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Viewing 271 to 300 of 15829
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
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.
Technical Paper
2014-04-01
R. Matthew Brach, Raymond M. Brach, Katherine Pongetti
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.
Technical Paper
2014-04-01
Brian Gilbert, Ron Jadischke, Joseph McCarthy
Abstract The analysis and modeling of vehicle crush in accident reconstruction has traditionally been based upon the use of linear crush-based, stiffness coefficients. Engineering Dynamics Corporation (EDC) created the accident reconstruction software Human-Vehicle-Environment (HVE) which contains the collision algorithm called DyMESH (DYnamic MEchanical SHell) which is capable of utilizing a non-linear stiffness coefficient model. The objective of this research was to develop an improved methodology for the calculation of non-linear stiffness coefficients. Stiffness coefficients are used to represent the relationship between the impact force on a vehicle and the resulting vehicle crush. The method explored in the present research was focused on developing vehicle specific, non-linear stiffness coefficients (Pressure Model) based upon frontal crash tests into a fixed, rigid barrier equipped with load cells. The load cell data from the barrier and the accelerometer data from the vehicles were used to establish a force per unit area (pressure) versus vehicle displacement (deflection) relationship.
Technical Paper
2014-04-01
Nathan A. Rose, Neal Carter, David Pentecost
Abstract PC-Crash™, a widely used crash analysis software package, incorporates the capability for modeling non-constant vehicle acceleration, where the acceleration rate varies with speed, weight, engine power, the degree of throttle application, and the roadway slope. The research reported here offers a validation of this capability, demonstrating that PC-Crash can be used to realistically model the build-up of a vehicle's speed under maximal acceleration. In the research reported here, PC-Crash 9.0 was used to model the full-throttle acceleration capabilities of three vehicles with automatic transmissions - a 2006 Ford Crown Victoria Police Interceptor (CVPI), a 2000 Cadillac DeVille DTS, and a 2003 Ford F150. For each vehicle, geometric dimensions, inertial properties, and engine/drivetrain parameters were obtained from a combination of manufacturer specifications, calculations, inspections of exemplar vehicles and full-scale vehicle testing. In each case, the full-throttle acceleration of the vehicles modeled in PC-Crash showed good agreement with the acceleration of the real vehicles in our road tests.
Technical Paper
2014-04-01
Se Jin Park, Seung Nam Min, Murali Subramaniyam, Heeran Lee, Dong Gyun Kim, Cheol Pyo Hong
Abstract Vibration is both a source of discomfort and a possible risk to human health. There have been numerous studies and knowledge exists regarding the vibrational behavior of vehicle seats on adult human occupants. Children are more and more becoming regular passengers in the vehicle. However, very little knowledge available regarding the vibrational behavior of child safety seats for children. Therefore, the objective of this study was to measure the vibrations in three different baby car seats and to compare these to the vibrations at the interface between the driver and the automobile seat. The test was performed on the National road at the average speed of 70 km/h and acceleration levels were recorded for about 350 Sec (5.83 min). One male driver considered as an adult occupant and a dummy having a mass of 9 kg was representing one year old baby. Four accelerometers were used to measure the vibration. All measured accelerations were relative to the vertical direction. Vibration Analysis Toolset (VATS) was used for time domain analysis.
Technical Paper
2014-04-01
Richard Young
A key aim of research into cell phone tasks is to obtain an unbiased estimate of their relative risk (RR) for crashes. This paper re-examines five RR estimates of cell phone conversation in automobiles. The Toronto and Australian studies estimated an RR near 4, but used subjective estimates of driving and crash times. The OnStar, 100-Car, and a recent naturalistic study used objective measures of driving and crash times and estimated an RR near 1, not 4 - a major discrepancy. Analysis of data from GPS trip studies shows that people were in the car only 20% of the time on any given prior day at the same clock time they were in the car on a later day. Hence, the Toronto estimate of driving time during control windows must be reduced from 10 to 2 min. Given a cell phone call rate about 7 times higher when in-car than out-of-car, and correcting for misclassification of some post-crash calls as pre-crash, the final required downward adjustment of the Toronto and Australian RR estimates is about 7 times.
