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2010-04-12
Journal Article
2010-01-0379
Guofei Chen, Todd Link, Ming Shi, Tau Tyan, Ruth Gao, Paul McKune
To improve the energy absorption capacity of front-end structures during a vehicle crash, a novel 12-sided cross-section was developed and tested. Computer-aided engineering (CAE) studies showed superior axial crash performance of the 12-sided component over more conventional cross-sections. When produced from advanced high strength steels (AHSS), the 12-sided cross-section offers opportunities for significant mass-savings for crash energy absorbing components such as front or rear rails and crush tips. In this study, physical crash tests and CAE modeling were conducted on tapered 12-sided samples fabricated from AHSS. The effects of crash trigger holes, different steel grades and bake hardening on crash behavior were examined. Crash sensitivity was also studied by using two different part fabrication methods and two crash test methods. The 12-sided components showed regular folding mode and excellent energy absorption capacity in axial crash tests.
2010-04-12
Journal Article
2010-01-0380
Shun Yi Jin, William J. Altenhof
Quasi-static axial cutting of AA6061-T6 and T4 round extrusions were completed using a specially designed cutter with multiple blades. The round specimens had a length of 200 mm, a nominal outer diameter of 50.8 mm, and a wall thickness of 3.175 mm or 1.587 mm. Four different cutters, constructed from heat-treated 4140 steel, having 3, 4, 5 and 6 blades on each cutter with a nominal tip width of 1.0 mm were used to penetrate through the round extrusions. A clean cutting mode was observed for the AA6061-T6 and T4 extrusions with wall thickness of 3.175 mm with an almost constant steady state cutting force. A braided cutting mode was observed for extrusions with both tempers with wall thickness of 1.587 mm, which resulted in a slightly oscillating steady state cutting force. For all extrusions with a wall thickness of 3.175 mm, the steady state cutting force increased with an increase in the number of cutter blades.
2010-04-12
Journal Article
2010-01-0383
Garrett W Wood, Matthew B Panzer, Cameron R Bass, Barry S Myers
The biofidelity of the Hybrid III headform in impact is largely dependent on local head geometry and viscoelastic mechanical properties of its polymer skin. Accordingly, for accurate simulation of the ATD headform in computational models, a quantitative understanding of the mechanical properties of skin material is required at a variety of strain rates and strain amplitudes. The objective of this study was to characterize the head skin material of the Hybrid III test dummy for finite deformations and at moderate strain rates for blunt impact simulation using finite element models Head skin material from a single ATD was tested using uniaxial compression. A viscoelastic constitutive model with separable temporal and elastic responses was used to characterize the nonlinear and viscoelastic material behavior.
2010-04-12
Journal Article
2010-01-0516
Michelle F. Heller, William N. Newberry, Janine E. Smedley, Senthil K. Eswaran, Jeffrey J. Croteau, Michael R. Carhart
Rollover events involving multiple revolutions are dynamic, high-energy, chaotic events that may result in occupant injury. As such, there is ongoing discussion regarding methods that may reduce injury potential during rollovers. It has been suggested that increasing a vehicle's roof strength will mitigate injury potential. However, numerous experimental studies and published field accident data analyses have failed to show a causal relationship between roof deformation and occupant injury. The current study examines occupant kinematics and injury mechanisms during dolly rollover testing of a vehicle with a high roof strength-to-weight ratio (SWR = 4.8). String potentiometers and high-speed video cameras were used to capture and quantify the dynamic roof motion throughout the rollover. Instrumented Anthropomorphic Test Devices (ATDs) in the front occupant positions allowed for the assessment of occupant kinematics, loading, and injury mechanics during the rollover event.
2011-04-12
Journal Article
2011-01-0581
R. Michael Van Auken, John W. Zellner, Jordan Y. Silberling, Joseph Kelly, Dean P. Chiang, Peter Broen, Amanda Kirsch, Yoichi Sugimoto
The Advanced Crash Avoidance Technologies (ACAT) program initiated by the National Highway Traffic Safety Administration had two major overall objectives. These were to develop a standardized Safety Impact Methodology (SIM) tool to evaluate the effectiveness of advanced technologies in avoiding and mitigating specific types of vehicle crashes; and to develop and demonstrate objective tests that are used in the SIM to verify the safety impact of a real system. Honda and Dynamic Research Inc. (DRI) had been developing and applying such SIMs for several years and had a Cooperative Agreement with NHTSA to further develop a SIM in order to determine the feasibility of developing estimates of effectiveness for specific not-yet-deployed safety technologies in the absence of data from real world or field operational tests, and linking it to the results from objective tests.
