Browse Topic: Passive restraint systems

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Glossary - Automatic Belt TensionerJ2198_202109 (Current)9/10/2021
This glossary was written to provide a consistent and uniform definition of terms used in describing an automatic belt tensioner as it applies to an automotive accessory drive system.
Belt Drive (Automotive) Systems Committee
Evaluation of General Motors Event Data Recorder Performance in Semi-Trailer Rear Underride Collisions2020-01-13284/14/2020
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 quantified, plotted, and related to crash pulse. This analysis revealed a general trend of decreasing EDR ΔV parity with an increasing crash pulse duration, although overall differences remained low for most tests. Eleven tests, all with airbag deployments, converged towards an average of 3.3% error at the end of the crash pulse, which were 150-270 ms. EDR recorded ΔVs were in the range of 29.8-39.9 mph. Five tests, three of which were non-deployments, diverged to higher percentage error averaging 12.7% at an EDR ΔV of 31.8-40.0 mph. All higher error tests were 30% overlapped and had the highest crash pulse durations of 240-300 ms. One fully overlapped test generated highly unusual EDR data due to failure of the rear underride guard mounting bolts and plates.
Famiglietti, Nicholas, Hoang, Ryan, Fatzinger, Edward, Landerville, Jon
Innovative Active Head Restraint System in a Car: Safety Assessment with Virtual Human Body Model2020-01-09794/14/2020
The aim of this study is to use numerical simulations for safety assessment of an innovative active head restraint system. This system was developed to protect the head and neck of an occupant in a car without a head airbag during a side impact. Its FE model is created and embedded it in a model of a small car with a side airbag. The dynamics of the head restraint activation are also taken into account. The virtual human body model Virthuman is used to represent occupants. The model is scaled for pre-selected human individuals to cover large numbers of occupants of different sizes. It extends conventional virtual evaluation of new safety designs via existing pre-defined mono-purpose side dummies and their FE models. The benefit of the head restraint system is evaluated in side impact scenarios inspired by the pole tests performed by EuroNCAP. Transversal impacts to a pole at 29 and 32 km/h are considered at 90° and 75° angles from driver and the opposite side. Also, the far side impact prescribed with an acceleration pulse according to EuroNCAP is considered. Various initial driver sizes in standard seated positions are tested. To extend the study beyond standard testing protocols, out-of-position of driver is also considered, leading to more than 100 simulations of impact scenarios in total. The effect of the innovative head restraint system is assessed from the point of view of driver injury risk.
Vychytil, Jan, Hlucha, Jana, Kovar, Ludek, Kostikova, Martina, Moravcova, Pavlina, Bucsuhazy, Katerina
The Effects of Small Seat Swiveling Angles on Occupant Responses during a Frontal Impact2020-01-05714/14/2020
In highly automated vehicles (HAVs), new seat configurations may be desirable to allow occupants to perform new activities. One of the current HAV concepts is the swiveled seat layout, which might facilitate communication between occupants. The main objective of this study was to investigate the effects of seat swiveling angles on occupant kinematics and injury risk predicted by a Human Body Model (HBM) during a frontal impact. A detailed 50th percentile male 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 four 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 lateral supports on the seat pan. The effects of the seat swiveling angle were similar for all occupant positions. With the airbag in the nominal location, higher seat swiveling angles led to a higher head lateral displacement and a higher risk of head injury, especially for the BrIC criterion. The Sedan driver position had higher BrIC and a larger head lateral excursion than the other two positions. This could be mitigated by aligning the airbag location with the head. Pelvic fractures were also predicted for the configurations with the highest swiveling angles. These fractures were limited by the use of seat pan lateral supports. Overall, the model responses were sensitive to both seating configurations and occupant postures, and the results suggest that swiveled seating may increase the injury risk, especially for the head and pelvis. However, simple countermeasures, such as adapted airbag location or adding lateral seat pan supports, seemed possible to mitigate the risk.
Grébonval, Cyrille, Trosseille, Xavier, Petit, Philippe, Wang, Xuguang, Beillas, Philippe
The Effects of Front-Mounted Accessories on Air Bag Sensors and CrashworthinessJ2431_201910 (Current)10/9/2019
Almost all light trucks now are being manufactured with at least a driver side air bag and all will have dual air bags by 1998. The driving forces behind this feature are occupant safety, federal regulations, and competition in the industry. Along with the booming popularity of pickups and SUVs, they are commonly accessorized with a wide variety of products. Many accessories for four-wheel drives in particular are mounted on the front of the vehicle. These products include grille/brush guards, winches, snow plows, replacement bumpers, bicycle carriers, etc. Concerns have arisen over the compatibility of these accessories with the vehicle’s air bag system. The vehicle manufacturers are concerned because of their huge investment in design and crash test verification of the complete vehicle system and keen awareness of the federal regulations. The crushability of the front bumper and supporting structure are key elements in the system, so alterations to that area become logical concerns. The accessory manufacturers, dealers, and installers are concerned because the very core of their business could be at risk. The unknowns can range from fear of setting off an airbag while working on the vehicle to liability issues in an injury accident situation. In some cases, the installation of the product is contrary to recommendations from the vehicle manufacturer and may void the warranty. The ultimate customers (end users) are in a unique situation and are not being well served in some situations. Their dilemma stems from the conflict between what a manufacturer is willing to certify for sale and what the customer needs and expectations are. Their needs in vehicle equipment can vary widely from making a living to recreational lifestyle issues to simplify the desire to individualize. The precedent for front-mounted accessories is well established. The customers for both the vehicle and the equipment are there, so finding ways for them to coexist safely is beneficial to all.
Motor Vehicle Council
Latest mass-reducing innovations honored by Altair19AUTP09_099/1/2019
The fourth-generation Jeep Wrangler, which eliminated 92 kg (203 lb) compared to the previous-generation vehicle, and Ferrari's Portofino, which is 80 kg (176 lb) lighter yet 35% stiffer than the outgoing California T it replaces, were the Full Vehicle category winners of the 7th annual Altair Enlighten Awards, the widely-anticipated lightweighting competition sponsored by Altair and presented at the Center for Automotive Research (CAR) 2019 Management Briefing Seminars (MBS) conference in Traverse City, Mich. In the competition's Module category, mega-supplier ZF won for its latest low-mounted knee airbag design that replaces the typical metal housing with an industry-first fabric housing. Material Sciences Corp. (MSC) won top honors in the Enabling Technology category for MSC Smart Steel, the first ever spotweldable, low-density composite laminate to be used in a body application.
Gehm, Ryan
Machining Capabilities Enhance Space-Related ProgramsTBMG-347367/1/2019
Insaco Quakertown, PA
A Framework for Vision-Based Lane Line Detection in Adverse Weather Conditions Using Vehicle-to-Infrastructure (V2I) Communication2019-01-06844/2/2019
Lane line detection is a very critical element for Advanced Driver Assistance Systems (ADAS). Although, there has been significant amount of research dedicated to the detection and localization of lane lines in the past decade, there is still a gap in the robustness of the implemented systems. A major challenge to the existing lane line detection algorithms stems from coping with bad weather conditions (e.g. rain, snow, fog, haze, etc.). Snow offers an especially challenging environment, where lane marks and road boundaries are completely covered by snow. In these scenarios, on-board sensors such as cameras, LiDAR, and radars are of very limited benefit. In this research, the focus is on solving the problem of improving robustness of lane line detection in adverse weather conditions, especially snow. A framework is proposed that relies on using Vehicle-to-Infrastructure (V2I) communication to access reference images stored in the cloud. These reference images were captured at approximately the same geographical location when visibility was clear and weather conditions were good. The reference images are used to detect and localize lane lines. The proposed framework then uses image registration techniques to align both the sensed image (adverse weather) and the reference image. Once the two images are aligned, the lane line information from the reference image is then superimposed on the local map built by the ADAS or Autonomous driving system. A real-world experiment is designed to evaluate the error in localizing the lane lines using the proposed framework in comparison to ground truth data. The measurements and evaluations are based on data gathered from a test vehicle. The vehicle is equipped with a monocular camera, forward looking radar, LiDAR, and GPS/IMU. The initial results show good potential for improving upon current state-of-the art approaches used in today’s automotive industry.