Technical Paper
2014-04-01
Flaura Winston, Catherine McDonald, Venk Kandadai, Zachary Winston, Thomas Seacrist
Abstract Driving simulators offer a safe alternative to on-road driving for the evaluation of performance. In addition, simulated drives allow for controlled manipulations of traffic situations producing a more consistent and objective assessment experience and outcome measure of crash risk. Yet, few simulator protocols have been validated for their ability to assess driving performance under conditions that result in actual collisions. This paper presents results from a new Simulated Driving Assessment (SDA), a 35- to-40-minute simulated assessment delivered on a Real-Time® simulator. The SDA was developed to represent typical scenarios in which teens crash, based on analyses from the National Motor Vehicle Crash Causation Survey (NMVCCS). A new metric, failure to brake, was calculated for the 7 potential rear-end scenarios included in the SDA and examined according two constructs: experience and skill. The study included an inexperienced group (n=21): 16-17 year olds with 90 days or fewer of provisional licensure, and an experienced group (n=17): 25-50 year olds with at least 5 years of PA licensure, at least 100 miles driven per week and no self-reported collisions in the previous 3 years.
Technical Paper
2014-04-01
Richard Young
This study reanalyzes the data from a recent experimental report from the University of Utah investigating the effect on driving performance of auditory-vocal secondary tasks (such as cell phone and passenger conversations, speech-to-text, and a complex artificial cognitive task). The current objective is to estimate the relative risk of crashes associated with such auditory-vocal tasks. Contrary to the Utah study's assumption of an increase in crash risk from the attentional effects of cognitive load, a deeper analysis of the Utah data shows that driver self-regulation provides an effective countermeasure that offsets possible increases in crash risk. For example, drivers self-regulated their following distances to compensate for the slight increases in brake response time while performing auditory-vocal tasks. This new finding is supported by naturalistic driving data showing that cell phone conversation does not increase crash risk above that of normal baseline driving. The Utah data are next compared to those from a larger study that included visual-manual as well as auditory-vocal tasks.
Technical Paper
2014-04-01
Madhav Khadilkar
Abstract The purpose of Federal Motor Vehicle Safety Standard 216 is to reduce fatalities and serious injuries when vehicle roof crushes into occupant compartment during rollover crash. Upgraded roof crush resistance standard (571.216a Standard No. 216a) requires vehicle to achieve maximum applied force of 3.0 times unloaded vehicle weight (UVW) on both driver and passenger sides of the roof. (For vehicles with gross vehicle weight rating ≤ 6,000 lb.) This paper provides an overview of current approach for dual side roof strength Finite Element Analysis (FEA) and its limitations. It also proposes a new approach based on powerful features available in virtual tools. In the current approach, passenger side loading follows driver side loading and requires two separate analyses before arriving at final assessment. In the proposed approach only one analysis suffices as driver and passenger side loadings are combined in a single analysis. This is achieved by using sensors to control loadings, resulting in reduced consumption of CPU time (for computer simulation) and disk space utilization without compromising accuracy of current approach.
Technical Paper
2014-04-01
Payman Khani, Mehrdad S. Sharbaf
Abstract Vehicular Network is an emerging and developing technology to improve traffic management and safety issues, and enable a wide range of value-added services such as collision warning/avoidance. Many applications have been designed to provide safety and comfort for passengers. This technology is a prolific area for attackers who will attempt to challenge the network with their malicious or rational attacks. In this paper we elaborate what a vehicular network is, different kinds of communication in this field, main mechanism and related parts and how vehicular networks work then we introduce some of its applications. After primary familiarity with this system we investigate to different type of attacker, more important security issues, How to secure vehicular networks (security requirements and some tools and methods to achieve secure vehicular networks), difficulties and providing viable security solutions, and at the end briefly explanation of related standards.
Technical Paper
2014-04-01
Fei Han, Weiwen Deng, Sumin Zhang, Bei Ren, Ying Wang, Jie Bai
This paper presents a novel approach of developing a vision-based forward collision warning system (FCW) under a virtual and real-time driving environment. The proposed environment mainly includes a 3D high-fidelity virtual driving environment developed with computer graphics technologies, a virtual camera model and a real-time hardware-in-the-loop (HIL) system with a driver simulator. Some preliminary simulation has been conducted to verify that the proposed virtual environment along with the image generated by a virtual camera model is valid with sufficient fidelity, and the real-time HIL development system with driver in the loop is effective in the early design, test and verification of the FCW and other similar ADAS systems.
Technical Paper
2014-04-01
Kumar B. Kulkarni, Jaisankar Ramalingam, Ravi Thyagarajan
It is of considerable interest to developers of military vehicles, in early phases of the concept design process as well as in Analysis of Alternatives (AoA) phase, to quickly predict occupant injury risk due to under-body blast loading. The most common occupant injuries in these extremely short duration events arise out of the very high vertical acceleration of vehicle due to its close proximity to hot high pressure gases from the blast. In a prior study [16], an extensive parametric study was conducted in a systematic manner so as to create look-up tables or automated software tools that decision-makers can use to quickly estimate the different injury responses for both stroking and non-stroking seat systems in terms of a suitable blast load parameter. The primary objective of this paper is to quantitatively evaluate the accuracy of using such a tool in lieu of building a detailed model for simulation and occupant injury assessment.
