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Viewing 1 to 30 of 45
2017-03-28
Technical Paper
2017-01-1457
Jingwen Hu, Nichole Ritchie Orton, Rebekah Gruber, Ryan Hoover, Kevin Tribbett, Jonathan Rupp, Dave Clark, Risa Scherer, Matthew Reed
Abstract Among all the vehicle rollover test procedures, the SAE J2114 dolly rollover test is the most widely used. However, it requires the test vehicle to be seated on a dolly with a 23° initial angle, which makes it difficult to test a vehicle over 5,000 kg without a dolly design change, and repeatability is often a concern. In the current study, we developed and implemented a new dynamic rollover test methodology that can be used for evaluating crashworthiness and occupant protection without requiring an initial vehicle angle. To do that, a custom cart was designed to carry the test vehicle laterally down a track. The cart incorporates two ramps under the testing vehicle’s trailing-side tires. In a test, the cart with the vehicle travels at the desired test speed and is stopped by a track-mounted curb.
2017-03-28
Technical Paper
2017-01-1299
Nagurbabu Noorbhasha, Brendan J. O'Toole
Abstract The objective of this research is to design and analyze a roll cage structure for an off-road vehicle that was used for SAE Baja competition by UNLV SAE Baja team. Baja SAE is an intercollegiate competition to design, fabricate, and race a small, single passenger, off-road vehicle powered by a 10 HP Briggs Stratton 4-Stroke gasoline engine. Since the off-road vehicle is powered by a small capacity engine, the weight of the structure is very critical and must be optimized to improve the performance of the vehicle. In an effort to optimize the structure, a finite element analysis (FEA) was performed and the effects of stress and deformation were studied for a linear static frontal impact analysis on roll cage structure. The frame was further modified for structural rigidity. Additional strengthening gussets were added at the locations of high stresses to reduce the stress concentration.
2017-03-28
Technical Paper
2017-01-1425
Brian Jones, Michael Calabro, Justin Brink, Scott Swinford
In minor inline rear-end accidents, vehicle damage is the primary tangible indicator of impact severity or vehicle change in velocity (ΔV). A technique for calculating change in velocity based on vehicle damage for collinear impacts involves application of the Momentum Energy Restitution (MER) method. Offset inline minor rear-end impact testing, wherein minimal vehicle bumper or contact surface engagement occurs, has not been readily published to date. Thus, instrumented offset inline rear-end impacts were performed utilizing a 1997 Ford F-150 Pickup, 1996 Kia Sephia, and 1995 Chrysler LeBaron GTC to determine if the MER method can accurately calculate a vehicle’s ΔV when collinear contact does not occur. Vehicle engagement involved 5.1 cm to 76.2 cm of overlap with impact speeds ranging between 0.7 m/s and 4 m/s.
2017-03-28
Technical Paper
2017-01-1459
HangMook Kim, Jae Kyu Lee, Jin Sang CHUNG
Abstract During a new vehicle development process, there are several requirements for side impact test that should be confirmed. One of the requirements is the prevention of door opening during side impact test. Even though there are many causes for door opening problem, this study deals with inertia effect by impact energy. Until now, there have been two classical methods to prevent car door from opening in side impact. One is the increment of the inertia resistance by increasing the mass of the balance weight and the spring force. The other is the application of the blocking lever. Unfortunately, in spite of our efforts, the door opening problem occurs occasionally. Therefore, to improve the problem fundamentally, this paper proposes a new blocking lever mechanism that work similar to ball-point pen structure. The proposed mechanism fixes the blocking lever when the opening directional inertia force is applied to the door outside handle during side crash.
2017-03-28
Journal Article
2017-01-0112
Mingming Zhao, Hongyan Wang, Junyi Chen, Xiao Xu, Yutong He
Abstract Rear-end accident is one of the most important collision modes in China, which often leads to severe accident consequences due to the high collision velocity. Autonomous Emergency Braking (AEB) system could perform emergency brake automatically in dangerous situation and mitigate the consequence. This study focused on the analysis of the rear-end accidents in China in order to discuss about the parameters of Time–to-Collision (TTC) and the comprehensive evaluation of typical AEB. A sample of 84 accidents was in-depth investigated and reconstructed, providing a comprehensive set of data describing the pre-crash matrix. Each accident in this sample is modeled numerically by the simulation tool PC-Crash. In parallel, a model representing the function of an AEB system has been established. This AEB system applies partial braking when the TTC ≤ TTC1 and full braking when the TTC ≤ TTC2.
