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Accident Reconstruction, 2013

2013-04-09
The 22 papers in this technical paper collection covers: energy dissipation in high speed frontal collisions; tire friction comparison of three tire types; determining when an object enters the headlight beam pattern of a vehicle; the accuracy of pedestrians in estimating the speed of a moving vehicle; using data from a drivecam event recorder to reconstruct a vehicle-to-vehicle impact and much more.
Collection

Accident Reconstruction, 2011

2011-04-12
The 9 papers in this technical paper collection focus on occupant protection in accident reconstruction. Topics include: particle image velocimetry; heavy truck engine retarders; repeatability and reliability of drag sled testing; pedestrian impact on low friction surface; photogrammetric measurement error associated with lens distortion; passenger vehicle response to low-speed impacts involving a tractor semitrailer; and more.
Software

SAE Accident Reconstruction Technology Collection

1999-06-01
Thank you for your interest in the SAE Accident Reconstruction Technology Collection. This demo gives you an overview of the functionality of the product, illustrating the search interaction and the navigational features. You'll want to try a few searches so you can become familiar with the look and feel of the product and the navigational tools it offers. Please note: this demo does NOT provide you with the content of the product. It contains only one document to show you how you can link from the document summary to the full-text PDF. For information on the content of the product, please see the SAE website. You will be asked to login to the SAE Website before accessing the demo. This will require you to register as a new user if you do not already have an SAE Website account. Click on the following link to access the demo: If you have any questions, please e-mail CustomerService@sae.org or call 1-724-776-4970.
Book

Road Vehicle Dynamics and Problems and Solutions: Set

2010-04-28
This set combines the book Road Vehicle Dynamics with its corresponding workbook companion, Road Vehicle Dynamics: Problems and Solutions. Road Vehicle Dynamics provides a detailed overview of the dynamics of road vehicle systems, giving readers an understanding of how physical laws, human factor considerations, and design choices affect ride, handling, braking, acceleration, and vehicle safety. Chapters cover analysis of dynamic systems, tire dynamics, ride dynamics, vehicle rollover analysis, handling dynamics, braking, acceleration, total vehicle dynamics, and accident reconstruction. The workbook will enable students and professionals from a variety of disciplines to engage in problem-solving exercises based on the material covered in each chapter of that book. It presents systematic rules of analysis that students can follow in a step-by-step manner to understand the efficiencies or shortcomings of various techniques.
Technical Paper

Air Force Safety Practices

1964-01-01
640596
This report outlines the role of the Military Air Transport System in the Air Forces’ effort to conserve the force now in being and its combat capability through the prevention of accidents. It shows the need for conservation and preservation of capabilities to wage a modern technological or conventional war. Discusses the identification and elimination of personnel error as cause factors; and experience gained through accident investigation; reducing the probability of human failure by selection of personnel, clearly defined operational procedures and controlled supervision are also reviewed and discussed.
Technical Paper

Accident Prevention

1964-01-01
640512
Accident prevention is one of the FAA's prime statutory responsibilities. Some of the efforts in carrying out these responsibilities are described in this paper, and the following FAA programs are briefly explained: (1) an air carrier maintenance system of establishing airworthiness alert values so that timely maintenance can be performed, (2) outline of a concentrated program to prevent false fire warnings, (3) development and expansion of positive control in Air Traffic Service, (4) flight checking of airline captains by special trained inspectors, (5) participating in CAB-FAA schooling on accident investigation, and (6) dissemination of safety literature in the general aviation field.
Technical Paper

Results of On-the-Scene Investigations of Accidents

1969-02-01
690808
Of importance for the success of accident prevention campaigns is a definite knowledge of the causes of accidents. Attempts to reconstruct the actual events of accidents through subsequent investigations of the vehicles and at the scenes of the accidents often remain very unsatisfactory, since decisive traces and influences—the key to the solution of the problem—have been altered or are no longer there at all. Through presentation of practical examples and results of first-hand experiences, we will show the advantages of securing and evaluating traces of accidents at the scenes by technical experts for subsequent objective reconstruction of the events. The general method of securing traces, as practiced by the experts of our accident department, will be shown in great detail, as will be the thought processes employed by our experts in connection with suitable individual cases.
Technical Paper

