Papers by Keyword: Accident Reconstruction

Abstract: In many cases we have to estimate the speed of the vehicles involved in an accident. The aim of this paper is to make a brief presentation of some cases solved on the question of speed and dynamics using different methods and presenting the estimated error obtained. So in the paper it will be taken into account the indication of tachograph diagram with pro and contra arguments assuming that this indication is only informative as far as the tachograph is not specially designed as an accident recorder device. In the paper it will be included the reconstruction of the accident using PC Crash facility in optimization method to reduce the error regarding the trajectory and rest position. For validation of this analysis we will provide also a video surveillance camera film high resolution versus simulation of the accident. Keywords: accident reconstruction, simulation, optimization.

Abstract: In order to simulate and analyze the rolling movement state of motorcycle in collision accidents, the trajectory reconstruction model was studied. The motorcycle’s centroid trajectory model during the process of rolling and the feature point trajectory model during the process of sliding are both constructed. Using the accidents reconstruction and analysis software named PC-Crash and the models constructed in this paper respectively, a real accident case was reconstructed and analyzed. The comparative study between the reconstruction analysis results and the marks remained in the accident scene was conducted. Research showed that, the analysis result reconstructed by the model was consistent with the actual accident scene. This model can be used to reconstruct and analyze the motorcycle’s rolling movement trajectory after collision occurring.

Abstract: Based on the virtual simulation theory, we used three-dimensional modeling software to build modeling road facilities (vehicles, trees, street lights, etc.) for simulating the accident environment, and by using OpenGL technology, achieved reading, displaying and controlling the three-dimensional models. This dynamically realized the three-dimensional animated simulation of vehicle movement. Simultaneously we have calculated in progress the simulation of vehicle crash with the basic theory of automobile collision, vehicle collision model and the law of conservation of energy and momentum. Finally, we constructed a flexible platform for the simulation experiment. The platform is enabling to add and update road, trees, street lamps and house on the simulation environment dynamically, and has ability to analysis the traffic accident. This could give an assistant to the handling traffic accidents.

Abstract: In order to provide a theory algorithm for simulation and reconstruction analysis of automobile two-dimensional eccentric collision accidents, the applicability problems of the traditional dynamics model and trajectory model in this kind of accident were analyzed in theory respectively. Using PC-Crash software and the traditional models, a real accident case was reconstructed and analyzed. The comparative study between the reconstruction analysis results and the vehicles traces remained in the accident scene was conducted. According to the comparative study, reliabilities of the traditional models were verified.

Abstract: The failure of a synchro-self-shifting clutch, a key component in many power units, can lead to the loss of engine power, thereby the failure of the power plant as a whole. This paper introduces the hardware design and software development of SSS clutch data detector based on 16 Bite microcontroller of Motorola, it records the key parameters of SSS Clutch in real time, which can achieve the accident reconstruction and primary diagnoses of the highest possibility of a failure occurring, it is significant importance for research the highest possibility of a failure occurring prediction and fault diagnosis.

Abstract: Braking trace is the important basis to reconstruct the speed of the accident vehicle. There does not exist one-to-one relationship between the barking trace and the vehicle speed. It needs to have a further research on the factors influencing their corresponding relations, otherwise it may appear great errors to reproduce the vehicle speed with the braking trace. This paper analyzes the influence of people, cars, roads, environmental factors on the corresponding relationship between the initial braking velocity and braking traces, explores the use conditions and parameters selection of the reconstructed model in the standard GA/T643-2006, and the experiment is designed to research on the uncertainty of the reconstruction of the model. Besides, it has proposed the experimental reconstruction method.

Abstract: Braking deceleration of passenger-car has great influence on the pedestrian motion process after collision of human-vehicle accident, but it is considered not enough in current accident reconstruction and vehicle-speed analysis. In order to improve the accuracy of accident reconstruction, a computer simulation model of pedestrian-vehicle accidents based on finite element (FE) method and human parameters of Chinese adult human body is established. In this article, based on the FE model, human-vehicle crash is simulated through involving the influence of braking deceleration of passenger-car. For the application of the vehicle-speed analysis, the motion performance of pedestrian after collision were studied and the correlation between the pedestrian throw distance and vehicle impact speed are investigated. The influence of braking deceleration in same impact speed is analyzed. Research results show that the vehicle brake deceleration has a certain influence on the throw distance of pedestrian and it should be taken into account on the accident reconstruction. We can conclude that pedestrian throw distance can be used to estimate the vehicle collision speed accurately when drivers take full braking measure during the crash.

Abstract: Vehicle-pedestrian collision is a major type traffic accident in China, which has been attracted close attention by people because of its high fatality rate. However, it is difficult for traffic management department to reconstruct such kind of accident. In this paper, a methodology for simulation of vehicle-pedestrian accidents based on the multi-body dynamics is presented. A multi-body dummy pedestrian model is established based on PC-CRASH programs, the features that represent the different parts of the pedestrian are defined such as geometry, mass, contact stiffness and coefficients of friction. And more the model is introduced to simulate the collision in a real case of vehicle-pedestrian accident in Hangzhou. Different impact speeds are discussed to predict the different throwing distance of the pedestrian. The relation curves and equations between pedestrian’s throwing distance and vehicle impact speed are established from regression analyses of the simulation data. Finally, the impact speed is estimated with correspond to the exact pedestrian throwing distance.

Abstract: According to the experience of traffic accident investigation over the years, the pointer of some crashed vehicles’ speedometer will stay in one place because of collision spread or heavily vibration, which may indicate the vehicle collision speed. However, the correlation between the residual speed value and actual vehicle collision speed still remains to be examined. For the practical needs of traffic accident reconstruction, this research work is carried out. Based on the principles of traditional speedometers, vehicle impact mechanics and failure mechanism, the damage and failure mode of speedometer in collision are studied. Through the statistics of 15 real traffic accident cases, the features and law about the pointer information of damaged speedometers are obtained initially. As an example, one of these cases is analyzed and calculated to verify the assumption. The availability of the mark information on the indicated place of speedometer after accidents (i.e. the correlation between the speed value of pointers and actual vehicle collision speed) is discussed, which can provide effective means and references for accident reconstruction and vehicle speed identification.

Abstract: In order to analyze the characteristic of cyclist throw distances and head injuries in car to electric-bicycle side impact accidents, this paper presents an approach to reconstruct the car to electric-bicycle side impact accident using PC-Crash. The distribution characteristic of cyclist head impact points with the hood and windshield is analyzed and the relationships between the vehicle impact velocities and the cyclist’s head injuries are described. In addition, based on several factors including road friction coefficient, vehicle load and braking deceleration, we analyzed the relationships between the vehicle impact velocities and the cyclist throw distances. The results show that 50km/h can be regarded approximately as the threshold of impact velocity to cause the cyclist’s head injuries, meanwhile, the cyclist throw distance is less influenced by the road friction coefficient and vehicle load, and the cyclist throw distance might be larger under lower impact velocities and smaller deceleration conditions.