2017-03-28
Technical Paper
2017-01-1458
Tack Lam, B. Johan Ivarsson
Abstract Disc herniations in the spine are commonly associated with degenerative changes, and the prevalence increases with increasing age. With increasing number of older people on U.S. roads, we can expect an increase in clinical findings of disc herniations in occupants involved in rear impacts. Whether these findings suggest a causal relationship is the subject of this study. We examined the reported occurrence of all spine injuries in the National Automotive Sampling System - Crashworthiness Data System (NASS-CDS) database from 1993 to 2014. There were over 4,000 occupants that fit the inclusion criteria. The findings in this study showed that, in the weighted data of 2.9 million occupants, the most common spine injury is an acute muscle strain of the neck, followed by strain of the low back. The delta-V of a rear impact is a reliable indicator of the rate of acute cervical strain in occupants exposed to such impacts.
2016-10-25
Technical Paper
2016-36-0227
Ivan R. Begosso, Alex F. Lima, Bruno S. Silva, Danilo M. Lessio, Gilvan P. Rossi, Klemer Santiago
Abstract The trailer hitch is an accessory which has been widely applied to vehicles as a protection device for low speed rear impact, aiming the integrity of the rear fascia. Its installation is commonly made at accessories shops without the orientation of the OEM’s and its project normally does not pursue the integration with vehicle structure. Using Finite Element Method, this work has as objective to study the influence of the trailer hitch in the body structure of small hatchback passenger vehicle during rear impact.
2016-04-05
Technical Paper
2016-01-1458
Ryuta Ono, Wataru Ike, Yuki Fukaya
Abstract Toyota Safety Sense is a safety system package developed to help drivers avoid accident types with a high frequency of occurrence. This paper deals with pre-collision system which forms the core of Toyota Safety Sense, especially Toyota Safety Sense P which uses a combined sensor configuration consisting of a monocular camera paired with millimeter wave radar, in order to achieve both high recognition performance and reliability. The use of a wide-angle monocular camera, millimeter wave radar integrated in the front grill emblem, and a collision determination algorithm for pedestrian targets enabled the development of a pre-collision system comprising detection capability of crossing pedestrians. Toyota has developed warning and pre-collision brake assist for driver to assist in avoiding a collision effectively; In addition, Pre-collision brake has achieved high level of performance for the drivers who cannot avoid a collision.
2016-04-05
Technical Paper
2016-01-1512
Jeya Padmanaban, Roger Burnett, Andrew Levitt
Abstract This paper updates the findings of prior research addressing the relationship between seatback strength and likelihood of serious injury/fatality to belted drivers and rear seat occupants in rear-impact crashes. Statistical analyses were performed using 1995-2014 CY police-reported crash data from seventeen states. Seatback strength for over 100 vehicle model groupings (model years 1996-2013) was included in the analysis. Seatback strength is measured in terms of the maximum moment that results in 10 inches of seat displacement. These measurements range from 5,989 in-lbs to 39,918 in-lbs, resulting in a wide range of seatback strengths. Additional analysis was done to see whether Seat Integrated Restraint Systems (SIRS) perform better than conventional belts in reducing driver and rear seat occupant injury in rear impacts. Field data shows the severe injury rate for belted drivers in rear-impact crashes is less than 1%.
2015-04-14
Technical Paper
2015-01-1472
Roberto Arienti, Carlo Cantoni, Massimiliano Gobbi, Giampiero Mastinu, Mario Pennati, Giorgio Previati
Abstract The lightweight seat of a high performance car is designed taking into account a rear impact, i.e. the crash due to an impulse applied from the rear. The basic parameters of the seat structure are derived resorting to simulations of a crash with a test dummy positioned on the seat. The simulations provide the forces acting at the seat structure, in particular the forces applied at the joint between the seat cushion and the seat backrest are taken into account. Such a joint is simulated as a plastic hinge and dissipates some of the crash energy. The simulations are validated by means of indoor tests with satisfactory results. A tool has been developed for the preliminary design of lightweight seats for high performance cars.