Horani, Modar, Rawashdeh, Osamah
Residual Injury Situation and Accident Characteristics of Severe Motorcycle Accidents2019-01-06384/2/2019
The total number of persons severely and fatally injured in road traffic accidents has reduced considerably in recent decades. However, the number of motorcyclists involved in accidents has not reduced to the same extent, and some countries have even recorded an increase. The aim of this study is to analyse the circumstances of motorcycle accidents in Germany involving vehicles with a cubic capacity of over 125 cm3 with particular reference to severely or fatally injured riders. An analysis is to be made of the characteristics and patterns of injuries suffered by the most severely injured motorcyclists and proposals developed for injury prevention. The study included accident data from 464 motorcycle accidents collected in Hanover and Dresden between 2010 and 2015 by an academic research team in the course of the GIDAS project (German In-Depth Accident Study). This data represents a statistically representative sample from real accidents occurring in Germany. The analysis of the current injury situation shows that motorcyclists are often severely injured, i.e. suffered injuries of grade MAIS 3+ (so called serious injuries) in 16.9% of cases and thus around 9 times more frequently than car occupants. Motorcyclists wearing helmets suffered head injuries in approx. 20 % of cases. The serious injuries sustained were in particular skull fractures, including base of the skull and traumatic brain injuries are rare. Severe thoracic injuries included in particular rib and shoulder/clavicle fractures, often accompanied by injuries to internal organs. In terms of spinal injuries, the most common serious injuries were fractures of the thoracic spine, followed by fractures of the lumbar spine and cervical spine. In the abdominal area there were often severe injuries in the form of fractures in the pelvic area and accompanying injuries to internal organs. Arm injuries included, besides minor injuries (grazes, bruises, etc.), most commonly fractures of the hands/fingers and forearms, followed by elbow and upper arm fractures. Leg injuries seen in particular were femoral fractures as well as injuries to the muscles and tendons around the knee, also fractures of the shin and calf bones. Around the feet there were many fractures and dislocations of the wrist and ankle joints, as well as toes. The causes of the injuries, which were recorded in detail in the study for the various regions of the body and individual injuries, were most often caused by impact with the road and collision with objects and solid vehicle structural elements of cars and trucks. Serious injuries are linked with high energy respectively high relative impact speed.
Otte, Dietmar
Innovative Knee Airbag (KAB) Concept for Small Overlap and Oblique Frontal Impacts2019-01-06214/2/2019
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 appendage KAB concept design acts as a conventional KAB in full frontal impact modes (similar right inboard femur responses) and has the potential to reduce right inboard lower leg/foot responses by an average 16% (small overlap impact mode) and 20% (oblique impact mode) over the conventional KAB design. Furthermore, it was noted that the novel design could potentially be adapted to achieve targeted right inboard lower leg responses in full, offset and oblique frontal crash tests with minimal impact on the left outboard responses.
Makwana, Rahul, Jindal, Pardeep
Performance of Event Data Recorders Found in Toyota Airbag Control Modules in High Severity Frontal Oblique Offset Crash Tests2019-01-06334/2/2019
This paper presents an in-depth analysis of the performance of Event Data Recorders (EDRs) found in the Airbag Control Modules (ACMs), as tested in support of the National Highway Traffic Safety Administration’s Frontal Oblique Offset Program. Previous studies have examined EDR performance in high severity full-frontal barrier crash tests and moving deformable barrier side impact tests. This paper presents data from a high severity oblique frontal impact test in which the vehicle was struck by a moving deformable barrier. This paper examines the results of EDR data downloaded from two 2015 model year Toyota Highlanders, and the results of EDR reported change in velocity (delta-v), to vehicle mounted accelerometers and reference instrumentation. This paper will analyze EDR performance in reporting: Seatbelt buckle status, Occupant Size Classification, Front Passenger, Airbag and seatbelt pretensioner deployment time(s), Longitudinal delta-v, and Lateral acceleration/crash pulse.
Bortles, William, Hostetler, Ryan
Probability of Frontal Airbag Deployment in Bumper-Bumper and Underride Collisions2019-01-06204/2/2019
Airbag deployment thresholds can be a useful metric of collision severity in accident reconstruction applications. The National Automotive Sampling System (NASS) has provided a publicly-available database of real-world motor vehicle collisions, including more than 10,000 event data recorder (EDR) reports retrieved from airbag control modules. These reports typically indicate the airbag deployment status and the corresponding Delta-V of each recorded event. A prior study analyzing crash data in the NASS database demonstrated the airbag deployment threshold varies between vehicle manufacturers and over time. However, the analysis was limited to Ford and GM vehicles due to insufficient data. This paper expands on the prior study of frontal airbag deployment thresholds by analyzing newer years of NASS EDR data (4,000 additional reports). We found that the Delta-V threshold for a 50% probability of deployment event is higher for Toyota than for GM and Ford vehicles. Moreover, SUVs and pickup trucks had higher deployment thresholds than sedans. An increase in Delta-V thresholds was observed for more recent vehicle model years. A higher Delta-V is required for frontal airbag deployment in underride collisions, in which a sedan contacted a vehicle with higher ground clearance (SUV, pickup truck, or van), compared to collisions with direct bumper-bumper engagement. Based on the findings, we developed a logistic regression model that predicts the probability of frontal airbag deployment with a known change in velocity (ΔV = 0 to 45 mph), vehicle manufacturer (GM, Toyota, Ford), vehicle type (sedan, SUV, pickup truck), model year (1994-2001, 2002-2016), and impact configuration (underride, bumper-bumper) with 82% accuracy. This study provides information about airbag deployment behavior beyond what is reported in owner’s manuals and National Highway Traffic Safety Administration (NHTSA) guidelines.
Lee, Felix, McCleery, Caitlin H., Ngo, Christina, Limousis-Gayda, Manon, Hashish, Rami
The Swedish Word for AV Tech19AVEP03_083/1/2019
Veoneer, a new Tier 1 supplier with well-established roots, is moving rapidly into AI, says veteran research boss Ola Boström. The first automotive camera with built-in Deep Learning-considered to be a significant step forward in autonomous-vehicle sensor technology-is due to launch this year. It was developed and will be manufactured by a Tier 1 whose name is still seeking broader recognition in the industry. “What is a…Veoneer?” asked an engineer waiting in the taxi line at this year's CES, when a monorail train wrapped with the company's logo flashed past above. Building brand cred among countless other spin-offs and tech start-ups who are clawing for visibility takes time, of course, even for the independent, publicly-traded Swedish company with 8,600 employees, formerly known as Autoliv's Electronics segment.
Brooke, Lindsay
Challenges in the Regulatory Framework of Automated Driving2019-26-00971/9/2019
Automated Driving (AD) is foreseen to be one of the major social and technological challenges in the coming years. Many manufacturers are developing new models with cutting-edge functionalities, which are not included in the scope of the current regulatory framework. Apart from demonstrating their know-how and expertise about AD, their willingness to sell their AD models in the European market is accelerating the rule-making system. However, which is the roadmap for the European regulatory framework? Policy makers and regulatory bodies are pushing their boundaries at all levels (national and international) in order to introduce modifications in existing regulations. These regulations will enable the introduction of these new functionalities into the market. Without decreasing the standards of safety and security, the implementation of a clear and harmonized regulatory framework and approval process is extremely needed. The last amendments of the UN Regulation n°79 related to steering equipment or the creation of new standards such as the ISO 21448 regarding Safety and Intended Functionality (SOTIF) are examples of recent efforts from the regulatory bodies to achieve this goal. The aim of this paper is to show the regulatory framework state of the art regarding automated driving. In order to provide a thorough understanding of the forthcoming amendments and new standards, the different challenges that the European Commission (EC) / United Nations Economic Commission for Europe (UNECE) are facing will be analysed, as well as the different approaches to be considered by the international regulatory bodies. Finally, as a result of this research, the conclusions will be exposed as considerations and proposals for all players involved in this change of paradigm: users, manufacturers, authorities of approval and technical services.