2011-04-12
Journal Article
2011-01-0580
Joseph Kelly, Peter Broen, Jordan Silberling, Nenad Bozin, John Zellner
As Advanced Crash Avoidance Technologies (ACATs) such as Forward Collision Warning (FCW), Crash Imminent Braking Systems and other advanced technologies continue to be developed, the need for full-scale test methodologies which can minimize hazards to test personnel and damage to equipment has rapidly increased. The challenge of evaluating such ACAT systems is twofold. First, the evaluation system must be able to deliver a potential Collision Partner (CP) reliably and precisely along a trajectory which would ultimately result in a crash in a variety of configurations, such as rear-ends, head-ons, crossing paths, and sideswipes. Second, and more importantly, the collision partner must not pose a substantial physical risk to the test driver, other test personnel, equipment, or to test vehicles in the event that the collision is not avoided.
2011-04-12
Technical Paper
2011-01-0590
Timothy Hsu, Guy Nusholtz
One method of reducing the number and/or severity of vehicle crashes is to warn the driver of a potential crash. The theory is that there will be driving conditions in which the drivers are unaware of a potential crash and a warning system will allow them to, in some manner, avoid the accident or reduce the severity. In an attempt to develop an analytical understanding of Forward Collision Warning systems (FCW) for frontal impacts a 2-d mathematical/kinematic model representing a set of pre-crash vehicle dynamic maneuvers has been built. Different driving scenarios are studied to explore the potential improvement of warning algorithms in terms of headway reduction and minimization of false alarm rates. The results agree with the field data. NHTSA's new NCAP active safety criteria are evaluated using the model. The result from the analysis indicates that the NHTSA criteria may drive higher false alarm rates. Opportunities of minimizing false positive rates are discussed.
2011-04-12
Journal Article
2011-01-0588
Laura Stanley, Linda Angell, Richard Deering, Miguel Perez, Charles Green, Robert Llaneras
An analysis of the first 35 back-over crashes reported by NHTSA's Special Crash Investigations unit was undertaken with two objectives: (1) to test a hypothesized classification of backing crashes into types, and (2) to characterize scenario-specific conditions that may drive countermeasure development requirements and/or objective test development requirements. Backing crash cases were sorted by type, and then analyzed in terms of key features. Subsequent modeling of these SCI cases was done using an adaptation of the Driving Reliability and Error Analysis Methodology (DREAM) and Cognitive Reliability and Error Analysis Methodology (CREAM) (similar to previous applications, for instance, by Ljung and Sandin to lane departure crashes [10]), which is felt to provide a useful tool for crash avoidance technology development.
2011-04-12
Technical Paper
2011-01-0541
Mahmoud Yousef Ghannam, Todd Clark, Yeruva Reddy, Jinkoo Lee
This work presents a study of crash energy and severity in frontal offset Vehicle-To-Vehicle (VTV) crash tests. The crash energy is analyzed based on analytical formulations and empirical data. Also, the crash severity of different VTV tests is analyzed and compared with the corresponding full frontal rigid barrier test data. In this investigation, the Barrier Equivalent Velocity (BEV) concept is used to calculate the initial impact velocity of frontal offset VTV test modes such that the offset VTV tests are equivalent to full frontal impact tests in terms of crash severity. Linear spring-mass model and collinear impact assumptions are used to develop the mathematical formulation. A scale factor is introduced to account for these assumptions and the calculated initial velocity is adjusted by this scale factor. It is demonstrated that the energies due to lateral and rotational velocity components are very small in the analyzed frontal VTV tests.