2015-04-14
Technical Paper
2015-01-1414
Jitendra Shah, Mohamed Benmimoun
Abstract The focus of this paper is the threat assessment of perceived threat by drivers in collision avoidance situations. The understanding of the decision making process with regards to the initiation of a driver intervention is a crucial step to gain insight into driver's steering and braking behavior in case of an imminent threat (rear-end collision). Hence a study with various test subjects and a test vehicle has been conducted. The study has helped to understand how drivers behave in potential rear-end collision situations arising from the traffic situation (e.g. start of a traffic jam). This information is of major importance for designing autonomous collision avoidance systems and an important step towards autonomous driving. Autonomous driving in vehicles require system interventions to be initiated as early and safely as possible in order to avoid the collision and to avoid unstable vehicle dynamics situations.
2014-04-01
Technical Paper
2014-01-0524
Stacy M. Imler, Michelle F. Heller, Christine C. Raasch, Heather N. Watson, Ke Zhao
Abstract The risk of sustaining injury in rear impact collisions is correlated to collision severity as well as other factors such as restraint usage. The most recent National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) data available (1997 to 2011) were analyzed to identify accidents involving passenger vehicles that have experienced an impact with a principal direction of force (PDOF) between 5:00 and 7:00, indicating a rear impact collision. The Abbreviated Injury Scale (AIS) was used as an injury rating system for the involved vehicle occupants who were at least sixteen years old and were seated in the outboard seating positions of the front row. These data were further analyzed to determine injury risk based on resultant delta-V and restraint system use. Each body region (head, spine, thorax, abdomen, upper extremity, and lower extremity) was considered separately.
2014-04-01
Technical Paper
2014-01-0492
Lisa P. Gwin, Herbert Guzman, Enrique Bonugli, William Scott, Mark Freund
Abstract There is a paucity of recent data quantifying the injury risk of forces and accelerations that act on the whole body in a back-to-front direction. The purpose of this study was to quantify the level of back-to-front accelerations that volunteers felt were tolerable and non-injurious. Instrumented volunteers were dropped supine onto a mattress, and their accelerations during the impact with the mattress were measured. Accelerometers were located on the head, upper thoracic and lower lumbar regions. Drop heights started at 0.6 m (2 ft) and progressed upward as high as 1.8 m (6 ft) based on the test subjects' consent. The test panel was comprised of male and female subjects whose ages ranged from 25 to 63 years of age and whose masses ranged from 62 to 130 kg (136 to 286 lb). Peak head, upper thoracic and lower lumbar accelerations of 25.9 g, 29.4 g and 39.6 g were measured.
2014-04-01
Technical Paper
2014-01-0437
Rudolf Mortimer, Errol Hoffmann, Aaron Kiefer
Abstract Relative velocity detection thresholds of drivers are one factor that determines their ability to avoid rear-end crashes. Laboratory, simulator and driving studies show that drivers could scale relative velocity when it exceeded the threshold of about 0.003 rad/sec. Studies using accident reconstruction have suggested that the threshold may be about ten times larger. This paper discusses this divergence and suggests reasons for it and concludes that the lower value should be used as a true measure of the psychological threshold for detection of relative velocity.
2013-04-08
Technical Paper
2013-01-0222
Steven Rundell, Allison Guiang, Brian Weaver, Eric G. Meyer
Injury potential to the neck has been studied extensively for rear-end impacts. The capacity for injury to other body regions, such as the lower extremities, has not been previously explored. The objective of the current study was to characterize the forces and motions experienced in the lower extremities during moderate-to-high speed rear-end impacts. The current study utilized publicly available rear-end crash tests. Forty-two 50 km/hour, 20% offset, 180° barrier rear-end impacts were used. The occupant lower extremity behavior was analyzed for 63 ATDs, and included 42 driver's seats, 8 front passenger seats, and 13 right-rear seat scenarios. Three consistent events were identified during each test, in the following sequence; 1. initial compressive femur force, 2. secondary tensile femur force, and 3. rearward pelvis acceleration peak.