The Abbreviated and the Comprehensive Research Injury Scales

1969-02-01
690810
A widely accepted injury scale is urgently needed by medical engineering automotive accident investigation teams. An informal committee of physicians, engineers and other researchers has developed two scales. The Abbreviated Injury Scale (AIS) combines and details several existing scales including the DeHaven-Cornell scale, the commonly used police scale, and others. Injuries which are usually not fatal are rated with a 1 to 5 scale. Several scaling criteria were combined but with varying weights to establish the AIS rankings. The Comprehensive Research Injury Scale (CRIS) was developed to separate the criteria used in injury scaling. Five separate criteria are used: Energy Dissipation (ED), Threat-To-Life (TL), Permanent Impairment (PI), Treatment Period (TP), and Incidence (IN). The ED scale ranks energy dissipation in injury production, and will be of major value to vehicle designers concerned with human tolerance for injury.
Technical Paper

The Accuracy of Photogrammetry vs. Hands-on Measurement Techniques used in Accident Reconstruction

2010-04-12
2010-01-0065
A study was conducted to assess the relative accuracy of two measurement techniques commonly used for vehicle measurements in damaged-based accident reconstruction. The traditional technique of hands-on measurement was compared with the use of photogrammetry for measurement of targeted damaged vehicles. Three undamaged vehicles were subjected to 4 impacts, resulting in 4 damaged areas (two front, one side and one rear). The study's intent was only to examine the accuracy of each measurement technique. The influence of other confounding independent variables such as selection of measurement location on the vehicle, reference line location, and definitions of what constitutes "damage," etc., were controlled for and minimized by using predefined measurement points on the vehicles and prescribed station lines. The points on each vehicle were measured using both techniques, and compared to baseline reference measurements obtained via a TOPCON GPT-7005i prismless imaging total station.
Technical Paper

EVALUATION OF THE EFFECTIVENESS OF PEDESTRIAN PROTECTION SYSTEMS THROUGH IN-DEPTH ACCIDENT INVESTIGATION, RECONSTRUCTION AND SIMULATION

2009-10-06
2009-36-0398
Around 15% of traffic accident casualties in Europe are pedestrians. To date, most of the studies carried out only provide statistical information on the problem and little study in-depth the countermeasures which might correct it. There are many studies concerning pedestrian protection, which can be grouped into ‘pedestrian modelling’, ‘biomechanical limits for pedestrians’ and ‘statistical analysis for pedestrian accidents’. Despite these studies, there is no predictive analysis of the benefits of pedestrian protection systems based on their intrinsic capabilities applied to a real accident sample. This paper describes a methodology for the evaluation of pedestrian protection systems based on the analysis of a wide sample of urban pedestrian accidents. All of them are analysed in-depth and reconstructed with PC-Crash. The effects of the frontal structure of the vehicles and several active systems, such as BAS and Pedestrian Detection Systems, are evaluated.
Technical Paper

Computer Simulation of Steer-Induced Rollover Events Via SIMON

2011-04-12
2011-01-1122
This study examines through computer simulation the reconstruction of on-road vehicle rollover accidents induced by a driver steering maneuver. The three-dimensional vehicle dynamics software package SIMON is used to model a set of four test vehicles as six degree-of-freedom sprung masses with up to five degrees-of-freedom for each unsprung mass. The performance of the simulator's physics model, in the context of accident reconstruction, is evaluated through correlation with full-scale vehicle rollover tests. Of specific interest to this study was simulation of the trip phase of the vehicle's motion. The correlation parameters include vehicle trajectory, speed, heading angle, yaw rate, roll angle, roll rate and lateral acceleration. SIMON's capacity to accurately model the physics of a test vehicle's suspension and tire kinetics in the pre-trip and trip phases of motion is evaluated by modeling a set of four instrumented full-scale tests of steering-induced rollovers.
Journal Article

