Automobile Accident Reconstruction by Dynamic Simulation

219 Pages·2007·2.54 MB·English

by  Reed, Walter S.

TECHNICAL REPORT STANDARD TITLE PAGE
1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.
4. Title and Subtitl. S. Report Dole
May 1983
AUTOMOBILE ACCIDENT RECONSTRUCTION
BY DYNAMIC SIMUIATION 6. Performing Orgonization Code
7. Authorl sl B. Performing Organization Report No.
Wa1 ter S. Reed Research Report 302-1F
9. Performing Organization Name and Addre .. 10. Work Unit No.
Center for Transportation Research
The University of Texas at Austin 11. Controct or Grant No.
Research Study 3-18-80-302
Austin, Texas 78712-1075
13. T I'pe of Report ond Period Covered
~~~--------~--~~--------------------------~
12. Sponsoring Agencl' Name ond Addre ..
Texas State Department of Highways and Public Final
Transportation; Transportation Planning Division
P. O. Box 5051 de
Austin, Texas 78763
15. Supplementary Notes
Study conducted in cooperation with the Texas State Department of Highways and
Public Transportation
16. Abstract
The overall motivation for this study is to improve the safety of automobile
travel through a better understanding of the predominant characteristics which
lead to an accident and influence injury severity. Quantification of conditions of
accidents and vehicle and occupant behavior have currently led to many improvements
in the design of vehicles and roadways, as well as aiding our legal system in
administrating justice. Simulation of vehicle colliSions has played an important
role in this progress. Yet, substantial potential for further improvement exists.
The focus of this report pertains to the approach being taken in the of
deve1op~ent
new dynamic computer simulation techniques by a research team at The University of
Texas at Austin.
The work presented herein represents only the beginning of a very extensive
program of The progress to date has been quite good and represents a
rese'~rch.
significant step in accomplishing our goals.
17. Key Words lB. Distribution Statement
automobile accident, reconstruction, No restrictions. This document is
simulation, safety, computer, available to the public through the
modularized algorithms, impact, National Technical Information Service,
trajectory Springfield, Virginia 22161.
19. Security Clalli!. Cof this report) 20. Secu,ity CI ...I f. Cof this page) 21. No. of Page. 22. Price
Unclassified Unclassified 222
Form DOT F 1700.7 18.U)
AUTOMOBILE ACCIDENT RECONSTRUCTION
BY DYNAMIC SIMULATION
by
Walter S. Reed
Research Report Number 302-lF
Automobile Accident Reconstruction
by Dynamic Simulation
Research Project 3-18-80-302
conducted for
Texas
State Department of Highways and Public Transportation
in cooperation with the
U. S. Department of Transportation
Federal Highway Administration
by the
CENTER FOR TRANSPORTATION RESEARCH
BUREAU OF ENGINEERING RESEARCH
THE UNIVERSITY OF TEXAS AT AUSTIN
May 1983
The contents of this report reflect the views of the
authors, who are responsible for the facts and the
accuracy of the data presented herein. The contents
do not necessarily reflect the official views or
policies of the Federal Highway Administration. This
report does not constitute a standard, specification,
or regulation.
There was no invention or discovery conceived or
first actually reduced to practice in the course of
or under this contract, including any art, method,
process, machine, manufacture, design or composition
of matter, or any new and useful improvement thereof,
or any variety of plant which is or may be patentable
under the patent laws of the United States of America
or any foreign country.
ii
ACKNOWLEDGEMENTS
I would like to first express my sincere appre
ciation to all those members of the Governor's Office of
Traffic Safety and later the Office of Traffic Safety,
Texas Department of Highways and Public Transportation
who interacted with me and supported this work. I am
deeply indebted to these people who were kind enough to
support my work for many years and provide a basis for
my professional development in this field. Without their
help, my work in this area would not have been possible
and the current support for my work would not have been
forthcoming.
I would also like to thank Dr. Craig Smith
whose contributions to this project were substantial.
His leadership in developing the MASS concept laid the
foundation for much of what the current' system has
evolved into. I also would like to thank all of the
dedicated students who have put the pieces of this sys
tem together and made our concept a reality.
iii

SUMMARY
The overall motivation for this study is to improve the safety of
automobile travel through a better understanding of the predominant charac
teristics which lead to an accident and influence injury severity. Quantifi
cation of conditions of accidents and vehicle occupant behavior have currently
lead to many improvements in the design of vehicles and roadways, as well as
aiding our legal system in administrating justice. Simulation of vehicle
collisions has played an role in this progress. Yet, substantial
imp~rtant
potential for further improvement exists. The focus of this report pertains
to the approach being taken in the development of new dynamic computer simula
tion techniques by a research team at The University of Texas at Austin.
The work presented herein represents only the beginning of a very
extensive program of research. The progress to date has been good and
q~ite
represents a significant step in accomplishing our goals.
v

TABLE OF CONTENTS
Acknowledgement iii
Chapter I - Introduction 1
Chapter II - Vehicle Collision Reconstruction 13
Impact phase: Principle of Impulse and 14
Momentum
Impact phase: Conservation of Mechanical 18
Energy
Trajectory Phase: Conservation of Mechanical 20
Energy
Simulation Techniques 21
Computer Simulation of Vehicle Collisions: 28
A Survey
r10dular Accident Simulation System 31
Chapter III - Trajectory Analysis Algorithm 35
Derivation of Vehicle Equations of ~otion 35
Tire Model 42
Speed Dependency 43
Tire Forces 44
Wheel Slip Angle 47
Tire Force Direction 48
Friction Circle Concept 49
Tire Lateral Force Model 53
Chapter IV - Impact Phase Analysis 57
General Impact Equations 58
Linear Momentum Impact Equations 58
vii
viii
Angular Momentum Impact Equations 61
Impact Analysis Equation Systems 63
Classification of Linear Momentum Eauation 65
Variables
Classification of Angular Momentum Equation 68
Variables
Solution of Impact Analysis Equation Systems 70
Chapter V - A Computer Hardware/Software System 75
MASS Operating System 77
Graphic Input Device 77
Control and Execution of Analysis Modules 84
Graphic Output Device 85
output File Management 87
Reconstruction Example 91
Description of Accident 91
Collection of the Data 93
Scale Drawing 93
Vehicle and Zone Properties 95
Input of Data to MASS 101
Display of Post-Crash Output 110
Impact Analysis 113
Pre-Crash Analysis 115
Miscellaneous Information 116
Chapter VI - Measurement of Road/Tire Friction 119
Characteristics
General Considerations 119
The Coefficient of Friction U7
ix
Measurement Techniques 134
Accelerometer 146
ltlicro-Computer 152
Computer Mode Operations 159
Calibration 160
Execution 163
Tape Dump 165
Display G'S 166
Fifth Wheel 166
System Testing and Data Evaluation 167
Testing Procedure 169
Test Results 171
Chapter VII - Summar and Current Work 203
References 205