2013-04-08
Technical Paper
2013-01-0793
Eric Deyerl, Louis Cheng, Jordan Gatti
A commercially-available two-dimensional software program, validated to model high speed collisions, was extended to analyze rear-end collisions involving speed changes below 10 miles per hour. Simulation results were compared to the results of several series of published full-scale staged collisions. A total of 84 rear-end crash tests, involving 20 vehicles of different makes and models, were analyzed. Test conditions included free-rolling as well as braked vehicles, and in-line as well as oblique collision configurations. The analysis demonstrates that the simulation model provides accurate and reliable predictions of vehicle delta-V's for rear-end collisions, under aligned and oblique conditions, and with free-rolling and braked conditions for the foam core and piston-equipped bumper types examined.
2013-04-08
Technical Paper
2013-01-0660
Pengxiang Wang
The whiplash disorders are associated with huge costs for society. The BioRID (Biofidelic Rear Impact Dummy) dummy and the test procedure are developed to ensure the seat systems optimized to reduce the risk of injury in low-severity rear-end collisions. This paper discussed the BioRID dummy spine structure and calibration procedures. It is found during the dynamic calibration it is very difficult to keep the head neck OC (Occipital Condyle) joint in the static corridor and different head position will obtain the different score in the EuroNCAP whiplash Seat Assessment. A proposal is developed to control the OC joint in the dynamic calibration to ensure the whiplash test can be conducted correctly.
2013-04-08
Technical Paper
2013-01-0221
Nicholas Yang, Tack Lam, David Dainty, Edmund Lau
Volunteer subject studies in low speed rear impacts have shown that significant lumbar spine injuries are unlikely in such collisions. Anthropomorphic test devices (ATD) used in low to medium speed rear impact simulations have similarly revealed an unlikely mechanism to cause lumbar spine injuries. However, low back complaints after rear impacts are common in clinical practice. We attempt here to determine the incidence of lumbar spine injuries from actual field data which may provide an insight into the apparent paradox between experimental data and clinical practice. We examined the incidence of all spine injuries in the NASSCDS (National Automotive Sampling System - Crashworthiness Data System) database from 1993 to 2009. We limited the data to only look at rear-end crashes involving two vehicles.
2013-03-25
Journal Article
2013-01-0124
Shintaro Saigo, Pongsathorn Raksincharoensak, Masao Nagai
Recently, a number of researches on detecting such inattentive driving have been carried out, and various detection methods have been proposed. In this paper, using driving data which can be measured with existing on-board vehicle sensors, the authors focus on headway distance behavior which relates to rear-end collision as well as the steering behavior which can be used to detect driver drowsiness. The emphasis of this study is that the inattentive driving can be potentially detected from the driving behavior deviated from the normative characteristics considering the transfer function from the environment to the driving operation. Therefore, intrusive measurement methods such as physiological measurement are not required. In addition, to detect the inattentive state by the criterion of the individual driver, the driver assistance system can be realized in the way that it can be adapted not only to various types of drivers, but also to the driver real-time driving state.
2012-10-29
Technical Paper
2012-22-0005
Kevin Moorhouse, Bruce Donnelly, Yun-Seok Kang, John H Bolte IV, Rodney Herriott
The goal of this study is to evaluate both the internal and external biofidelity of existing rear impact anthropomorphic test devices (BioRID II, RID3D, Hybrid III 50th) in two moderate-speed rear impact sled test conditions (8.5g, 17 km/h; 10.5g, 24 km/h) by quantitatively comparing the ATD responses to biomechanical response targets developed from PMHS testing in a corresponding study. The ATDs and PMHS were tested in an experimental seat system that is capable of simulating the dynamic seat back rotation response of production seats. The experimental seat contains a total of fourteen load cells installed such that external loads from the ATDs and PMHS can be measured to evaluate external biofidelity. The PMHS were instrumented to correspond to the instrumentation contained in the ATDs so that direct comparison between ATDs and PMHS could be made to evaluate internal biofidelity.