Study on Characteristics of Event Data Recorders in Japan; Analysis of J-NCAP and Thirteen Crash Tests

2011-04-12
2011-01-0810
Event Data Recorder (EDR) is a device to record vehicle and occupant information for a brief period of time before, during and after a crash event. EDR is one of the promising devices for accident reconstruction by recording important information e.g. vehicle speed, engine speed, brake switch, throttle and delta-V. However, in order to use EDR for an accident investigation, reliability and accuracy of those EDR data must be examined firstly. The aim of this study is to evaluate the characteristics of EDR and to understand the performance of EDR for the improvement of accident reconstruction with more reliable and accurate information on an accident in Japan. The analysis is based on J-NCAP crash tests from 2006 to 2009 with corresponding EDR datasets. Full-overlap frontal collision test and offset frontal collision test of fourteen car models were analyzed.
Journal Article

A Bayesian Approach to Cross-Validation in Pedestrian Accident Reconstruction

2011-04-12
2011-01-0290
In statistical modeling, cross-validation refers to the practice of fitting a model with part of the available data, and then using predictions of the unused data to test and improve the fitted model. In accident reconstruction, cross-validation is possible when two different measurements can be used to estimate the same accident feature, such as when measured skidmark length and pedestrian throw distance each provide an estimate of impact speed. In this case a Bayesian cross-validation can be carried out by (1) using one measurement and Bayes theorem to compute a posterior distribution for the impact speed, (2) using this posterior distribution to compute a predictive distribution for the second measurement, and then (3) comparing the actual second measurement to this predictive distribution. An actual measurement falling in an extreme tail of the predictive distribution suggests a weakness in the assumptions governing the reconstruction.
Technical Paper

Reconstruction Tests Design to Support the Correlation of Real Injuries with Dummy Readings

2012-10-02
2012-36-0456
From the many sub-tasks of the four study areas of the EC CASPER project, this paper presents the following point: • Child protection improvements as a result of accident reconstructions and development of injury risk curves. The first step in achieving this aim was to collect real world in-depth road accident data involving restrained children, with injuries systematically coded using the AIS (Abbreviated Injury Scale, AAAM 1998). This activity identified the priority body regions to be protected (therefore requiring injury risk curves) and provided cases to be reconstructed in full scale crash tests. In such reconstructions dummy readings were correlated with the occupants' injuries in the real accident to develop injury risk curves (after validation checks for crash severity and dummy kinematics). At the same time, online and field surveys were carried out to identify the safety of children when travelling in cars.
Technical Paper

Using Marine Engine Control Units in the Investigation of Watercraft Collision Incidents - Mercury Verado Outboard Engine

2014-04-01
2014-01-0499
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.
Journal Article

Modeling and Experimental Studies of Crack Propagation in Laminated Glass Sheets

2014-04-01
2014-01-0801
Polyvinyl Butyral (PVB) laminated glass has been widely used in automotive industry as windshield material. Cracks on the PVB laminated glass contain large amount of impact information, which can contribute to accident reconstruction investigation. In this study, the impact-induced in-plane dynamic cracking of the PVB laminated glass is investigated. Firstly, a drop-weight combined with high-speed photography experiment device is set up to investigate the radial cracks propagation on the PVB laminated glass sheet. Both the morphology and the velocity time history curve of the radial cracks are recorded and analyzed to investigate the basic mechanism of the crack propagation process. Afterwards, a three-dimensional laminated plate finite element (FE) model is set up and dynamic cracking process is simulated based on the extended finite element method (XFEM).
Technical Paper

Prediction of Stiffness Coefficients for Frontal Impacts in Passenger Vehicles

2014-04-01
2014-01-0468
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.
Technical Paper

Calculating Non-Linear Frontal Stiffness Coefficients

2014-04-01
2014-01-0474
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.
Technical Paper

Calculating Three Dimensional Stiffness Coefficients for Use in Three Dimensional Simulation Modeling for Accident Reconstruction

2014-04-01
2014-01-0473
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.
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