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Technical Paper

Real-world car accident reconstruction methods for crash avoidance system research

The paper describes the multidisciplinary systemic approach leading to the comprehensive methodology used in accident reconstruction in order to determine the best scenario, and to assess initial car speeds, paths and events in the different phases of the accident. ...Upon this first step, a more accurate accident simulation can be calculated with a reconstruction software. Results and examples of applications are given in the most common pre-crash situations (curves, straight roads and intersections). ...The paper describes the multidisciplinary systemic approach leading to the comprehensive methodology used in accident reconstruction in order to determine the best scenario, and to assess initial car speeds, paths and events in the different phases of the accident. This has already been carried out for about 400 car crashes with car occupant injuries (including 6% fatal and 10% severely injured).
Technical Paper

Application of Monte Carlo Analysis to Life Cycle Assessment

This paper demonstrates the use of Monte Carlo Analysis to track and measure the propagation of uncertainty in LCA studies. The Monte Carlo technique basically consists of running repeated assessments using random input values chosen from a specified probable range. ...While measuring the overall LCA uncertainty, the Monte Carlo technique also measures the uncertainty contribution of each unit process within the system being considered. ...The Monte Carlo technique basically consists of running repeated assessments using random input values chosen from a specified probable range.
Technical Paper

Friction Applications in Accident Reconstruction

The determination of appropriate friction coefficient values is an important aspect of accident reconstruction. Tire-roadway friction values are highly dependent on a variety of physical factors. ...This paper presents a technical review of basic concepts and principles of friction as they apply to accident reconstruction and automobile safety. A brief review of test measurement methods is also presented, together with simple methods of friction measurement to obtain more precise values in many situations. ...Factors such as tire design, side force limitations, road surface wetness, vehicle speed, and load shifting require understanding if useful reconstruction calculations are to be made. Tabulated experimental friction coefficient data are available, and may be improved upon in many situations by simple testing procedures.
Technical Paper

Hydroplaning and Accident Reconstruction

Also, a set of rules is suggested that may be used during accident reconstruction to determine if a vehicle has in fact hydroplaned and the potential source.
Technical Paper

Sensitivity of Accident Reconstruction Calculations

A number of simplistic formulae, based on particle dynamics, energy, and momentum methods are routinely employed by accident reconstructionists to calculate vehicle speeds immediately prior to impact. It is almost always the case that scene evidence and other information regarding important variables involved in such equations must either be estimated or can be measured only in an approximate way. ...Example problems illustrate the difficulties faced by accident reconstructionists as they grapple with incomplete and/or estimated values for important variables, and with the inherent sensitivity of some of the calculations to seemingly small variations in variable magnitudes.
Journal Article

Automatic Transmission Gear Ratio Optimization and Monte Carlo Simulation of Fuel Consumption with Parasitic Loss Uncertainty

An enterprise approach for vehicle fleet balancing of fuel consumption objectives based upon selection of automatic transmission gearing strategy is presented. Monte Carlo simulations for the influence of parasitic loss uncertainty for the automatic transmissions selected from the generalized DOE were conducted to determine the range of fuel consumption that might be realized in production. ...Automatic transmission gearing parameter selection was unaffected by the variation introduced by the Monte Carlo simulations, but did show fuel consumption performance to vary upwards of 9 g CO2/km depending on applications and to have a direct impact on powertrain operating parameters.
Technical Paper

Particulate Matter Formation Dynamics as Investigated by Ultra-Accelerated Quantum Chemical Molecular Dynamics Coupled with Canonical Monte Carlo Method

Suppression or reduction of soot emissions is an important goal in the development of automotive engines for environmental and human health purposes. A better understanding at the molecular level of the formation process of soot particles resulting from collision and aggregation of smaller particles made of Polycyclic Aromatic Hydrocarbon (PAH) is needed. In addition to experiments, computational methods are efficient and valuable tools for this purpose. As a first step in our detailed computational chemistry study, we applied Ultra-Accelerated Molecular Dynamics (UAQCMD) and Canonical Monte-Carlo (CMC) methods to investigate the nucleation process. The UA-QCMD can calculate chemical reaction dynamics 107 times faster than conventional first principle molecular dynamics methods, while CMC can calculate equilibrium properties at various temperatures, pressures, and chemical compositions.
Technical Paper

Tire-Road Friction in Winter Conditions for Accident Reconstruction

The paper presents original research and summarizes the published literature regarding tests of tire-road friction in winter conditions. The original research investigated the effect of temperature variation on tire-road friction on a variety of winter driving surfaces, including an investigation of the variation of friction coefficient with the dispersion rate of applied sand. Tests were conducted on surfaces including bare asphalt, black ice, ice and snow, ice and snow with a variety of sand overlays, ice and snow with a layer of fresh snow, and glare ice at temperatures ranging from -42°C to -4°C (-44°F to 25°F). The published literature relating to tests of friction in winter driving conditions was surveyed, and data from the original research and the previous publications is presented in a uniform fashion.
Journal Article