2012-04-16
Technical Paper
2012-01-0273
Brian N. Fildes
The aim of this study was to assess the crash injury benefits of an Automatic Emergency Braking System (AEBS), for the passenger vehicle population in France. These benefits were examined in regards to the number/proportion of fatalities and serious injured crashes that could be saved per annum. The two crash types investigated included pedestrian crashes and rear-end collisions. AEBS was expected to intervene 0.6sec prior to the crash and at published levels of force according to whether braking previously occurred and the road condition/surface adherence. The analysis involved national crash data, BAAC, collected by the French Ministry of transport, in-depth crash data made available from the European EACS (European Accident Causation Survey) database by LAB, as well as findings from the U.S. NASS/CDS and NHTSA PCDS in-depth databases. A step-wise methodology was used to calculate the crash injury benefits of AEBS across the two crash types.
2012-04-16
Technical Paper
2012-01-0601
Daniel Fittanto, Kathleen Allen Rodowicz
Evaluation of vehicle impacts may involve the use of computer simulations. While simulation programs with two-dimensional impact models have been used for decades, more recent three-dimensional impact models have been developed. This research compares DyMESH, the three-dimensional vehicle impact model in HVE-SIMON, with full-scale vehicle crash tests involving low-speed rear impacts. Exponent Failure Analysis Associates (Phoenix, Arizona) conducted rear impact research involving two virtually identical 1983 Nissan Pulsar NX 2-door vehicles. One vehicle was stationary, while the second vehicle impacted the rear of the first vehicle in an aligned configuration. Tests were run at impact speeds ranging from 5 to 20 MPH. Tri-axial accelerometers were positioned in both vehicles and vehicle acceleration and velocity responses were recorded. SIMON-DyMESH was used to simulate these impact tests. DyMESH utilizes a mesh shell determined by the three-dimensional geometry of the vehicle.
2011-11-07
Technical Paper
2011-22-0005
Philippe Petit, Carole Luet, Pascal Potier, Guy Vallancien
Occupant protection in rear impact involves two competing challenges. On one hand, allowing a deformation of the seat would act as an energy absorber in low severity impacts and would consequently decrease the risk of neck injuries. However, on the other hand, large deformations of the seat may increase the likelihood of occupant ejection in high severity cases. Green et al., 1987 analyzed a total of 919 accidents in Great Britain. They found that occupant ejection resulted in a risk of severe injuries and fatalities between 3.6 and 4.5 times higher than those cases where no ejection was observed. The sample included single front, side and rear impacts as well as multiple impacts and rollover. The rate of belt use in the sample was 50%. While this analysis included all forms of impact scenarios, nevertheless, it highlights the relative injury severity of occupant ejection.
2011-04-12
Technical Paper
2011-01-0271
Rami Mansour, Douglas Romilly
Rear end collisions account for approximately $9 billion annually in the United States alone. These types of collisions account for nearly 30% of all vehicle impacts making them the most common type. Soft tissue injury to the neck (i.e. “whiplash”) is typically associated with this type of collision due to the occupant dynamics of the passengers in the struck vehicle. At low relative impact velocities, whiplash-type injuries are known to occur but are typically attributed to: 1) improper seat adjustment, 2) an “out-of-position” event, or 3) a low injury threshold due to age, gender, etc. In high impact collisions, both whiplash and occupant ejection can take place, the latter placing far greater risk of injury not only to the front seat occupant, but also to any rear seat passengers as well. The automobile seating system is the predominant safety device employed to protect the occupant during these types of collisions.
2011-04-12
Technical Paper
2011-01-0276
Si-Woo Kim, So-Jung shim, Myung-Won Suh
A large study of rear-end collisions was conducted for the neck injury indicators and test procedures. Neck injury in low-speed rear-end collisions is a big issue because there are a lot of patients despite low-speed rear-end collisions. Europe, Korea and Japan introduced the specific part in the New Car Assessment Program to reduce whiplash injury in low-speed rear-end collisions. From the legal point of view, to reduce the frequency and severity of injuries caused by rearward displacement of the head in rear-end collision, USA, EC, Korea, Japan and others internationally cooperated to make the global technical regulation (GTR) in UNECE/WP29. In 2008, after much meandering, GTR No. 7 head restraints were established. However the GTR No.7 is not a unique regulation because many countries had their own opinions and domestic regulations, and many questions related to injury criteria and biomechanical issues of dummy remain unresolved.