Lafuente, Ignacio, Tobar, Marta, Luján, Carles, Martínez Rami, Estrella
Products of Tomorrow: January 2019TBMG-335941/1/2019
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
Device Detects Subatomic-Scale MotionTBMG-3339712/1/2018
It is relatively easy to measure small movements of large objects, but is much more difficult when the moving parts are on the scale of nanometers, or billionths of a meter. The ability to accurately measure tiny displacements of microscopic bodies has applications in sensing trace amounts of hazardous biological or chemical agents, perfecting the movement of miniature robots, accurately deploying airbags, and detecting extremely weak sound waves traveling through thin films.
Electrify the U.S. Postal fleet!18AUTP11_0111/1/2018
They're hot in the summer and cold in the winter, their drivers complain. Their sub-10-mpg fuel efficiency and emissions profile are stuck in the 1980s. Onboard fires are not uncommon due to poorly routed fluid lines. With rear-drive only, their traction in slippery road conditions is “scary,” according to U.S. Postal Service carriers who brave rain, snow and gloom of night in the Long Life Vehicle-the familiar residential mail truck that is finally nearing replacement. It's hard to believe that some 140,000 of these rolling boxes, based on 2wd Chevy S-10 chassis and gasoline engines, were assembled by Grumman, maker of sleek F-14 Tomcat jet fighters. But the cheap-and-crude LLV was the USPS's baby. Launched in 1986 for a 24-year lifecycle, it was given a six-year service extension in 2009. Then six years later the USPS kicked off its Next Generation Delivery Vehicles (NGDV) program to finally develop a mail truck for the 21st century.
Brooke, Lindsay
Autonomous vehicles present passive-safety challenges18AUTP10_0810/1/2018
Reclined and rotated seating positions are commonly depicted for autonomously driven vehicles. But for the Autoliv engineers tasked with developing occupant safety for tomorrow's self-driving vehicles, those previously improbable seating positions dictate innovative new passive safety protections. “Passive safety for autonomous vehicles is a pretty complicated problem to solve, which is why we're starting out with the simplest scenario: a frontal crash with a front occupant in a partial-recline position,” E. Scott Dershem, Autoliv's Vice President of Product Development, said in an interview with Automotive Engineering at the safety supplier's Auburn Hills, Michigan technical center.
Buchholz, Kami
Automotive Crashworthiness Design Optimization Based on Efficient Global Optimization Method2018-01-10294/3/2018
Finite element (FE) models are commonly used for automotive crashworthiness design. However, even with increasing speed of computers, the FE-based simulation is still too time-consuming when simulating the complex dynamic process such as vehicle crashworthiness. To improve the computational efficiency, the response surface model, as the surrogate of FE model, has been widely used for crashworthiness optimization design. Before introducing the surrogate model into the design optimization, the surrogate should satisfy the accuracy requirements. However, the bias of surrogate model is introduced inevitably. Meanwhile, it is also very difficult to decide how many samples are needed when building the high fidelity surrogate model for the system with strong nonlinearity. In order to solve the aforementioned problems, the application of a kind of surrogate optimization method called Efficient Global Optimization (EGO) is proposed to conduct the crashworthiness design optimization. Based on few samples, the initial Kriging models are constructed. Then the new sample found by the expected improvement criterion (EI) is employed to update the Kriging models in each subsequent loop iteration. Since the expected improvement criterion can balance the global search and local search, a global optimal design will be found after several iterations. Thus, EGO will reduce the number of computationally expensive evaluations while achieving the desired optimal design. The application of the EGO on vehicle crashworthiness design is demonstrated through a case of vehicle low speed crash design. And a comparison study between the EGO and traditional surrogate model based crashworthiness design optimization method indicates that the EGO method is more effective in crashworthiness design.
Fang, Yudong, Chen, Tao, Zhan, Zhenfei, Liu, Xu, Yu, Huili, Zhao, Hui
An SVM-Based Method Combining AEB and Airbag Systems to Reduce Injury of Unbelted Occupants2018-01-11714/3/2018
An autonomous emergency braking (AEB) system can detect emergency conditions using sensors (e.g., radar and camera) to automatically activate the braking actuator without driver input. However, during the hard braking phase, crash conditions for the restraint system can easily change (e.g., vehicle velocity and occupant position), causing an out-of-position (OOP) phenomenon, especially for unbelted occupants entering the airbag deployment range, which may lead to more severe injuries than in a normal position. A critical step in reducing the injury of unbelted occupants would be to design an AEB system while considering the effect of deployed airbags on the occupants. Thus far, few studies have paid attention to the compatibility between AEB and airbag systems for unbelted occupants. This study aims to provide a method that combines AEB and airbag systems to explore the potential injury reduction capabilities for unbelted occupants. By dividing the distance between the driver’s head and the top of the steering wheel into five regions, the possible area of head position was obtained by computational investigation for several combinations of braking acceleration and time. Using braking acceleration and time as input features, as well as real-time head position in one of five regions as an output feature, a support vector machine (SVM) classification model was trained and validated by the obtained data set. The ride-down efficiencies of the different regions were compared, and optimization for maximum delta-V reduction was conducted based on the SVM model under the prerequisite of guaranteeing high ride-down efficiency and appropriate forward displacement for the occupant. By utilizing the above-mentioned method to design the integrated safety systems including AEB and airbag systems, the safety benefits of this approach were demonstrated by comparing with those of the original design.
Zhou, Huajian, Hu, Manjiang, Zhong, Zhihua
Brazil's Option to Join iGLAD - International Harmonized In-Depth Accident Data2017-36-018311/7/2017
A strong local initiative in Campinas - Brazil is studying how to be more effective in the improvement of road safety in order to align to other worldwide initiatives with similar goals. This paper describes the Brazilian initiative’s approach to the challenge of being aligned with iGLAD (Initiative for the Global Harmonization of Accident Data, starting as a project in 2011 and collecting data since 2007) on the delivery of its first set of accident cases from 2016. The Brazilian source of data started as a pilot project collecting local data with the aim of extending it within the next years to a larger region. In fact, a consistent method for the development of strategies and measures to prevent accidents and mitigate injury severity comes from accident database analysis. Although databases such as national statistics are available for many countries for assessing accident situations, examining trends, or carrying out similar analysis; the identification of accident and injury causation and the evaluation of countermeasures require a higher level of detail. Comparison with other regions or countries in terms of that analysis has been an aim for many researchers. For this reason, several in-depth accident data collection projects have emerged worldwide in recent years. Unfortunately, comparative analysis of in-depth data from different countries is difficult or even impossible due to different standards for data collection and coding. For that purpose, Brazil needs to join the methods used in iGLAD, i.e. to process and merge the different data samples describing and overviewing the current status in terms of case counts, marginal distributions as is done by the countries participating from Europe, Asia, Australia and North and South America (currently only Brazil) providing data for iGLAD. As an application example, the iGLAD dataset from 2007 to 2015 was used to analyze the distributions of accident types, presence of safety systems, characteristics of collision deformation and injury severity for each country and to provide country comparisons. The status of Brazil can be assessed in that frame and also capabilities for pre-crash analysis can be assessed. Exemplary statistical assessment of injury probability and descriptive statistics for comparison between different countries were given as a result of the analysis and for the Brazilian sample will give the first trends. This paper gives an overview of the Brazilian data in the framework of the iGLAD initiative as a new field crash data set and shows its unique opportunities for road accident analysis in a global scope, which are not provided by any other accident data source and will give stronger support for efficient and consistent traffic policies. The analysis according to the harmonized data helps to address challenges of road safety on a global level, whether through the identification of country-specific issues and measures to address them or the harmonization of legislation and ratings.
