Traffic Accident Reconstruction Based on Occupant Trajectories and Trace Identification

Author(s):  
Zhang Xiaoyun ◽  
Zhang Dongming ◽  
Yang Xiaobo ◽  
Hou Xinyi

Momentum-based method and multibody method are often used in accident reconstructions. In this paper, a method that combines momentum-based method and multibody method is presented to analyze a real-world accident with occupant ejection. A multibody model is employed as an effective approach to simulate interaction between vehicle and occupants in the postanalysis of a traffic accident. This model can be used to answer questions that which occupant the driver was, when the accident happened, and the vehicle's speed before occupant ejection. Based on the information of the vehicle turn-over location and vehicle speed at the moment of the accident, some unknown parameters of the vehicle before the accident, such as initial speed, acceleration, and vehicle-ground friction coefficient, can be determined. In order to estimate these unknown parameters, a Kriging surrogate model is first constructed for the vehicle movement simulation. The Markov Chain Monte Carlo (MCMC) simulation is then employed to infer the unknown parameters based on the Kriging surrogate model. The results show that a high degree of consistency has been achieved between the computer simulation model and the accident on-scene information. In addition, the injury of occupants in simulation agrees well with conclusions of autopsy report.

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Qiang Chen ◽  
Hong-Guo Xu ◽  
Xiao-Feng Liu ◽  
Zhi-Wei Guan

The analysis of vehicle speeds at the moment of traffic accidents is becoming increasingly important. To solve difficult calculations arising from video analysis when the shooting direction of the camera is the same as the driving direction of the vehicles, an improved plane homography method is proposed. This method is based on detecting the frame rate of and extracting all of the key image frames from a surveillance video. Next, a normalizing approach for the control points is proposed to reduce the ill-conditions of matrix calculations when the perspective image is rectified to an orthographic image. The information in the rectified image is then measured and recorded by extracting the mark point information. Finally, the corresponding curve of time and speed for the examined vehicle is created, which can be used to analyze the average braking deceleration of the accident-causing vehicle. This method can directly determine the speed of a vehicle using videos of a traffic accident without any reference to the dimensions of the vehicle itself. Considering an actual traffic accident as an example, the driving trajectories and velocity curves for two vehicles are obtained using this method. The proposed method can effectively overcome the shortcomings of the commonly used speed recognition methods and it is easy to utilize.


Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 87
Author(s):  
Yongqiang Wang ◽  
Ye Liu ◽  
Xiaoyi Ma

The numerical simulation of the optimal design of gravity dams is computationally expensive. Therefore, a new optimization procedure is presented in this study to reduce the computational cost for determining the optimal shape of a gravity dam. Optimization was performed using a combination of the genetic algorithm (GA) and an updated Kriging surrogate model (UKSM). First, a Kriging surrogate model (KSM) was constructed with a small sample set. Second, the minimizing the predictor strategy was used to add samples in the region of interest to update the KSM in each updating cycle until the optimization process converged. Third, an existing gravity dam was used to demonstrate the effectiveness of the GA–UKSM. The solution obtained with the GA–UKSM was compared with that obtained using the GA–KSM. The results revealed that the GA–UKSM required only 7.53% of the total number of numerical simulations required by the GA–KSM to achieve similar optimization results. Thus, the GA–UKSM can significantly improve the computational efficiency. The method adopted in this study can be used as a reference for the optimization of the design of gravity dams.


2014 ◽  
Vol 505-506 ◽  
pp. 1137-1142
Author(s):  
Li Lin ◽  
Ting Ting Lv

In the process of the traffic accidents confirmation, the identification of vehicle speed when accident occurred is often an important basis for accident confirmation. The paper firstly discusses the models of mechanics and solving method for the vehicle front face, rear end, sides face ,slanted side collision based on the theory of collision mechanics ,it describes how to identify the vehicle rate and collision angle based on the model simplification, the theoretical analysis for dealing with the complicated accidents. The common and formulas are studied based on the classical collision mechanics method. The application range, parameters involved in selection and influence of the formulas are analyzed in detail. Finally the program based on C# is developed according to the identified calculation process for vehicle speed of traffic accident. The vehicle speed is obtained by selecting the collision type, entering the relevant accident pattern, inputting the parameters and clicking the command button .The application can store, modify and display results conveniently , improve efficiency on vehicle speed identification effectively and reduce the processing cycle of traffic accident availably.


2021 ◽  
pp. 43-48
Author(s):  

Improving the system of preventive measures aimed at reducing the severity of the consequences of road accidents is an urgent task. Road deaths are constantly increasing and there is a need for a comprehensive approach to creating safe road conditions. The purpose of this study is to analyze the promising designs of road barriers designed to prevent uncontrolled exit of vehicles from the roadway of the highway and to develop the design of energy-absorbing fencing. Barrier barriers must not only be safe for road users, but must also ensure their safety, as well as preserve the elements after hitting the fence. Analytical studies have shown that in order to reduce mechanical damage to vehicles and reduce the severity of injuries to the driver and passengers, it is necessary to develop a road fence design that allows you to extinguish the impact energy at the moment of contact between the car and the fence. Keywords: fencing, barrier, safety, traffic accident


2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Danyang Wang ◽  
Chunrong Hua ◽  
Dawei Dong ◽  
Biao He ◽  
Zhiwen Lu

Parameters identification of cracked rotors has been gaining importance in recent years, but it is still a great challenge to determine the crack parameters including crack location, depth, and angle for operating rotors. This work proposes a new method to identify crack parameters in a rotor-bearing system based on a Kriging surrogate model and an improved nondominated sorting genetic algorithm-III (NSGA-III). A rotor-bearing system with a breathing crack is established by the finite element method and the superharmonic components are used as index to detect the cracks, the Kriging surrogate model between crack parameters and the superharmonic component amplitudes of the vibration response for rotors are constructed, and an improved NSGA-III is proposed to obtain the optimal crack parameters. Numerical experiments show that the proposed method can identify the crack location, depth, and angle accurately and efficiently for operating rotors.


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