2011-04-12
Journal Article
2011-01-0273
Jeffrey Braganza, Massoud S. Tavakoli, Janet Brelin-Fornari
The rear seat occupant has been the subject of an increasing number of research efforts in recent years. However, the majority of the research has focused on frontal impact, while there are also a number of studies concerned with low to moderate delta-V rear impact. Very limited work exists regarding the fate of the rear seat occupant involved in high-severity rear impact, especially when utilizing the BioRID anthropomorphic test device (ATD). Furthermore, it is evident that the out of position rear occupant, as defined by leaning forward prior to rear impact, is also of relevance to this line of research. The objective of this study is to explore and compare the response of BioRID and 50 th percentile Hybrid III in conjunction with the effects of head restraint geometry and the occupant seating configuration (normal seating versus forward leaning) in high-severity rear impact tests.
2011-04-12
Technical Paper
2011-01-0274
David C. Viano
Purpose: This study presents cases of fracture-dislocation of the thoracic spine in extension during severe rear impacts. The mechanism of injury was investigated. Methods: Four crashes were investigated where a lap-shoulder-belted, front-seat occupant experienced fracture-dislocation of the thoracic spine and paraplegia in a severe rear impact. Police, investigator and medical records were reviewed, the vehicle was inspected and the seat detrimmed. Vehicle dynamics, occupant kinematics and injury mechanisms were determined in this case study. Results: Each case involved a lap-shoulder-belted occupant in a high retention seat with ≻1,700 Nm moment or ≻5.5 kN strength for rearward loading. The crashes were offset rear impacts with 40-56 km/h delta V involving under-ride or override by the impacting vehicle and yaw of the struck vehicle. In each case, the occupant's pelvis was restrained on the seat by the open perimeter frame of the seatback and lap belt.
2011-04-12
Technical Paper
2011-01-0203
Steve Thorne, Bruce W. Leppla
ACC radar systems gather valuable data about the speed of forward vehicles, and then utilize that information to best regulate the spacing between those forward vehicles and the ACC host. However, such radar-gathered data can also be useful to help prevent rear-end collisions involving the host vehicle. Embedded in that data is information revealing decelerations of forward vehicles that holds particular value to any driver that might be trailing the host vehicle - especially if their vision is screened by the bulk of the host vehicle. In this paper, a hybrid stop lamp system is proposed whereby ACC radar data gathered by a host vehicle is automatically conveyed to the trailing driver utilizing a new light element integrated with the host vehicle's stop lamp system.
2011-04-12
Journal Article
2011-01-0579
Eric Raphael, Raymond Kiefer, Pini Reisman, Gaby Hayon
Forward Collision Alert (or Forward Collision Warning) systems provide alerts intended to assist drivers in avoiding or mitigating the harm caused by rear-end crashes. These systems currently use front-grille mounted, forward-looking radar devices as the primary sensor. In contrast, Lane Departure Warning (LDW) systems employ forward-looking cameras mounted behind the windshield to monitor lane markings ahead and warn drivers of unintended lane violations. The increasing imaging sensor resolution and processing capability of forward-looking cameras, as well recent important advances in machine vision algorithms, have pushed the state-of-the-art for camera-based features. Consequently, camera-based systems are emerging as a key crash avoidance system component in both a primary and supporting sensing role. There are currently no production vehicles with cameras used as the sole FCA sensing device.
2011-04-12
Technical Paper
2011-01-0544
Dinesh Mana, Dhanendra Nagwanshi, Matthew Marks, Arunachala P
High repair cost and the subsequent increase in insurance cost in a highly competitive automobile market have forced every automobile original equipment manufacturer (OEM) to comply with the FMVSS and ECE-42 regulatory requirements of low-speed vehicle damageability. Although, the terminologies used are different, similar regulatory requirements also exist in Asia-pacific region. At the rear side, reducing the damage to expensive vehicle components in a low-speed pendulum impact or a low-speed barrier impact can attain a good rating for low-speed vehicle damageability. This paper focuses on a detailed study of various lightweight plastic rear beam designs and their effectiveness in reducing the damage to the vehicle during low-speed vehicle-to-vehicle collision or vehicle to barrier collision.
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