Application of Air Brake Performance Relationships in Accident Reconstruction and Their Correlation to Real Vehicle Performance

This research paper builds onto the wealth of technical information that has been published in the past by engineers such as Flick, Radlinski, and Heusser. For this paper, the pushrod force versus chamber pressure data published by Heusser are supplemented with data taken from brake chamber types not reported on by Heusser in 1991. The utility of Heusser's braking force relationships is explored and discussed. Finally, a straightforward and robust method for calculating truck braking performance, based on the brake stroke measurements and published heavy truck braking test results, is introduced and compared to full-scale vehicle test data.
Technical Paper

A Method for Accident Reconstruction and Neighborhood Analysis Using an Autonomous Situational Model of Flight and Flight Recorder Data

Available flight recorder data are used to tune the model and reconstruct the accident. Then the model is used for in-depth examination of the accident’s “neighborhood” in autonomous “what-if” simulation experiments under actual and hypothetical conditions. ...Flight accidents with modern aircraft are often a result of complex dynamics of the “pilot (automaton1) - vehicle - operational environment” system. ...An affordable, practically tested technique is proposed to complement current methods of flight accident analysis. A generic situational model of the system behavior and a computer are employed as a virtual test article.
Technical Paper

Computer Program for Reconstruction of Highway Accidents

In one of the presented applications to a staged collision, the initial conditions were kept unknown until completion of the reconstruction process. Results of sample applications to actual highway accidents are included. ...The Simulation Model of Automobile Collisions (SMAC) computer program has been developed for the purpose of achieving uniformity in the use of analytical techniques for interpretation of physical evidence in investigations of highway accidents. The comprehensive output information of the SMAC program (kinematics, tire tracks, and vehicle damage) permits extensive, detailed comparisons with physical evidence in the iterative runs used to achieve a “best fit,” and the predicted vehicle responses provide a basis for relatively refined categorization of occupant exposures. ...Computer graphics displays of reconstructed accidents, including rest positions, tracks, and damage, are presented.
Technical Paper

Accident Avoidance-Crosswind Sensitivity of Some Streamlined Cars

This paper is based on a detailed analysis of real-life situations and is intended to highlight some of the problems that can occur with modern lightweight cars when their aerodynamic shape approaches that of an aerofoil. The problem of disappointing straight line stability when travelling at speed may be more pronounced in the United Kingdom than in Central Europe where one of the cars so flawed was conceived and developed. The topography, significantly higher crosswind speeds, the alignment of the main trunk roads relative to the prevailing winds of high speed, and the proneness for such winds to have extraordinary gust levels are cited as an explanation for the difficulties experienced by motorists when the low drag, front-engine, rear-wheel-drive car was launched in 1982/83. Progress has been made to minimise the handling problems under high speed and crosswind situations, but there is little chance of achieving better driver skill.
Technical Paper

Abdominal Twin Pressure Sensors for the Assessment of Abdominal Injuries in Q Dummies: In-Dummy Evaluation and Performance in Accident Reconstructions

The APTS ability to detect abdominal loading in sled tests was also confirmed, with peak pressures typically below 1 bar when the belt loaded only the pelvis and the thorax (appropriate restraint) and values above that level when the abdomen was loaded directly (inappropriate restraint). Then, accident reconstructions performed as part of CASPER and previous EC funded projects were reanalyzed.
Technical Paper

Analysis under Vehicle-Pedalcyclist Risk Scenario Based on Comparison between Real Accident and Naturalistic Driving Data

This paper constructs the Accident Crash Scenarios(ACSs) classification system based on the traffic accident data collected by the traffic management department in a Chinses city from 2013 to 2015. ...Driving Reliability and Error Analysis Method(DREAM) was used to analyze which induced factors are more likely to lead to accidents under the scenarios involved Car-Pedalcyclist in intersection. The result shows Too late actions and Too high speed are two induced factors of top two critical levels, Misjudgment and Expectance of certain behaviors are responsible for these two induced factors.
Technical Paper

Application of Signal Reconstruction to On-Road Emissions Testing

Data was taken from these analyzers and passed, off-line, through the reconstruction filter. In addition, part of the Federal Urban Driving Schedule was simulated on the chassis dynamometer and emissions data collected from the test vehicle.
Technical Paper

The Reconstruction of Periodic Pressure Fields from Point Measurements

A new method for processing data from time-accurate point measurements has been developed in order to investigate periodic elements of unsteady flow fields. The technique synchronizes the phase of measurements taken at different locations using a reference signal and collapses the spectral peak of interest onto a single frequency. The technique has been applied to data gathered using a time-accurate 5-hole probe behind a two dimensional body exhibiting vortex shedding. It has been possible to generate a sequence of instantaneous pressure and velocity fields which show the shedding of vorticity and total pressure loss to form a vortex street.