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Viewing 271 to 300 of 15812
Technical Paper
2014-04-01
Donald Parker, John Zolock, Richard Keefer
Studies of rollover accidents have reported crash attributes such as the number of rolls, rollout distance, initial over-the-ground speed, average roll rate, average over-the-ground deceleration, magnitude of roof deformation, cumulative damage, time and post-crash headroom. While these more general attributes are related to the repeated vehicle-to-ground impacts during a rollover, it has been previously shown [1] that a specific ground impact during a rollover and its consequences can be studied in more detail by using its acceleration time history (crash pulse or impulse) and energy loss. These two quantities are particularly meaningful to use when studying impact mechanics, however, they are limited to circumstances where the data exists, which means real-world on-road crashes cannot be used directly. Acceleration and energy data have been collected and previously published for three Subaru Forester dolly rollover tests, and have been studied in more detail in this writing. This same vehicle model has also been crash tested by the NHTSA.
Technical Paper
2014-04-01
Taewung Kim, Jason Kerrigan, Varun Bollapragada, Jeff Crandall, Ravi Tangirala, Michael Guerrero
Abstract Some rollover test methods, which impose a touchdown condition on a test vehicle, have been developed to study vehicle crashworthiness and occupant protection in rollover crashes. In ground-tripped rollover crashes, speed, steering maneuver, braking, vehicle inertial and geometric properties, topographical and road design characteristics, and soil type can all affect vehicle touchdown conditions. It is presumed that while there may be numerous possible combinations of kinematic metrics (velocity components and orientation) at touchdown, there are also numerous combinations of metrics that are not likely to occur in rollover crashes. To determine a realistic set of touchdown conditions to be used in a vehicle rollover crash test, a lateral deceleration sled-based non-destructive rollover initiation test system (RITS) with a fully programmable deceleration pulse is in development. A full-size SUV vehicle dynamics model was developed and validated with static test data and curb-trip rollover test data.
Technical Paper
2014-04-01
John Patalak, Thomas Gideon, Don Krueger
First required in 1970 in NASCAR® (National Association for Stock Car Auto Racing, Inc) the driver's window safety net or driver's window net has continually evolved and improved. The driver's window net has played an important role in protecting race car drivers from injury. Driver's window nets were originally used to help keep the driver's upper torso, head and arms inside the interior of the race vehicle during crashes. As restraint systems were improved, the role of the driver's window net in stock car racing has transitioned to keeping flailing hands inside the interior of the car while also serving as a shield to protect the driver from intruding debris. This paper describes three separate window net and window net mounting tests and the use of these tests to design an improved window net mounting system. Also shown are test results of previously used window net mounting systems and the improved NASCAR system which has been incorporated into the 2013 NASCAR Sprint Cup, Nationwide Series, and Camping World Truck Series vehicles.
Technical Paper
2014-04-01
Bradley Orme, Robert V. Walsh, Scott Westoby
Abstract Changes in the automotive supply chain over the past several years were brought about by global economic pressures, and forced some materials into tight supply as the industry started its recovery. One such material is polyamide 6,6 fiber (PA 6,6) used for airbags, which was in tight supply in 2008-09. This, with the availability of new low temperature inflators caused some airbag module manufacturers to revisit the use of polyester (PET), which had been used sporadically and in small quantities since the 1970s, although the overwhelming majority of airbags used PA 6,6. Over the last several years PET has been adopted for use in a small number of airbag programs to reduce supply concerns, but this use has come with performance tradeoffs of higher weight, lower tear and seam properties, and other changes. Still, the lower polymer cost of PET has driven a wider evaluation. Polyamide 6,6 and polyester are not equivalent fibers, and differences in thermal capacity, toughness, modulus, and other properties result in different fabric performance.
Technical Paper
2014-04-01
June-Young Song, Kangwook Lee, Byung-Jae Ahn
Abstract Requirements of side curtain airbag have continued to increase. The revised SINCAP, FMVSS-226 ejection mitigation and small overlap of IIHS had added these requirements. To meet all the requirements, high inflator energy and complex cushion shape became necessary. Such situations increased possibility of cushion failure while deploying. Unfortunately, all the design verification tests are usually completed in a relatively latter stage of development and repetitive testing is needed to consider large dispersion of failure probability distribution. Therefore, verification and design improvement by numerical simulation in an early stage are desirable. A simulation method which can verify CAB deployment was developed in this study. The developed method has three distinct features. Firstly, nonlinear fabric materials and membrane finite elements are used to consider fracture of cushion fabric. Secondly, a pre-simulation procedure had been established. An initial state for an accurate analysis can be obtained through the procedure.