Longton, Alejandro, Schulze, Oliver, Bakker, Jörg, Parera, Nuria, Leitao, Joel
Potential Effects of Deceleration Pulse Variations on Injury Measures Computed in Aircraft Seat HIC Analysis Testing2017-01-20529/19/2017
Aircraft seating systems are evaluated utilizing a variety of impact conditions and selected injury measures. Injury measures like the Head Injury Criterion (HIC) are evaluated under standardized conditions using anthropomorphic dummies such as those outlined in 14 CFR part 25. An example test involves decelerating one or more rows of seats and allowing a lap-belted dummy to impact components in front of it, which typically include the seatback and its integrated features. Examples of head contact surfaces include video monitors, a wide range of seat back materials, and airbags. The HIC, and other injury measures such as Nij, can be calculated during such impacts. A minimum test pulse, with minimum allowable acceleration vs time boundaries, is defined as part of the regulations for a frontal impact. In this study the effects of variations in decelerations that meet the requirements are considered. A series of Finite Element simulations of a generalized aircraft seat were performed to determine the variation in HIC and Nij observed based on variations in the deceleration pulse. The results indicate that the pulse characteristics affect the resulting head motions and can influence the ability to pass the HIC analysis test.
Friedman, K, Mattos, G, Bui, K, Hutchinson, J, Jafri, A, Paver PhD, J
Euro NCAP to adopt autonomous vehicle ratings17AUTP04_114/1/2017
The Euro New Car Assessment Program (NCAP) safety-test rating will establish a separate category for autonomous vehicles, but there is not likely to be one for cars that are claimed to protect all occupants from serious injury or death. And while there is currently little sign of a harmonized engineering and cost saving global test system, there may be an opportunity in the future, reckons Matthew Avery, Director of Insurance Research at Thatcham Research, which carries out Euro NCAP tests in the U.K. According to Michiel van Ratingen, the Euro NCAP General Secretary, there has been a “slow down” in new safety systems' progress. According to Avery, this isn't due to lack of ideas.
Birch, Stuart
Avoiding Safety Scandals by Controlling the Risk of Material Changes2017-01-03733/28/2017
Achieving functional safety in mechatronic systems with growing product functionality is a major challenge in systems engineering. Following the current discussion, this challenge is mostly allocated to electronics and software development. For most of the scenarios this focus is feasible. Product design - the construction of the product - defines the properties and the appearance of the product by shape, material and assembly. So, the product design is often not under control of the safety management system. A hazardous deviation of part shape can be easily identified after the parts product or at least at its mounting. A wrong assembly is controlled by assembly documentation or data (e.g. screw torques) and identified at end of assembly line checks. The identification of a hazardous material choice depends on the product material class. Product materials can be separated into two classes: passive or active materials. Passive materials (e.g. car body) can be distinguished in as passive materials with constant shape (stiff) and variable shape (flexible) (e.g. damper, spring). The liability of those materials regarding their usage in the product is tested in labs in prototypes in prior. Active materials (e.g. fluids, gases), or functional materials fulfill, trigger or directly influence the functionality of the product. The choice of a functional material is not always made by the electronics engineering. Therefore, it is not under control of safety management processes. Never the less functional material, especially with radical behavior, underlie other safety regulation. Explosives for example, can be integrated in a product or system and are restricted by specific standards. This technology report reflects the verification methods of functional materials today. The responsibility of the product design engineer is discussed as well as the relevant standards. The challenge of achieving complete product compliance with functional materials is shown by the technology analysis of the Takata airbag recall. The required and available methods to control risks of functional materials choice and change are listed and rated. Gaps in existing engineering processes and regulations are identified. A strategy to close those gaps is explained.
Koark, Fabian Jorg Uwe, Beul, Christian
Mechatronics Based Accident Alarming System with Automatic Roadblock Prevention System2017-01-17283/28/2017
In any unlikely event of accidents or vehicle breakdown, there is accumulation of traffic which results in road-blockage and causes in convenience to other vehicles. If this happens in remote areas, the accidents victims are left unattended and there is delay in providing emergency services. In case of traffic, it obstructs the entry of ambulance and rescue team which results in death of passengers. To prevent this mishap, a mechatronics based road block avoidance and accident alarming system is designed which is automated by the use of sensors. The road-block is detected with the help sensors located at regular intervals on road. This input is given to a Local Control Unit (LCU) which is integrated on every road. Several such LCUs are connected to a Main Control Unit (MCU) which is located at the nearest police station. A single MCU covers the area administered by that police station. Additional CCTV cameras are present to give graphical view of accident. The MCU alerts the Traffic department, nearest Hospital and currently running ambulances for initiation of emergency services. There is also a group of small modular retractable robots which blocks the nearest entrance of the road to prevent further traffic accumulation. This paper shows the technology behind the this concept and its implementation
Singh, Nitin, Sharma, Aayoush, Shah, Sameer, Gardampaali, Balakumar
Automating Regional Rib Fracture Evaluation in the GHBMC Detailed Average Seated Male Occupant Model2017-01-14283/28/2017
Computational modeling of the human body is increasingly used to evaluate countermeasure performance during simulated vehicle crashes. Various injury criteria can be calculated from such models and these can either be correlative (HIC, BrIC, etc.) or based on local deformation and loading (strain-based rib fracture, organ damage, etc.). In this study, we present a method based on local deformation to extract failed rib region data. The GHMBC M50-O model was used in a Frontal-NCAP severity sled simulation. Failed Rib Regions (FRRs) in the M50-O model are handled through element deletion once the element surpasses 1.8% effective strain. The algorithm central to the methodology presented extracts FRR data and requires 4-element connectivity to register a failure. Furthermore, the FRRs are localized to anatomical sections (Lateral, Anterior, and Posterior), rib level (1,2,3 etc.) and element strain data is recorded. FRRs crossing multiple anatomical sections were treated in each section but can be back calculated using a total failure count. These were then used to generate visual summaries for each time point with FRRs per each rib level and section depicted numerically and visually through an overlaid heat map. A total failure count is also displayed at the bottom of each table for each side. While correlative solutions for rib injuries have been published, the methodology presented is for users who prefer to investigate rib failure through element elimination. The techniques employed here are similar to methods presented in literature to determine real-world rib fracture location and patterns. A sample case with a nominal delta-V of 56.4 kph was examined for algorithm evaluation.
Guleyupoglu, Berkan, Barnard, Ryan, Gayzik, F. Scott
A Sensitivity Study on Inertance Frequency Response Function through Non-Parametric Variability Approach2017-01-04453/28/2017
In recent years, there is increasing demand for every CAE engineer on their confidence level of the virtual simulation results due to the upfront robust design requirement during early stage of an automotive product development. Apart from vehicle feel factor NVH characteristics, there are certain vibration target requirements at system or component level which need to be addressed during design stage itself in order to achieve the desired functioning during vehicle operating conditions. Vehicle passive safety system is one which primarily consists of acceleration sensors, control module and air-bag deployment system. Control module’s decision is based on accelerometer sensor signals so that its mounting locations should meet the sufficient inertance or dynamic stiffness performance in order to avoid distortion in signals due to its structural resonances. During design stage, the inertance or dynamic stiffness can be assessed through the finite element (FE) based technique of modal frequency response function (FRF) analysis. FE model is deterministic and the modal frequency response function results are sensitive to the modeling techniques especially at the high frequencies due to the high modal densities. Hence the correlation of FRF results between test and simulation are highly challenging especially at the mid and high frequency band. In this paper a passive safety system control module mounting bracket is considered for the drive point FRF analysis and the correlation at system level is performed by simulating the physical bench test condition. The non-parametric variability method (NPVM) approach is used to study the system level vibration response variations due to the uncertainties in finite element modeling. Finally the updating of finite element model is made to improve the correlation level in terms of covering the test FRF response within FE results variability envelope is also highlighted in this scope of study.