2011-04-12
Technical Paper
2011-01-0543
Dale E. Halloway, James Saunders, Narayan Yoganandan, Frank Pintar
The purpose of the study was to identify all small overlap impacts using published coded NASS-CDS data. Three sets of criteria were used: CDC measurements; crush profiles for frontal impacts; and crush profiles for oblique side impacts to the fender component. All criteria were applied to passenger and non-passenger cars and their different vehicle class sizes. Data were analyzed based on fatalities and different levels of MAIS trauma. The overall data set based on CDC codes for 2005 to 2008 NASS-CDS data had 9,206 MAIS=0; 13,522 MAIS=1-2; 3,600 MAIS=3-6; 1,092 MAIS=7; and 961 fatal cases. For the weighted ensemble, these data were: 5,800,295; 4,324,773; 269,042; 219,481; and 44,906 cases, respectively. However, these cases reduced to 1071, 1468, 364, 82, and 87 raw cases with the application of the CDC criteria for frontal impacts.
2013-11-11
Technical Paper
2013-22-0004
Stephen W. Rouhana, Srinivasan Sundararajan, Derek Board, Priya Prasad (Retired), Jonathan D. Rupp, Carl S. Miller, Thomas A. Jeffreys, Lawrence W. Schneider
NHTSA estimates that more than half of the lives saved (168,524) in car crashes between 1960 and 2002 were due to the use of seat belts. Nevertheless, while seat belts are vital to occupant crash protection, safety researchers continue efforts to further enhance the capability of seat belts in reducing injury and fatality risk in automotive crashes. Examples of seat belt design concepts that have been investigated by researchers include inflatable, 4-point, and reverse geometry seat belts. In 2011, Ford Motor Company introduced the first rear seat inflatable seat belts into production vehicles. A series of tests with child and small female-sized Anthropomorphic Test Devices (ATD) and small, elderly female Post Mortem Human Subjects (PMHS) was performed to evaluate interactions of prototype inflatable seat belts with the chest, upper torso, head and neck of children and small occupants, from infants to young adolescents.
2013-04-08
Technical Paper
2013-01-0467
Robert Rucoba, Robert Liebbe, Amanda Duran, Lee Carr
Tire failures, including tread belt detachments, have been associated with loss of control crashes including rollovers. Numerous reasons exist for control loss including forces created by the failed or failing tire, cornering capacity diminishment for the detreaded tire combined with control demands beyond the remaining capacity of the vehicle and inappropriate driver demands including excessive steering. Extensive studies have been completed to define the various causes of control loss and to identify risk-reducing countermeasures. These studies have included reconstructions of crashes and tests of real vehicles in test track environments with tires purposely caused to fail.
2004-03-08
Technical Paper
2004-01-0335
Madana Gopal, Ken Baron, Minoo Shah
Automotive rollover is a complex mechanical phenomenon. In order to understand the mechanism of rollover and develop any potential countermeasures for occupant protection, efficient and repeatable laboratory tests are necessary. However, these tests are not well understood and are still an active area of research interest. It is not always easy or intuitive to estimate the necessary initial and boundary conditions for such tests to assure repeatability. This task can be even more challenging when rollover is a second or third event (e.g. frontal impact followed by a rollover). In addition, often vehicle and occupant kinematics need to be estimated a-priori, first for the safe operation of the crew and equipment safety, and second for capturing and recording the event. It is important to achieve the required vehicle kinematics in an efficient manner and thus reduce repetitive tests. Mathematical modeling of the phenomenon can greatly assist in understanding such kinematics.
2004-03-08
Technical Paper
2004-01-0340
M. Kröninger, R. Lahmann, T. Lich, M. Schmid, H. Güttler, T. Huber, K. Williams
This paper describes a new system for early detection of tripped rollover crashes. The main goal of this system is to improve the protection of restraint devices, such as curtain window bags, in these rollover situations. This is achieved by a new rollover sensing (RoSe) algorithm in the airbag controller which produces a very early and robust deployment decision. Based on the analysis of tripped rollover test data, this paper shows how improved rollover sensing performance can be achieved by considering information about the vehicle's driving state before the rollover occurs. The results of this new approach are discussed in terms of deployment times. Finally a combined active and passive safety system architecture for the realization of the approach is suggested.