Technical Paper
2014-04-01
Vesna Savic, Matthew Pawlicki, Paul Krajewski, Mark Voss, Louis Hector, Keith Snavely
Abstract Global regulations intended to enhance pedestrian protection in a vehicle collision, thereby reducing the severity of pedestrian injuries, are presenting significant challenges to vehicle designers. Vehicle hoods, for example, must absorb a significant amount of energy over a small area while precluding impact with a hard engine compartment component. In this paper, a simple passive approach for pedestrian protection is introduced in which thin metal alloy sheets are bent to follow a C-shaped cross-sectional profile thereby giving them energy absorbing capacity during impact when affixed to the underside of a hood. Materials considered were aluminum (6111-T4, 5182-O) and magnesium (AZ31-O, AZ61-O, ZEK100) alloys. To evaluate the material effect on the head injury criterion (HIC) score without a hood, each C-channel absorber was crushed in a drop tower test using a small dart. Two high speed cameras captured dart image data before and during impact from which HIC scores were computed with stereo digital image correlation (DIC).
Technical Paper
2014-04-01
Hiroyuki Asanuma, Yukou Takahashi, Miwako Ikeda, Toshiyuki Yanaoka
Abstract Japanese accident statistics show that despite the decreasing trend of the overall traffic fatalities, more than 1,000 pedestrians are still killed annually in Japan. One way to develop further understanding of real-world pedestrian accidents is to reconstruct a variety of accident scenarios dynamically using computational models. Some of the past studies done by the authors' group have used a simplified vehicle model to investigate pedestrian lower limb injuries. However, loadings to the upper body also need to be reproduced to predict damage to the full body of a pedestrian. As a step toward this goal, this study aimed to develop a simplified vehicle model capable of reproducing pedestrian full-body kinematics and pelvis and lower limb injury measures. The simplified vehicle model was comprised of four parts: windshield, hood, bumper and lower part of the bumper. Several different models were developed using different combinations of geometric and stiffness representation. A unique model called a multi-layer model developed in this study represented each of the hood and the windshield with a stack of the panel representing the entire area of these components, while applying localized stiffness characteristics and contact definition with a particular pedestrian body region that contacts with the layer represented by the stiffness characteristics.
Technical Paper
2014-04-01
Tushar Baviskar, Jagadish Mahadevaiah, Vijay Shankar Iyer, Mark Neal
Abstract EEVC WG17 Upper Leg impactors have been used to assess the risk of pedestrian upper leg injuries with respect to regulatory and consumer metric rating requirements. The paper compares the femur injury responses between the finite element models of the EEVC WG17 Upper Leg impactor, the FlexPLI and the 50th percentile male GM/UVa pedestrian model on two sample vehicle architectures, for a sedan and a sports utility vehicle. The study shows that the peak femur load and maximum bending moment response are higher in the EEVC WG17 Upper Leg impactor than the FlexPLI and the human body model. Variation studies are carried out to study the influence of impact location on the vehicle, impactor knee height, additional upper body mass and human body model size on the femur injury responses. The FlexPLI femur responses correlate better with those of the human body model and indicate that the impactor has the potential to be an effective surrogate leg form of a pedestrian with appropriate refinement.
Technical Paper
2014-04-01
Dietmar Otte, Birgitt Wiese
This study deals with the risk of injury to the bicyclist's head and the benefits of wearing a bicycle helmet in terms of reduction of injury severity or even injury avoidance. The accident data of 4,245 injured bicyclists as a randomized sample, collected by a scientific research team within the GIDAS project (German In-Depth Accident Study) were analyzed. Given that head injuries result in approximately 40% of bicycle-related crashes, helmet usage provides a sensible first-level approach for improving incidence and severity of head injuries. The effectiveness of the bicycle helmet was examined using descriptive and multivariate analysis for 433 bicyclists with a helmet and 3,812 bicyclists without a helmet. Skull fractures, severe brain injuries and skull base fractures were up to 80% less frequent for bicyclists wearing a helmet. Among individuals 40 years of age and older, a significant increase of severe head injuries occurred if no helmet was used compared to younger persons with helmet.