Arunachalam, Muthukumar, S, Arunkumar, Sampath, PraveenKumar, Haiyum, Abdul, Khakhar, Yash
Bolt EV seat design cuts weight, delights taller passengers16AUTP08_088/1/2016
Stepping into the back seat of Chevrolet's 2017 Bolt EV, one attribute of the car is immediately evident: the designers and engineers didn't neglect the outsized physical dimensions of tall passengers. In fact, even those whose height and inseam length are well beyond the 90th percentile-that would include the author-will appreciate the Bolt EV's surprisingly easy ingress and egress. That's because the car's front seats were designed with the back-seaters in mind, as well as being designed to reduce mass.
Brooke, Lindsay
Enhancement of Vehicle Handling Based on Rear Suspension Geometry Using Taguchi Method2015-01-90204/15/2016
Studies have shown that the number of road accidents caused by rollover both in Europe and in Turkey is increasing [1]. Therefore, rollover related accidents became the new target of the studies in the field of vehicle dynamics research aiming for both active and passive safety systems. This paper presents a method for optimizing the rear suspension geometry using design of experiment and multibody simulation in order to reduce the risk of rollover. One of the major differences of this study from previous work is that it includes statistical Taguchi method in order to increase the safety margin. Other difference of this study from literature is that it includes all design tools such as model validation, optimization and full vehicle handling and ride comfort tests. Rollover angle of the vehicle was selected as the cost function in the optimization algorithm that also contains roll stiffness and height of the roll center. In order to form the cost function, five different geometrical factors have been selected as design variables. The ultimate aim is to minimize the cost function by increasing the roll center height and suspension roll stiffness. To run the optimization routine, a rigid rear suspension mechanism used on the 7 m bus has been modeled using Adams/Car software program. Opposite wheel travel analysis has been performed as an optimization test method in order to simulate the vehicle passing over the bump. Then, in order to reach the minimum value of the cost function, statistical Taguchi method was used to perform design of experiments (DOE). In total, 27 experiments have been performed according to the selected design variables. Therefore, in each different experiment, the roll center height and the roll stiffness were measured. Then, the cost function was calculated and recorded to compare with the future iterations. The attachment points giving minimum cost function value are expected to be the optimal coordinates for installing the suspension mechanism.
Sert, Emre, Boyraz, Pinar
A Cost-Effective Model-Based Approach for Developing ISO 26262 Compliant Automotive Safety Related Applications2016-01-01384/5/2016
Automotive manufacturers and their suppliers increasingly need to follow the objectives of ISO 26262 as it is now state-of-the art and as it is the case that an ever increasing number of active and passive safety systems are developed within cars. This has increased the need to define a safe system development process. This paper proposes a model-based approach including automatic and certified code generation to efficiently implement the embedded software that controls these systems while meeting the needed safety requirements and obeying the rules of ISO 26262.
Dion, Bernard
An Investigation of Body Inertance Response for Occupant Safety Control Module Attachment Regions2016-01-04734/5/2016
Current generation passenger vehicles are built with several electronic sensors and modules which are required for the functioning of passive safety systems. These sensors and modules are mounted on the vehicle body at locations chosen to meet safety functionality requirements. They are mounted on pillars or even directly on panels based on specific packaging requirements. The body panel or pillar poses local structural resonances and its dynamic behavior can directly affect the functioning of these sensors and modules. Hence a specific inertance performance level at the mounting locations is required for the proper functioning of those sensors and modules. Drive point modal frequency response function (FRF) analysis, at full vehicle model for the frequency range up to 1000 Hz, is performed using finite element method (FEM) and verified against the target level along with test correlation. The arrival of acceptable inertance levels across the wide range of frequency is a highly challenging job and here topography FRF optimization technique is leveraged for improving the design. Design improvements have to be made based on simulation results until the proto build phase of a vehicle program. This paper describes the investigation of inertance performance level and its improvement through simulation techniques during design phase, later on how the drive point hammer impact measurement results are utilized for correlating with FEM model for further fine tuning of the design changes before vehicle launch.
Arunachalam, Muthukumar, Arunkumar, S, Sampath, PraveenKumar, Haiyum, Abdul, Katz, Beverly
Integration Strategy of Safety Systems - Status and Outlook2016-01-14994/5/2016
On the way to automated driving, the installation rate of surround sensing systems will rapidly increase in the upcoming years. The respective technical progress in the areas of driver assistance and active safety leads to a numerous and valuable information and signals to be used prior to, during and even after an accident. Car makers and suppliers can make use of this new situation and develop integrated safety functions to further reduce the number of injured and even deaths in car accidents. Nevertheless, the base occupant safety remains the core of this integrated safety system in order to ensure at least a state-of-the-art protection even in vehicles including partial, high or full automation. Current networked safety systems comprehend a point-to-point connection between single components of active and safety systems. The optimal integration requires a much deeper and holistic approach. This paper and presentation describe current and future challenges and a clear strategy for the product management as well as for the development and validation of integrated safety systems. The starting points are: market and field requirements based on accident research data, components and technologies brought into the market through driver assistant and automated driving functions as well as design and validation methods to minimize development cost for the targeted performance. This paper will also include an overview of current and future integrated safety functions, the required functional and E/E architectures and the respective roadmap. Technical examples for pre-and in-crash functions will be described including a design overview, HW components and results.
Klier, Willy, Lich, Thomas, D’Addetta, Gian Antonio, Freienstein, Heiko, Koehler, Armin, Reckziegel, Bastian, Yu, Zerong
Development of Plastic Fracture Simulation Technology for Passenger Airbag Tear Line2015-01-13414/14/2015
The explicit methods analysis solver LS-DYNA was used to create technology for simulating airbag deployment and plastic airbag lid tear-away in the front passenger seat. The present study clarified the mechanical properties and the transitions in fracture pattern of the material at low temperature plastic this way, an appropriate modeling method was developed and the prediction accuracy of the simulation of airbag lid tear-away on deployment was increased. Tensile testing of the material was carried out where there were differences in thickness of the tear-away section and the fracture characteristics were determined. A material model was created by analyzing changes in fracture characteristics and collapse patterns, taking into consideration the effects of strain and strain rate localization on fracture strain as well as ductile-brittle fracture transition. Next, airbags were subjected to the impactor testing. It was confirmed that the reaction force characteristics with that impactor had a good correlation with the simulation model. Finally, the airbag that matched the reaction force characteristic and the instrument panel model were combined. The simulation result was compared with the experimental results of the tear-away deployment, leading to good correlations with the tear-away process in simulations and experiments. It was also found that the two factors were important with regard to the reproducibility of the progressive tear-away process. They were changes in fracture mode due to the strain rate and strain rate dependence of fracture strainIn addition, it is necessary to pay careful attention to the modeling method due to the varying material thickness. More over prototypes with various significant parameters were created and subjected to accuracy verification. These prototypes also yielded good results for reproducibility. The sufficient accuracy aimed to reduce the number of prototypes in the vehicle development was confirmed.