Collection
2014-04-01
Active Safety & Advanced Driver Assistance Systems help prevent accidents or mitigate accident severity. Some of these safety systems provide alerts to the driver in critical situations, while others respond to threats by automatically braking and steering the vehicle to avoid crashes. This technical paper collection covers the latest technologies in active safety and driver assistance systems.
Collection
2014-04-01
This technical paper collection focuses on the latest research related to methods and techniques for reconstructing vehicular crashes involving wheeled and tracked vehicles, pedestrians, and roadside features. Emphasis is placed on experimental data and theoretical methods that will enable reconstructionists to identify, interpret and analyze physical evidence from vehicular crashes.
Collection
2014-04-01
This technical paper collection covers papers with an emphasis on, but not limited to, innovative ideas to enhance automotive safety with improved material constitutive modeling, analysis method developments, simulation and pre/post processing tools, optimization techniques, crash code developments, finite element model updating, model validation and verification techniques, dummies and occupants, restraint systems, passive safety as well as lightweight material applications and designs.
Collection
2014-04-01
This technical paper collection focuses on current developments in the fields of vehicle fire science, statistics, risks, assessment and mitigation. Papers addressing vehicle design, live-fire tests and fire investigation issues applicable to traditional, electric and alternatively fueled vehicles are included.
Collection
2014-04-01
This technical paper collection focuses on cybersecurity for cyber-physical vehicle systems. Topics include: design, development and implementation of security-critical cyber-physical vehicle systems, cybersecurity design, development, and implementation strategies, analysis methodologies, process and life-cycle management, comparisons of system safety and cybersecurity, etc. Application areas include: security-critical automotive systems as well as other security-critical ground vehicle and aviation systems.
Technical Paper
2014-04-01
Patrick Galipeau-Belair, Srikanth Ghantae, David Critchley, Sarathy Ramachandra, Moustafa EL-Gindy
Abstract This work describes the design and testing of side underride protection devices (SUPD) for tractor-trailers and straight trucks. Its goal is to reduce the incompatibility between small passenger cars and these large vehicles during side collisions. The purpose of these crash attenuating guards is to minimize occupant injury and passenger compartment intrusion. The methods presented utilize a regulation previously created and published for testing the effectiveness of these devices based on the principles of a force application device already implemented in the Canadian rear underride guard regulation. Topology and multi-objective optimization design processes are outlined using a proposed design road map to create the most feasible SUPD. The test vehicle in question is a 2010 Toyota Yaris which represents the 1100C class of vehicle from the Manual for Assessing Safety Hardware (MASH). Since the tractor-trailers and straight trucks utilize different structural components, separate concepts must be generated to accommodate each individual application.
Technical Paper
2014-04-01
Ellen L. Lee, Patrick J. Lee, Mark S. Erickson, Wilson C. Hayes
Abstract When vehicle-specific stiffness coefficients cannot be acquired, stiffness coefficient values that are representative of the desired vehicle type, class, wheelbase or weight are routinely used for accident reconstructions. Since the original compilation of representative vehicle stiffness data almost 20 years ago, changes in crash testing standards and other safety and technological improvements in vehicular design have affected vehicle stiffness. While generic frontal stiffness data have been recently updated to reflect these vehicular changes, rear and side stiffness data have not. Structural, geometric and inertial data for over 300 passenger cars and light trucks were collected. Among the vehicles targeted were the top-selling cars, SUVs, vans and pickups for model years 1990 to 2012. Results indicated that all vehicle types demonstrated increases in mean stiffness over the time period considered. SUVs were, on average, the stiffest vehicle type in the front, rear and side.
Magazine
2014-04-01
Methodology developed for safer hood design The methodology enables material selection and design optimization of energy absorbers for pedestrian protection based on a simple laboratory test and FE model, eliminating the need for extensive vehicle testing. Developing a winning formula It's been 20 years since the University of Michigan won a Formula SAE championship. Sick of getting smoked in recent years by top teams from Germany and the U.S., MRacing is going "big aero" for a better crack at the 2014 crown.