Technical Paper
2014-04-01
Bingbing Nie, Qing Zhou, Yong Xia, Jisi Tang
Vehicle hood styling has significant influence on headform kinematics in assessment tests of pedestrian impact protection performance. Pedestrian headform kinematics on vehicle front-end models with different hood styling characteristics is analyzed based on finite element modeling. More elevated feature lines near hood boundary and the following continuous hood surface towards fender will result in a different headform motion. It can lead to larger deformation space, more rotation and earlier rebound of the headform impactor, which will benefit the head impact protection performance. In addition, hood geometry characteristics such as hood angle and curvature have effects on structural stiffness. Therefore, inclusion of considerations on pedestrian head protection into the vehicle hood styling design stage may lead to a more effective and efficient engineering design process on headform impact analysis.
Technical Paper
2014-04-01
Timothy P. Austin, Peter A. Chisholm, Roger W. Schreiber, P. Michael Neal
Abstract In the investigation of a collision involving recreational watercraft, analytical methods are generally limited when compared to incidents involving land-based vehicles. As is indicated in previous publications, investigators often rely on time/distance relationships, human factors, the matching of damage to determine vessel positioning at impact, and the recollections of witnesses. When applicable, speed estimates are generally based on the boat engine's revolutions. By considering the engine speed, the drive gear ratio, the propeller pitch, and the likely slip of the propeller, an estimation of the boat's travel speed can be made. In more recent publications, it has been recognized that Event Data Recorder (EDR) technology incorporated into various Electronic Control Units (ECUs) used in automotive applications can be beneficial to collision investigation and reconstruction. These devices record data surrounding diagnostic occurrences, airbag deployments, and, with respect to some heavy vehicles, “last stop” and/or “sudden deceleration” events.
Technical Paper
2014-04-01
Matthew Wood, Nicholas Earnhart, Kelly Kennett
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.
Technical Paper
2014-04-01
Richard R. Ruth, Ada Tsoi
Abstract Kia and Hyundai released publicly available tools in the spring of 2013 to read model year (MY) 2013 vehicle event data recorders (EDRs). By empirical testing, this study determined the tools also read data from some 2010-2012 models as EDRs were phased in by the manufacturer. Fifty-four (54) MY 2010-2012 airbag control module EDRs from the National Highway Traffic Safety Administration's (NHTSA) New Car Assessment Program (NCAP) crash tests were downloaded direct-to-module. The vehicles analyzed were exposed to frontal, side moving deformable barrier (MDB), and side pole tests. The EDR data was compared to the reference instrumentation for speed and Delta V data. Other data elements were also tabulated but are not evaluated for accuracy because they were not fully exercised during the crash tests, the reference instrumentation was not available, or they were outside the scope of this paper.
Technical Paper
2014-04-01
Roger Bortolin, Matthew Arbour, James Hrycay
Abstract Whether large or small, a truck fleet operator has to know the locations of its vehicles in order to best manage its business. On a day to day basis loads need to be delivered or picked up from customers, and other activities such as vehicle maintenance or repairs have to be routinely accommodated. Some fleets use aftermarket electronic systems for keeping track of vehicle locations, driver hours of service and for wirelessly text messaging drivers via cellular or satellite networks. Such aftermarket systems include GPS (Global Positioning System) technology, which in part uses a network of satellites in orbit. This makes it possible for the fleet manager to remotely view the location of a vehicle and view a map of its past route. These systems can obtain data directly from vehicle sensors or from the vehicle network, and therefore report other information such as fuel economy. The fleet manager can receive alerts when high-level brake applications occur, which could be an indication of tailgating or aggressive driving behavior.
Technical Paper
2014-04-01
Richard R. Ruth, Jeremy Daily
Abstract 2013 and 2014 Ford Flex vehicles and airbag control modules with event data recorders (EDRs) were tested to determine the accuracy of speed and other data in the steady state condition, to evaluate time reporting delays under dynamic braking conditions, and to evaluate the accuracy of the stability control system data that the module records. This recorder is from the Autoliv RC6 family and this is the first known external research conducted on post 49CFR Part 563 Ford EDRs. The vehicle was instrumented with a VBox and a CAN data logger to compare external GPS based speeds to CAN data using the same synchronized time base. The vehicle was driven in steady state, hard braking, figure 8 and yaw conditions. The Airbag Control Module (ACM) was mounted onto a moving linear sled. The CAN bus data from driving was replayed as the sled created recordable events and the EDR data was compared to the reference instrumentation. The accuracy and timing of the data on a second stability control CAN bus was verified, and the transfer function between the CAN bus data and the EDR data was mapped, such that EDR data from any set of CAN data can be predicted.