Sugaya, Hisaki, Tosa, Yoshiyuki, Imura, Kazuo, Mae, Hiroyuki
Simplification of the Variable Vent Structure of the Passenger Airbag by Applying a Slit-Type Vent2015-01-14554/14/2015
The reaction force of a traditional passenger airbag tends to reduce after the initial inflation and before contact with the occupant, since the vent structure discharging the internal gas is always open. A potential means to prevent this drop in the airbag reaction force includes the addition of a variable vent structure which keeps the vent hole closed until occupant contact to maintain the airbag internal pressure and then opens to vent gas after the contact. However, variable vent structures may involve issues from a complicated structure due to additional parts in its construction. The goal of this study was to develop a simplified variable vent structure. A slit-type vent structure was investigated. This structure incorporates no additional parts to a conventional airbag with a hole-type vent. Static deployment tests and impactor tests were conducted to measure the effect of the slit-type vent structure and to compare it with the conventional airbag. Additionally, the correlation between slit length/depth and the airbag reaction force was investigated by performing impactor tests to clarify the potential contribution of this vent structure to the optimization of the overall restraint system. The results of this study showed that a simple variable vent concept was achieved with the slit type vent structure. It was also found that the slit length and depth correlates with the airbag reaction force.
Torikai, Kenshi, Higuchi, Hitoshi, Seki, Kazuhiro
Effects of Crash Pulse, Impact Angle, Occupant Size, Front Seat Location, and Restraint System on Rear Seat Occupant Protection2015-01-14534/14/2015
In this study, two sled series were conducted with a sled buck representing a compact vehicle. The first series of tests focused on the effects of crash pulse, impact angle, occupant size, and front seat location on rear seat occupant restraint with a generic rear-seat belt system without pre-tensioner or load limiter. The second series of tests focused on investigating the benefit of using advanced features for rear-seat occupant restraint in the most severe crash condition in the first sled series. The first series of tests include 16 test conditions with two impact angles (0° and 15°), two sled pulse (soft and severe), and four ATD sizes (HIII 6YO, HIII 5th female, HIII 95th male, and THOR-NT) with two ATDs in each test. The driver seat was located at the mid position, while the front passenger seat was positioned such that a constant distance between the ATD knee and the front seat is achieved. In all the tests, a generic rear-seat belt system without pre-tensioner, load limiter or dynamic locking tongue (DLT) was used. Test results from the first sled series showed that crash pulse and occupant size are the two dominating factors affecting the ATD kinematics and injury measurements, while impact angle and front-seat location are not statistically significant. Although no head-to-front-seat contact occurred in any of the tests, in general, the severe crash pulse would result in chest deflections over the injury criteria for adult ATDs with higher ATD excursions than for the soft crash pulse. These results are consistent to those from the field data in that chest injuries are the most common injuries in rear-seat adult occupants. The HIII 6YO ATD sustained submarining kinematics in all the tests due to the slouching pre-crash posture. In an attempt to help further reduce the chest loading while managing the head excursion, 3-point belts with pre-tensioner and load limiter, 4-point belts, DLT, inflatable belts, Bag in Roof (BiR) concept, and Self Conforming Rear-seat Air Bag (SCaRAB) concept were investigated in the second series of sled tests, in which only the most severe testing condition (0° and severe pulse) in the first sled series was used. Reductions in occupant loading were shown with these advanced restraint systems, especially the airbag features, to help reduce head, neck, and chest injury measures for rear-seat occupants. This study demonstrated the importance of considering the effects of occupant size and crash pulse on rear-seat occupant protection. Advanced restraint systems including features such as a pre-tensioner, a load limiter, and an airbag, may have the potential to help provide additional protection for rear-seat occupants with diverse occupant sizes.
Hu, Jingwen, Fischer, Kurt, Lange, Paul, Adler, Angelo
Low Light Image Enhancement Using Color Transfer2015-01-03124/14/2015
Advanced Driver Assistance System (ADAS) in combination with other active safety features like air bags etc. is gaining popularity. Vision based ADAS systems perform well under ideal lighting, illumination and environmental conditions. However, with change in illumination and other lighting related factors, the effectiveness of vision based ADAS systems tend to deteriorate. Under conditions of low light, it is therefore important to develop techniques that would offset the effects of low illumination and generate an image that appears as if it were taken under ideal lighting conditions. To accomplish this, we have developed a method, that uses local color statistics from the host image with low illumination, and enhance the same using an adaptive color transfer mechanism. By taking cues from the properties of ideal images that are saved in a database, the proposed method tends to recreate the input scene (with low illumination), into a near ideal scene, based on the database images. Visual and quantitative evaluation of our method confirms that it performs well under very low light conditions as well, where standard algorithms tend to fail.
Gangadharan, Jiji, Mani, Shanmugaraj, Kutty, Krishnan
From Natural Language to Semi-Formal Notation Requirements for Automotive Safety2015-01-02654/14/2015
The standard ISO 26262 stipulates a “top-down” approach based on the process “V” model, by conducting a hazard analysis and risk assessment to determine the safety goals, and subsequently derives the safety requirements down to the appropriate element level. The specification of safety goals is targeted towards identified hazardous events, whereas the classification of safety requirements does not always turn out non-ambiguous. While requirement formalization turns out to be advantageous, the translation from natural language to semi-formal requirements, especially in context of ISO 26262, poses a problem. In this publication, a new approach for the formalization of safety requirements is introduced, targeting the demands of safety standard ISO 26262. Its part 8, clause 6 (“Specification and management of safety requirements”) has no dedicated work product to accomplish this challenging task. The five levels of requirements for writing safety requirements are distributed throughout the standard, increasing the probability of misapplication. For these reasons, a dedicated requirement template is proposed. It is applicable for writing new or checking existing requirements, independent of any tool. By reviewing a number of industrial relevant use cases the applicability of the new template is verified and its effectiveness is demonstrated. Furthermore, a semi-formal notation technique is shown to express these formalized requirements, including their associated attributes and resulting relationships. By following the proposed approach, we meet the obligations of ISO 26262 to write e.g. unambiguous, consistent, verifiable, and complete requirements. In the end, this has the potential to dramatically reduce the probability of systematic failures during development of automotive embedded systems.
Krammer, Martin, Stirgwolt, Philip, Martin, Helmut
Development of Prediction Method for Dynamic Strain on Windshield during Passenger Airbag Deployment2015-01-13304/14/2015
The objective of this study is to accurately predict the dynamic strain on the windshield caused by the deployment of the airbag in a short term without vehicle tests. The following assumption is made as to the dynamic pressure distribution on the windshield: The deployment of the airbag is fast enough to ignore spatial difference in the patterns of the pressure time histories. Given this assumption, significant parameters of the dynamic pressure distribution are as follows: 1) the distribution of the maximum pressure during contact between the airbag and the windshield, and 2) the characteristic of the force time histories applied to the windshield by the deploying airbag. In this study, the prediction method consists of a simplified airbag deployment test and an FE simulation. The simple deployment test was conducted to measure the peak pressure distribution between the airbag and a flat panel simulating the windshield. The pressure time history curves were determined by scaling the force time histories from the load cells. The scale factor was identified for each of the measuring points on the pressure measurement film. Prescribed pressure time histories were directly applied to the part of the FE mesh specifically used to load the windshield. In order to validate the developed prediction method, the strain from the FE simulation was compared with that from strain gauges in the vehicle tests. The results showed that the predicted strain on the windshield caused by the airbag deployment correlated well with the data measured in the vehicle tests, suggesting that the prediction method developed in this study can be a valuable tool for improving the efficiency of development.
