China-FOT) database and the China in Depth Accident Study (CIDAS) database, the distribution feature of the respective intersection scenario type is obtained from the data analysis. Based on the intersection scenario type, two characters of intersection conflict and collision, the environmental character and the vehicle dynamic character, are used to analyze for the integration process of intersection conflict and collision. The environmental character contains several parameters, including environment type, weather and time, which has a strong influence on the collision accidents. Through the environmental parameters analyzing, the distribution model of environmental character is obtained. The vehicle dynamic character includes two vehicle dynamic…
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