Technical Paper
2014-04-01
Shotaro Odate, Naotoshi Takemura, William Seaman
Abstract Currently, a number of automobile OEMs have been equipped motorized seatbelt systems with volume-production vehicles. Since the current systems are generally initiated by the activation of the automatic collision brakes, or the brake assist systems; the benefit of those systems is limited solely in pre-crash phase. To enhance the effectiveness of the system, we attempted to develop a motorized seatbelt system which enables to control retracing force according to various situations during driving. The present system enables to accomplish both the occupants' comfort and protection performance throughout their driving from when it is buckled to when unbuckled and stored, or during both routine and sport driving, as well as pre-crash phase. Moreover, it was confirmed that lateral occupants' excursion during driving was reduced by up to 50% with the present system.
Technical Paper
2014-04-01
Ada Tsoi, Nicholas Johnson, H. Gabler
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.
Technical Paper
2014-04-01
Greg Webster, Harold Clyde, Barry Hare, Mark Jakstis, Robert Landis, Lance Lewis, Ryan Buetzer
Abstract Four Toyota vehicles were tested in 12 test conditions to compare the Event Data Recorder (EDR) results with data gathered from onboard test instrumentation and the test protocol. The four Toyota vehicles tested were 2013 Model Year (MY) vehicles with EDRs that meet 49 CFR CH. V Part 563. While the previous Toyota EDR versions captured four pre-crash parameters, this generation Toyota EDR (12EDR) includes additional operating parameters and a faster sampling rate before the event trigger, including additional parameters not required by Part 563. The main focus of this research was to analyze the recording of the following driver inputs: accelerator pedal application, brake pedal application, steering wheel angle, and cruise control activation. The EDR-recorded inputs were compared with the values on the HS-CAN. The test results indicate that the 12EDR accurately recorded these driver inputs.
Technical Paper
2014-04-01
Chinmoy Pal, Tomosaburo Okabe, Kulothungan Vimalathithan, Muthukumar Muthanandam, Jeyabharath Manoharan, Satheesh Narayanan
Abstract A comprehensive analysis was performed to evaluate the effect of BMI on different body region injuries for side impact. The accident data for this study was taken from the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS). It was found that the mean BMI values for driver and front passengers increases over the years in the US. To study the effect of BMI, the range was divided into three groups: Thin (BMI<21), Normal (BMI 24-27) and Obese (BMI>30). Other important variables considered for this study were model year (MY1995-99 for old vehicles & MY2000-08 for newer vehicles), impact location (side-front F, side-center P & side-distributed Y) and direction of force (8-10 o'clock for nearside & 2-4 o'clock for far-side). Accident cases involving older occupants above 60 years was omitted in order to minimize the bone strength depreciation effect. Results of the present study indicated that the Model Year has influence on lower extremity injuries. Occurrence of pelvis injury was found to be influenced by BMI and was validated with logistic regression analysis.
Technical Paper
2014-04-01
Michael E. Zabala, Nicholas Yang, Stacy Imler, Ke Zhao, Rose Ray
Abstract Three years of data from the Large Truck Crash Causation Study (LTCCS) were analyzed to identify accidents involving heavy trucks (GVWR >10,000 lbs.). Risk of rollover and ejection was determined as well as belt usage rates. Risk of ejection was also analyzed based on rollover status and belt use. The Abbreviated Injury Scale (AIS) was used as an injury rating system for the involved vehicle occupants. These data were further analyzed to determine injury distribution based on factors such as crash type, ejection, and restraint system use. The maximum AIS score (MAIS) was analyzed and each body region (head, face, spine, thorax, abdomen, upper extremity, and lower extremity) was considered for an AIS score of three or greater (AIS 3+). The majority of heavy truck occupants in this study were belted (71%), only 2.5% of occupants were completely or partially ejected, and 28% experienced a rollover event. In the analyzed data set, none of the belted occupants experienced a complete ejection while 4.4% of unbelted occupants did experience a complete ejection.