2004-03-08
Technical Paper
2004-01-0341
Hermann Steffan, Andreas Moser
Due to the increasing number of minivans and sport utility vehicles, rollovers have become more significant. As a result, various accident reconstruction programs have been developed to address this issue. To reconstruct rollover crashes, various requirements have to be fulfilled. These consist of: providing a simple method that is able to model three dimensional environments that often play a major role in rollovers. including suspension, tire and collision models must be provided. This is particularily important in the rollover initiation phase. including proper vehicle geometry and contact stiffness must be available. These are important for simulation of body contacts that affect the vehicle motion. This study focuses on one program, PC-CRASH. This program was developed to allow simulations of vehicle 3-dimensional movements before, during and after the impact. The study also discusses the physical background of the models, their capabilities as well as their limitations.
2004-03-08
Technical Paper
2004-01-0342
David C. Viano, Chantal S. Parenteau
This paper provides an overview of rollover crash safety, including field crash statistics, pre- and rollover dynamics, test procedures and dummy responses as well as a bibliography of pertinent literature. Based on the 2001 Traffic Safety Facts published by NHTSA, rollovers account for 10.5% of the first harmful events in fatal crashes; but, 19.5% of vehicles in fatal crashes had a rollover in the impact sequence. Based on an analysis of the 1993-2001 NASS for non-ejected occupants, 10.5% of occupants are exposed to rollovers, but these occupants experience a high proportion of AIS 3-6 injury (16.1% for belted and 23.9% for unbelted occupants). The head and thorax are the most seriously injured body regions in rollovers. This paper also describes a research program aimed at defining rollover sensing requirements to activate belt pretensioners, roof-rail airbags and convertible pop-up rollbars.
2004-03-08
Technical Paper
2004-01-0343
Peter J. Schubert, David Nichols, Edward J. Wallner, Henry Kong, Jan K. Schiffmann
Rollover sensing and discrimination generally requires an algorithm that monitors vehicle motion and anticipates conditions that will lead to a rollover. In general, a deploy command is required in a time frame such that safety measures can be activated early enough to protect the occupants. A rollover discrimination system will typically include internal motion sensors, vehicle signals from other on-board sensors, and a microprocessor to execute the deployment algorithm. A supplemental signal path is used to arm the system, making it less susceptible to single point component failures. In this chapter we explore basic concepts of rollover sensors and system mechanization, rollover discrimination algorithms, and arming methodology. A simulation environment that models the performance of the system across part tolerance, temperature extremes and component age is used to estimate the scope of expected discrimination performance in the field.
2004-03-08
Technical Paper
2004-01-0346
Mary L. Chipman, Bhagwant Persaud, John Bou-Younes, Ian Hale, Ravi Bhim
Side impact crashes account for 25-40% of all crashes, and a high proportion of those involving personal injury. The only driver factor consistently implicated in crash occurrence in the literature is being older, so that vehicle and environmental factors are of primary importance for crash prevention. Crash investigations conducted in Toronto of passenger vehicles in two-vehicle side-impact crashes were included. Control data, obtained at the crash site close to the crash date on the same weekday and time of day, included license numbers of up to four passing vehicles for each vehicle involved in the crash. From the license number we obtained the make, model, year, curb weight, dimensions and safety equipment such as airbags, ABS and traction control. Descriptive and comparative analyses of the crashes were conducted to identify characteristics of crash-involved vehicles relative to control vehicles.
2004-03-08
Technical Paper
2004-01-0348
Chen Xiaodong, Lin Haiyan, Ge Ruhai, You Guozhong, Luo Yan, Shi Guangkui, Zhu Xichan
Now, crash simulation has brought remarkable advances using the finite element method for evaluating vehicle crashworthiness and occupant protection. In accordance with the first full-scale side impact test in China, the finite element model of CHERY side crash simulation including CHERY car, Moving Deformable Barrier (MDB), and EuroSID-I dummy is modeled using nonlinear finite element analysis program visual proving ground (VPG) of engineer technology associate (ETA), inc. The results of simulation show excellent correlation with the test data, which provides the confidence of the simulation prediction. Finally, mend application for vehicle side crashworthiness is evaluated using the side impact model.