Tosa, Yoshiyuki, Mae, Hiroyuki
Finite-Element-Based Transfer Equations: Post-Mortem Human Subjects versus Hybrid III Test Dummy in Frontal Sled Impact2015-01-14894/14/2015
Transfer or response equations are important as they provide relationships between the responses of different surrogates under matched, or nearly identical loading conditions. In the present study, transfer equations for different body regions were developed via mathematical modeling. Specifically, validated finite element models of the age-dependent Ford human body models (FHBM) and the mid-sized male Hybrid III (HIII50) were used to generate a set of matched cases (i.e., 192 frontal sled impact cases involving different restraints, impact speeds, severities, and FHBM age). For each impact, two restraint systems were evaluated: a standard three-point belt with and without a single-stage inflator airbag. Regression analyses were subsequently performed on the resulting FHBM- and HIII50-based responses. This approach was used to develop transfer equations for seven body regions: the head, neck, chest, pelvis, femur, tibia, and foot. All of the resulting regression equations, correlation coefficients, and response ratios (FHBM relative to HIII50) were consistent with a set of test-based results. The HIC15 transfer equation was used to transform the cadaver-based risk curve into the HIII50 domain.
El-jawahri, Raed E., Laituri, Tony R., Kim, Agnes S., Rouhana, Stephen W., Weerappuli, Para V.
Evaluation of Air Bag Electronic Sensing System Collision Performance through Laboratory Simulation2015-01-14844/14/2015
Since their inception, the design of airbag sensing systems has continued to evolve. The evolution of air bag sensing system design has been rapid. Electromechanical sensors used in earlier front air bag applications have been replaced by multi-point electronic sensors used to discriminate collision mechanics for potential air bag deployment in front, side and rollover accidents. In addition to multipoint electronic sensors, advanced air bag systems incorporate a variety of state sensors such as seat belt use status, seat track location, and occupant size classification that are taken into consideration by air bag system algorithms and occupant protection deployment strategies. Electronic sensing systems have allowed for the advent of event data recorders (EDRs), which over the past decade, have provided increasingly more information related to air bag deployment events in the field. To further aid in the evaluation of air bag field performance and interpretation of EDR downloads, a test methodology was developed so that controlled actuation of air bag system sensing elements could be achieved that accurately simulates vehicle collision dynamics. This was accomplished with the air bag control module removed from the vehicle and installed on physical actuators (linear and/or rotary) while still connected to the vehicle wiring harness. Controlled excitation of air bag sensing elements while simultaneously monitoring the outputs of the air bag system control module allows for assessment of system performance under various collision pulses and state sensor conditions. The presented test methodology provides a tool for evaluating field performance and EDR reporting in a controlled laboratory environment, without a priori knowledge of the underlying air bag algorithm or the expense and difficulty of running vehicle crashes.
Toomey, Daniel E., Winkel, Eric S., Krishnaswami, Ram
Interior Trims Design Considerations for Roof Mounted Curtain Airbag2015-26-01571/14/2015
Curtain airbag design offers protection in side crash and it plays a critical role in safety of the vehicle. Curtain airbag provides protection to the occupant in many impact events like frontal offset, side barrier, and side pole and rollover condition. For a vehicle to be safe for any side impact condition, the curtain airbag should deploy and take its final shape before any injury happens to the occupant. During deployment, it is important that the airbag chooses a path of minimum resistance and does not get entangled in interior trims. In reality, the trims always do obstruct the path of airbag deployment in some way. Hence, special care has to be taken care for designing areas surrounding curtain like providing hinges, deflector components etc. to avoid being caught. There are about ten different factors on this deployment is dependent upon. This paper discusses these factors and the effect of the factors on the trims and airbag development. Proper care needs to be taken while designing the airbag mounting locations and the protrusions from the trims.
Hendre, Kedar Madhukar, Purohit, Yogesh
The Effect of Pre-Crash Safety Systems to Occupant Protection in Offset Frontal Impacts2015-26-01641/14/2015
The ASSESS project is a European Commission co-funded project that aimed to develop harmonized and standardized assessment procedures for collision mitigation and avoidance systems. ASSESS was one of the first European projects which dealt in depth with the concept of integrated safety, defining methodologies to analyse vehicle safety from a global point of view. As such, the developed procedures included driver behaviour evaluation, pre-crash and crash system performance evaluation and socio-economic assessment. The activities performed for the crash evaluation focussed on the influence of braking manoeuvres in occupant positioning through dynamic braking manoeuvres with real occupants and Madymo and LS-Dyna simulations. The assessment of the passive safety protection level according to the results of the influence of the active systems is based on sled testing and full vehicle testing. This paper focusses on braking manoeuvres with volunteers and full vehicle tests for frontal offset deformable barrier impact configuration. The results show the effects of the pre-crash systems activation on the crash course, i.e. changes to the impact speed in combination with changes of occupant positioning, both due to pre-braking. The effects are quantified using the dummy injury criteria obtained from offset deformable barrier crash tests. The effects of different pre-crash system elements were analysed separately by comparing the results for the tested scenarios. As of today, there is no regulation, assessment program, or other similar official procedure in place for systematically assessing pre-crash systems during the crash phase. The presented work is a first step for an integrated evaluation comprising pre-crash and crash phases.
Infantes, Eduard, Caspar, Marie-Estelle, Kramer, Simon, Schaub, Swen, Langner, Tobias, Eggers, André, Unselt, Thomas, Lemmen, Paul
Airbag Deployment Thresholds from Analysis of the NASS EDR Database2014-01-04964/1/2014
Accident reconstructionists and others use airbag non-deployment thresholds as an indicator of severity in minor- to moderate-severity accidents. The National Automotive Sampling System (NASS) has accessed and recorded the data stored in the airbag control modules of nearly 6,300 vehicles since 2000 and has made these data publicly available. The goal of this study is to ascertain thresholds from the data based on delta-V and seatbelt use, studying how they may differ among manufacturers and over time. Other data is also examined, such as seatbelt pre-tensioner fire times and airbag deployment signal times. These data have been analyzed for use in accident reconstruction for vehicles which may or may not be supported by a publicly available module download tool. While manufacturers at one point published deployment data in owner's manuals, this has not been the case for approximately five to ten years. The dataset analysis will compare the published data for deployment thresholds to real world accidents. Over time, with the addition of occupant classification systems and dual-stage airbags, there has been an increase in variability for airbag deployment times and thresholds. The analysis thus far shows the thresholds from the dataset to be in general agreement with published data.
Wood, Matthew, Earnhart, Nicholas, Kennett, Kelly
Automatic Maneuver Boundary Detection System for Naturalistic Driving Massive Corpora2014-01-02724/1/2014
Towards developing of advanced driver specific active/passive safety systems it is important to be able to continuously evaluate driving performance variations. These variations are best captured when evaluated against similar driving patterns or maneuvers. Hence, accurate maneuver recognition in the preliminary stage is vital for the evaluation of driving performance. Rather than using simulated or fixed test track data, it is important to collect and analyze on-road real-traffic naturalistic driving data to account for all possible driving variations in different maneuvers. Towards this, massive free style naturalistic driving data corpora are being collected. Human transcription of these massive corpora is not only a tedious task, but also subjective and hence prone to errors/inconsistencies which can be due to multiple transcribers as well as lack of enough training/instructions. These human transcription errors can potentially hinder the development of algorithms for advanced safety systems, and lead to performance degradations. In order to prevent these errors from propagating, an automatic maneuver boundary (also activity) detection system (or in short a MAD tool) utilizing filterbank analysis of vehicle dynamic signals is proposed. Using a minimal set of generic vehicle dynamic sensor information, it is shown that the MAD tool can match human transcription to an accuracy of up to 99%. The tool performs equally well on CAN-bus signals as well as inertial sensor information from a portable device. This simple, accurate, and computationally efficient tool can help mitigate human transcription errors and make valuable data from large naturalistic driving corpora more accessible.
Sathyanarayana, Amardeep, Sadjadi, Seyed Omid, Hansen, John H. L.