Technical Paper
2014-04-01
Ellen L. Lee, Patrick J. Lee, Wilson C. Hayes
Abstract Non-neutral posture prior to impact is one of many factors thought to influence the onset and severity of whiplash associated disorders following low speed, rear impact collisions. The Graphical Articulated Total Body Model (GATB) is one simulation tool that has been used to investigate injury risk in rear impact collisions, though the model has not previously been validated for occupants in non-neutral postures. The main purpose of this study was to evaluate the performance of the GATB model during low speed rear impacts in out-of-position postures, by comparing simulations to previously published volunteer head accelerations. Twelve simulations (four occupants in each of three postures) were performed. Results demonstrated good agreement between the GATB simulations and the volunteer kinematics, with a mean error for peak head acceleration of 3.4 ± 13%. In addition, influence of out-of-position postures on the risk of whiplash injury for different sized occupants was investigated using the Neck Injury Criterion (NIC).
Technical Paper
2014-04-01
William R. Bussone, Michael Prange
Abstract Few studies have investigated pediatric head injury mechanics with subjects below the age of 8 years. This paper presents non-injurious head accelerations during various activities for young children (2 to 7 years old). Eight males and five females aged 2-7 years old were equipped with a head sensor package and head kinematics were measured while performing a series of playground-type activities. The maximum peak resultant accelerations were 29.5 G and 2745 rad/s2. The range of peak accelerations was 2.7 G to 29.5 G. The range of peak angular velocities was 4.2 rad/s to 22.4 rad/s. The range of peak angular accelerations was 174 rad/s2 to 2745 rad/s2. Mean peak resultant values across all participants and activities were 13.8 G (range 2.4 G to 13.8 G), 12.8 rad/s (range 4.0 rad/s to 12.8 rad/s), and 1375 rad/s2 (range 105 rad/s2 to 1375 rad/s2) for linear acceleration, angular velocity, and angular acceleration, respectively. The peak accelerations measured in this study were similar to older children performing similar tasks.
Technical Paper
2014-04-01
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. There was considerable restitution in the impacts with the mattress and the test subjects experienced changes in velocity (ΔVs) of 5.2-11.4 m/s (11.6-25.5 mph).
Technical Paper
2014-04-01
Bethany L. Suderman, Irving S. Scher, Randal P. Ching
Abstract Previous studies have shown that occupant kinematics in lateral impacts are different for near- and far-side occupants. Additionally, injuries to far-side occupants in high-speed lateral impacts have been better documented in the scientific literature; few studies have looked at low-speed far-side occupants. The purpose of this study was to determine the risk of lumbar spine injury for restrained and unrestrained far-side occupants in low- to moderate- speed lateral impacts. The NASS/CDS database was queried for far-side occupants in lateral impacts for different levels of impact severity (categorized by Delta-V): 0 to 8 km/h, 8 to 16 km/h, 16 to 24 km/h and 24 to 32 km/h. To further understand the lumbar spine injuries sustained by occupants in real-world impacts, far-side lateral impact tests with ATDs from the NHTSA Biomechanics Test Database were used to estimate lumbar loads in generic far-side sled tests. From the NASS-CDS data, the risk of an AIS2+ lumbar spine injury was less than 0.2% for lateral impacts with Delta-V's less than 32 km/h.
Technical Paper
2014-04-01
Wade D. Bartlett, Duane Meyers
Abstract The evasive capabilities of motorcycles and riders are often an important consideration when analyzing a motorcycle crash. Specifically, the longitudinal distance or time required for a motorcycle to move laterally some distance can be of critical interest. Previous publications on this topic have not all measured the same thing and have often included limited test data so their results can be difficult to compare or apply. In addition to reviewing some of the literature on the topic, this paper will present the results of a series of tests conducted with four riders on four motorcycles swerving 2 m (6.5 ft) to their left after passing through a gate at speeds of 40 to 88 km/h (25 to 55 mi/h). The most recent testing involved relatively skilled riders who had faster transitions and greater willingness to lean than the “average” rider generally described in the literature. Separating the perception-reaction time from the evaluation of the turn-away maneuver itself simplifies the analysis, though wide individual performance variation still exists.