2004-03-08
Technical Paper
2004-01-0350
Suzanne Tylko, Dainius Dalmotas
The responses of a 5th percentile female ATD in the driver and/or rear passenger positions of 56 crashes are described. The Transport Canada side impact programme consisted of LTV-to-car impacts, car-to-car impacts and IIHS barrier-to-car tests. The majority of the tests involved severe crash conditions for which the vehicles were not designed. The SID-IIs head, chest and abdominal responses were compared to determine the effects of the striking bullet geometry, the angle of impact, the impact point and the self-protective elements of the struck vehicle, including airbag technology and armrest designs. The SID-IIs head responses and deflection measures were sufficiently sensitive to discriminate between the various striking vehicles, crash configurations, airbag systems and armrest characteristics.
2004-03-08
Technical Paper
2004-01-0842
Jeffrey Augenstein, Elana Perdeck, James Stratton, Luis Labiste, Jerry Phillips, Jeffrey Mackinnon, Kennerly Digges, Richard Morgan, George Bahouth
The U.S. Department of Transportation-sponsored Crash Injury Research and Engineering Network (CIREN) program offers a reasonable look at the efficacy of second-generation air bags. This paper examines the data from the William Lehman Injury Research Center (WLIRC). The WLIRC data is a near census of crashes in the Miami-Dade region with occupants that appear to be severely injured. The percentage of deaths among trauma patients in the WLIRC data as a function of delta-V for first-generation air bags was higher than expected at lower delta-V's. There were nine driver fatalities at delta-V's of less than 20 mph (four involving short stature occupants, four with elderly occupants, and one due to significant intrusion and/or vehicle incompatibility). The data supported NHTSA's conclusion that first-generation air bags were too aggressive for occupants in close proximity to the deploying air bag and too aggressive for older persons.
2004-03-08
Technical Paper
2004-01-0852
Anne W. Snowdon, Jan Miller-Polgar, James Potvin, Giovanna Follo
Since 1976, Ontario has legislated mandatory use of vehicle restraints. However, trauma due to vehicle collisions continues to be a leading cause of death and injury in children. A survey design was used to examine parental knowledge and perceptions about safety systems for children. A biomechanical observation was conducted to document the physical and cognitive demands associated with safety restraint use. Results suggest that most children are generally seated in the correct restraint system; however transitions from forward facing car seats to booster seats and/or lap and shoulder belts were often done too early. In addition, physical demands of using safety restraints exceed most parents' ability to safety install and use safety restraints for their children.
2004-03-08
Technical Paper
2004-01-1214
Craig C. Wilkinson, Jonathan M. Lawrence, Bradley E. Heinrichs, Gunter P. Siegmund
Crash data recorded by the restraint control module (RCM) installed in newer Ford passenger vehicles have recently become available to investigators. To quantify the accuracy of the crash data in low-speed collisions, two RCM-equipped vehicles were exposed to 84 aligned frontal barrier collisions with speed changes up to 13.5 km/h. The accuracy of the speed change reported by the RCM ranged from an underestimate of 1.8 km/h to an overestimate of 0.3 km/h. The error varied with speed change. The RCMs were mounted on a linear sled to investigate their sensitivity to specific collision pulse parameters. For both RCMs, the first eight acceleration data points were duplicated at the end of the data and the record of the crash pulse was often incomplete. Based on the results of this study, crash investigators need to carefully interpret the RCM-reported acceleration and speed change data before using it to reconstruct low-speed collisions involving Ford vehicles.
2004-03-08
Technical Paper
2004-01-1210
Nicholas J. Durisek, C. Brian Tanner, H. Fred Chen, Dennis A. Guenther
The shape of an acceleration pulse in an impact is not only affected by the change in velocity, but also by the geometry and stiffness of the both the striking vehicle and the struck object. In this paper, the frontal crash performance of a full-size pickup is studied through a series of impact tests with a rigid pole and with a flat barrier. Each rigid pole test is conducted at one of four locations across the front of the vehicle and at impact speeds of 10 mph, 20 mph, or 30 mph. The flat barrier tests are conducted at 10 mph, 15 mph, 20 mph, and 30 mph. The vehicle crush and acceleration pulses resulting from the pole tests are compared to those resulting from the barrier tests. The severity of pole impacts and the severity of flat barrier impacts are compared based on peak accelerations and pulse durations of the occupant compartment.