Technical Paper
2014-04-01
P. Prasad, D. Dalmotas, A. German
Abstract This paper presents the analysis of a series of frontal crash tests conducted by the Insurance Institute of Highway Safety that are commonly referred to as Small Overlap Impacts (SOI). The occurrence and severity of such frontal impacts in the real world were estimated using two different methods. Both methods used the National Automotive Sampling Scheme (NASS), which is a stratified sample of crashes in the US. The first method utilized an algorithm commonly known as Frontal Impact Taxonomy (FIT). The second method was based on comparison of deformation patterns of vehicles involved in frontal crashes in the NASS data files with those produced in tests conducted by the IIHS. FIT analysis of the data indicate that approximately 7.5% of all 11-1 o'clock frontal crashes in NASS are represented by the IIHS SOI test condition and they account for 6.1% of all serious-to-fatal injuries to front seat occupants restrained by seat belts and airbags. Based on the analysis of test and crash front end damage data, it is estimated that the IIHS SOI test mode represents 3% to 8% of all fatal crashes and 4.6 to 9% of all MAIS3+F injury producing frontal crashes.
Technical Paper
2014-04-01
Matthew Wood, Vivek Shekhawat, Tate Kubose, Rajeev Kelkar
Abstract Vehicle stiffness data are often used in crush energy analyses, in conjunction with conservation of momentum calculations, to compute vehicle speeds at impact for accident reconstruction purposes. The vehicle stiffness data are typically obtained from standardized impact tests, such as from the New Car Assessment Program (NCAP) or from Federal Motor Vehicle Safety Standard (FMVSS) tests. Ideally, these data are most applicable when obtained from a sister or clone subjected to an impact similar to the accident. However, when vehicle-specific data are not available, a common alternative is to use crush stiffness values for a generic vehicle population from the published literature. These publications are limited in number and, depending on the user's requirements, may have some inherent limitations. For example, use of the generic values may not readily apply to a recently manufactured subject vehicle involved in a side or rear-end impact. Of the currently published studies providing generic class stiffness data, one publication covers vehicles manufactured in the 1980's and 1990's, while another covers frontal impacts over 3 decades.
Technical Paper
2014-04-01
Greg A. Sullenberger
Abstract A well-established methodology has often been used to calculate a speed-at-impact from the overall distance that a pedestrian is thrown as a result of a vehicle-pedestrian impact. (Searle, SAE #831622 and SAE #930659). The formulae were derived for use on typical road surfaces, such as asphalt, concrete, and grass. Significant testing has been done to validate the formulae on these normal surfaces. The current research was completed to assess if the same formulae are also applicable to lower-friction surfaces, e.g. snow, ice. Test dummies were impacted by automobiles or launched from a ramp in order to simulate the airborne trajectory of a vehicle-pedestrian collision. Speeds were measured with a radar unit and/or the analysis of high speed video. The overall distance traveled by the dummy from impact/launch to final rest was measured. A calculated friction value for the overall throw distance was based upon the known speed and distance and a known or approximated angle of takeoff.
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
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
Anthony Dominic Cornetto, Jeffrey Suway, Ronny Wahba, Fawzi Bayan
Abstract Numerous studies have validated SIMON and DyMESH with respect to vehicle dynamics and crash analysis for accident reconstruction. The impetus for this paper is to develop an accessible methodology for calculating three-dimensional stiffness coefficients for HVE-SIMON and DyMESH. This method uses acceleration-time data (crash pulse) from a vehicle crash test, data that is widely available through the National Highway Traffic Safety Administration (NHTSA). The crash pulse, along with vehicle mass and impact speed, are used to calculate the force acting on the vehicle and the associated vehicle deflection time history. A technique for determining the area-deflection function is created from a computer model of the vehicle, HVE-SIMON, and basic photo-editing software. The calculated force divided by the associated area function (F/A) is plotted versus deflection and a third-order polynomial is then fit to the curve. The coefficients of this third-order polynomial are the A, B, C, and D stiffness coefficients.
Technical Paper
2014-04-01
Ryan Fix, David King, Travis Fricker
Abstract CRASH3 techniques are often used to reconstruct aligned offset vehicle impacts. The goal of this study was to evaluate the accuracy of the CRASH3 technique using a series of aligned staged collision with varying degrees of overlap. Five front-to-rear vehicle impacts using the same vehicle model were staged using 25, 33, 50, 75 and 100% overlap. Impact kinematics were measured using overhead high speed video. The CRASH3 coefficients and methods developed previously (SAE 2010-01-0069) were used to reconstruct the impact speed and speed changes of both vehicles based on the residual crush. Overall, the CRASH3 analysis yielded good results for the 33 to 100% overlap collisions: predicted speed changes were within 29% of the measured speed change and predicted impact speeds were within 16% of the measured impact speed. The CRASH3 analysis yielded poor results for the 25% overlap collision: the predicted speed changes were up to 59% different from the actual speed changes and the predicted impacts speeds were up to 54% different from the actual impact speeds.
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