A Proposal of Middle Speed Hybrid III 50 th Dummy Chest Calibration Test2014-01-08104/1/2014
The Hybrid III 50th male dummy is widely used in front impact crash tests in the world to evaluate the vehicle safety performance. The chest impact calibration test should be conducted after certain amount of crash tests to ensure that the dummy has the right performance during the crash tests. The impact velocity in the current chest calibration tests is 6.71 m/s and the chest displacement corridor is 63.5 mm to 72.6 mm, which was based on the cadaver tests carried out in 1970s. After over forty years' development, the vehicle safety has been improved significantly with applications of seat belt and airbag technologies. In the European and China new car assessment program (ENCAP and CNCAP), the higher performance limit for the front impact dummy chest compression is 22mm and the lower performance limit is 50 mm, which is much lower than the dummy chest calibration corridor. In this paper, the dummy rib assembly structure is analyzed and the rib impact FEA simulation was also conducted. It is found the high speed impact will cause the damping material fracture, which is glued on the rib steel, and the glue de bonding. A proposal of middle speed chest calibration test with compression of about 50 mm was made to match the ENCAP and CNCAP lower performance limit.
Zhao, Youmei
Curtain Airbag Linear Impact Simulation Method for FMVSS 226 and NCAP Side Impact2014-01-08054/1/2014
In current inflatable curtain airbag development process, the curtain airbag performance is developed sequentially for the airbag coverage, FMVSS 226, FMVSS 214 and NCAP. Because the FMVSS 226 for the ejection mitigation and the NCAP side impact test require the opposite characteristics in terms of the dynamic stiffness of the inflatable curtain airbag, the sequential development process cannot avoid the iteration for dynamic stiffness optimization. Airbag internal pressure characteristics are can be used to evaluate the airbag performance in early stage of the development process, but they cannot predict dynamic energy absorption capability. In order to meet the opposite requirements for both FMVSS 226 and NCAP side impact test, a test and CAE simulation method for the inflatable curtain airbag was developed. The purpose of this study is to standardize the test setup for comparing the energy absorption capability of inflatable curtain airbag and to make criteria for meeting both FMVSS 226 and NCAP early in the program. This test and CAE simulation method can be used for A to B comparison between curtain airbags and for quantifying the dynamic restraint capability of inflatable curtain airbag. The robust design considering the real crash environment was conducted to determine the best test parameters, for example the shape of the impactor, impact velocity and impactor mass. The developed criteria of the linear impact simulation can be used to meet both FMVSS 226 and NCAP in early stage of the program.
Lee, Jeong Keun, Ahn, Byung-Jae, Hong, Ye Ri
Under-Body Blast Mitigation: Stand-Alone Seat Safety Activation System2014-01-05564/1/2014
This work is based on a current project funded by the United States Army Small Business Innovation Research (SBIR) Program and is being conducted with the Tank Automotive Research, Development and Engineering Center (TARDEC) Ground Systems Survivability (GSS) Team and Paradigm Research and Engineering. The focus of this project is to develop an advanced and novel sensing and activation strategy for Pyrotechnic Restraint Systems, Air Bags and other systems that may require activation. The overriding technical challenge is to activate these systems to effectively protect the Soldier during blast events in addition to Crash, Rollover and Other Injury Causing events. These activations of Pyrotechnic systems must occur in fractions of milliseconds as compared to typical automotive crashes. By investigating systems outside of typical accelerometer based applications and activations, the potential exists to exploit systems that require little power, are self-contained and provide the required output for the desired result. As such Constant-Flux Magnetostrictive Sensors shall be evaluated in a self-contained environment to provide the output during these events. By activating the Pyrotechnic Restraint Systems and Air Bag Systems early in Blast Events, the systems can Restrain the Occupant and provide flail protection from surfaces within the vehicle. As the system is developed various test scenarios will be introduced to activate these systems and design a robust sensing and activating strategy.
Karwaczynski, Sebastian, Uras, Mehmet H.
Analysis of High-Speed Sideswipe Collisions Using Data from Small Overlap Tests2014-01-04694/1/2014
Little experimental data have been reported in the crash reconstruction literature regarding high-speed sideswipe collisions. The Insurance Institute for Highway Safety (IIHS) conducted a series of high-speed, small overlap, vehicle-to-barrier and vehicle-to-vehicle crash tests for which the majority resulted in sideswipe collisions. A sideswipe collision is defined in this paper as a crash with non-zero, final relative tangential velocity over the vehicle-to-barrier or vehicle-to-vehicle contact surface; that is, sliding continues throughout the contact duration. Using analysis of video from 50 IIHS small overlap crash tests, each test was modeled using planar impact mechanics to determine which were classified as sideswipes and which were not. The test data were further evaluated to understand the nature of high-speed, small overlap, sideswipe collisions and establish appropriate parameter ranges that can aid in the process of accident reconstruction. An example reconstruction of a small overlap, sideswipe collision using optimization methods based on the planar impact mechanics model is included in the paper. The results of the example reconstruction show that the reconstruction method developed in the paper, using the physical evidence and EDR data, produces useful results.
Brach, R. Matthew, Brach, Raymond M., Pongetti, Katherine
Validation of Event Data Recorders in Side-Impact Crash Tests2014-01-05034/1/2014
This study evaluated the accuracy of 75 Event Data Recorders (EDRs) extracted from model year 2010-2012 Chrysler, Ford, General Motors, Honda, Mazda, and Toyota vehicles subjected to side-impact moving deformable barrier crash tests. The test report and vehicle-mounted accelerometers provided reference values to assess the EDR reported change in lateral velocity (delta-v), seatbelt buckle status, and airbag deployment status. Our results show that EDRs underreported the reference lateral delta-v in the vast majority of cases, mimicking the errors and conclusions found in some longitudinal EDR accuracy studies. For maximum lateral delta-v, the average arithmetic error was −3.59 kph (−13.8%) and the average absolute error was 4.05 kph (15.9%). All EDR reports that recorded a seatbelt buckle status data element correctly recorded the buckle status at both the driver and right front passenger locations. For equipped vehicles that reported side torso, side curtain, and frontal airbag deployment information, all vehicles recorded the correct status. Although only model year 2013 and later EDRs must meet Code of Federal Regulations Title 49 Part 563, seatbelt buckle status and frontal airbag deployment time are required data elements.
Tsoi, Ada, Johnson, Nicholas, Gabler, H.
Observations on Pedestrian Pre-Crash Reactions during Simulated Accidents2013-22-000611/11/2013
Pedestrian protection systems, both active and passive systems, are being introduced in the EU and Japan to comply with regulatory requirements. Their designs are specific and, in general, reflect an accident scenario of the pedestrian being struck on the side by a vehicle traveling at a maximum travel speed of 40 kph. The present study is an effort to quantify the effects of pedestrian reaction prior to an accident and identify characteristics that may help minimize or prevent the pedestrian to vehicle interaction. Accident situations were simulated with volunteers using a non-impacting methodology. Fifty one reactions from 23 volunteers of two age groups were observed. Most of the volunteers were found to run, step-back or stop in fright in a dangerous situation. Volunteer speed was an important parameter which could help in differentiating these reactions. Age related differences were also observed, both for reaction strategy and reaction times. While the majority of young subjects ran, elderly stopped as often as they run. Volunteers' posture at the time of impact was found to be highly variable irrespective of the type of reactions. The exception was when a volunteer stopped/braced in apparent fright and raised their arms to form a triangle covering their face and their head. Results of the present study may be helpful when selecting or evaluating the benefit of pedestrian safety strategies by allowing the inclusion of information about types of reaction, pedestrian speed, reaction time and age differences in the scenarios. In addition, pedestrian pre-crash postures and muscle activities could be utilized for evaluating/improving the passive safety systems and active models.
Soni, Anurag, Robert, Thomas, Rongiéras, Frédéric, Beillas, Philippe
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