2004-03-08
Technical Paper
2004-01-1222
Scott Kimbrough
Monte Carlo simulation is used to determine the likelihoods of competing scenarios offered by opposing parties involved in a motor vehicle accident. A case study is presented in which there is a dispute among the parties about who passed who first. It is shown that even though both scenarios are possible, one of the scenarios has a much greater likelihood. Besides demonstrating how Monte Carlo simulation provides probability information that can be used to weigh the likelihood of competing scenarios, the case study also provides another example of how Monte Carlo simulation can dig information out of the evidence surrounding an accident that cannot be obtained by other methods.
2004-03-08
Technical Paper
2004-01-1220
Albert G. Fonda
This paper continues a previous study of the effects of uncertainty of measurement upon accident reconstruction. The task is to identify, given the many inevitable errors of observation, the few of greatest import, so that these errors may be reduced, and to document the accuracy of the associated reconstruction. Until recently, it was not for lack of method that such studies could not be properly performed, but for lack of good data on uncertainty of measurement. The essential data was provided in 2002 in a report by Bartlett and others of juried studies performed by volunteer field investigators, summarized and supplemented in 2003 by Bartlett and Fonda in the form of a single table of all likely errors of measurement (furnished again here). In that paper, Finite Difference Analysis (FDA) was reviewed and with the aid of the new data was applied to automotive accident reconstruction.
2004-03-08
Technical Paper
2004-01-1193
Herbert M. Guzman, Whitman E. McConnell, Darrin A. Smith
The vehicle dynamics of non-collinear, low-velocity front-to- rear collisions have received little formal study. The twenty-three angled collisions conducted for this project revealed significant vehicle dynamic differences when compared with similar-energy collinear rear-end collisions. Two recent model year vehicles were used to conduct non-collinear collisions at a nominal 12 km/h impact velocity. The pre-collision angles between the test vehicles were established so that the striking vehicle's line of action through its CG was either 15 or 30 degrees from the stationary struck vehicle's initial heading. Both vehicles had accelerometers at their CG's measuring longitudinal and lateral accelerations. The struck vehicle also had sensors to measure CG vertical accelerations, yaw rates, and longitudinal and lateral velocities. Film from three high-speed 16-mm [film] cameras was digitized and analyzed for each collision. The ΔV at various points within the struck vehicle was studied.
2004-03-08
Technical Paper
2004-01-1195
Thomas F. Fugger, Bryan C. Randles, Jerry J. Eubanks
Recent models of General Motors (GM) and selected Ford vehicles may be equipped with an event data recorder (EDR) that records information in the airbag sensing and diagnostic module (GM-SDM) or restraint control module (Ford-RCM). These systems have become a resource to the accident reconstructionist in the analysis of collisions involving data recorder equipped vehicles, as typically the data can be downloaded via the Vetronix Crash Data Retrieval (CDR) System. The purpose of this paper is to investigate the use of the CDR System in pedestrian accidents. A series of impacts using a pedestrian dummy and SDM equipped vehicles were performed. After each test, the SDM was downloaded via the CDR system and the data evaluated. The dummy and vehicle kinematics were documented and the vehicle impact response was compared with the SDM recorded velocity change and impact speed.
2004-03-08
Technical Paper
2004-01-1181
Nathan A. Rose, Stephen J. Fenton, Richard M. Ziernicki
This paper examines the validity of the effective mass concept used in the CRASH 3 damage analysis equations. In this study, the effective mass concept is described, the simplifying assumptions that it entails are detailed, and the accuracy of the concept is tested by comparing ΔVs calculated from the CRASH 3 equations to results of numerical simulations with a non-central impact model. This non-central impact model allowed the effective mass concept to be tested in isolation from other assumptions of the CRASH 3 program. The results of this research have shown that the effective mass concept accurately models the effects of collision force offset when certain conditions are met. These conditions are discussed, along with their implications for damage interpretation. This paper also presents an analytic expression that relates damage energy to closing speed (initial relative velocity) for the general case of non-central collisions.
2004-03-08
Technical Paper
2004-01-1319
Joseph M. Nolan, Matthew Brumbelow, David S. Zuby, Matthew Avery
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