Technical Paper
2014-04-01
James Funk, Enrique Bonugli, Herbert Guzman, Mark Freund
It has been proposed that low speed collisions in which the damage is isolated to the bumper systems can be reconstructed using data from customized quasistatic testing of the bumper systems of the involved vehicles. In this study, 10 quasistatic bumper tests were conducted on 7 vehicle pairs involved in front-to-rear collisions. The data from the quasistatic bumper tests were used to predict peak bumper force, vehicle accelerations, velocity changes, dynamic combined crush, restitution, and crash pulse time for a given impact velocity. These predictions were compared to the results measured by vehicle accelerometers in 12 dynamic crash tests at impact velocities of 2 - 10 mph. The average differences between the predictions using the quasistatic bumper data and the dynamic crash test accelerometer data were within 5% for bumper force, peak acceleration, and velocity change, indicating that the quasistatic bumper testing method had no systematic bias compared to dynamic crash testing.
Technical Paper
2014-04-01
Joseph Cormier, Mark "Tony" Freund, Enrique Bonugli, Herbert Guzman
Performing a reconstruction of sideswipe interactions is difficult due to the lack of permanent crush sustained by the vehicles involved. Previous studies have provided insight into the forces involved in creating various types of damage for vehicle-to-vehicle interactions during a sideswipe interaction. However, these data may not be applicable to the interaction that occurs when a tractor-trailer steer tire is involved. As demonstrated in previous studies, steer tire interaction produces a unique pattern of markings on the struck vehicle by the protruding lugs (wheel stud) of the steer tire. These studies have demonstrated that the pattern of cycloidal marks created by the wheel lugs can be used to calculate the relative speeds of the vehicles. While this is helpful in understanding the relative motion of the vehicles, it does not provide information regarding the forces applied at the point of contact. The purpose of this study is to assess the structural response of passenger cars during a sideswipe event involving a tractor-trailer steer tire.
Technical Paper
2014-04-01
Nathan A. Rose, Neal Carter
Abstract In a 2012 paper, Brach, Brach, and Louderback (BBL) investigated the uncertainty that arises in calculating the change in velocity and crush energy with the use of the CRASH3 equations (2012-01-0608). They concluded that the uncertainty in these values caused by variations in the stiffness coefficients significantly outweighed the uncertainty caused by variations in the crush measurements. This paper presents a revised analysis of the data that BBL analyzed and further assesses the level of uncertainty that arises in CRASH3 calculations. While the findings of this study do not invalidate BBL's ultimate conclusion, the methodology utilized in this paper incorporated two changes to BBL's methodology. First, in analyzing the crash test data for several vehicles, a systematic error that is sometimes present in the reported crush measurements was accounted for and corrected. This systematic error arises when a vehicle's plastic bumper fascia rebounds more than the underlying structure, creating an air gap and causing the reported crush measurements both to underestimate the actual deformation and to exhibit more scatter than they otherwise would.
Technical Paper
2014-04-01
Toshiyuki Yanaoka, Yasuhiro Dokko
Abstract The high frequency of fatal head injuries of elderly people in traffic accidents is one of the important issues in Japan. One of the causes may be vulnerability of the aged brain. While a human head/brain FE model is a useful tool to investigate head injury mechanism, there has not been a research result using a model considering the structural and qualitative changes of the brain by aging. The objective of this study was to clarify the generational difference of intracranial responses related to traumatic brain injuries (TBI) under impact loading. In this study, the human head/brain FE models in their twenties (20s) and seventies (70s) were used. They were developed by reflecting the age-specific characteristics, such as shape/size and stiffness of brain matter and blood vessels, to the baseline model developed by Global Human Body Models Consortium (GHBMC) LLC. The generational difference of intracranial responses related to TBI, such as cumulative strain damage measure (CSDM), dilatational damage measure (DDM) and elongation of bridging vein (BV), were studied using the models.
Technical Paper
2014-04-01
Raed E. El-jawahri, Tony R. Laituri, Agnes S. Kim, Stephen W. Rouhana, Para V. Weerappuli
In the present study, transfer equations relating the responses of post-mortem human subjects (PMHS) to the mid-sized male Hybrid III test dummy (HIII50) under matched, or nearly-identical, loading conditions were developed via math modeling. Specifically, validated finite element (FE) models of the Ford Human Body Model (FHBM) and the HIII50 were used to generate sets of matched cases (i.e., 256 frontal impact cases involving different impact speeds, severities, and PMHS age). Regression analyses were subsequently performed on the resulting age-dependent FHBM- and HIII50-based responses. This approach was conducted for five different body regions: head, neck, chest, femur, and tibia. All of the resulting regression equations, correlation coefficients, and response ratios (PHMS relative to HIII50) were consistent with the limited available test-based results.
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