Index of Tables vii

List of Figures viii

Introduction & General Topics 1

Introduction 1

Terminology 2

Closing speed 2

Impact Speed Change (V) 2

Barrier Equivalent Velocity (BEV) 3

Coefficient of Restitution 4

Cornering Stiffness And Static Margin 5

Cornering Stiffness 5

Static Margin 7

Sample Application 8

Limitations on the Ability of a Vehicle to Change its Direction of Motion 9

Collinear Central Collisions 16

Collinear Central Collisions (cont.) 17

Error Analysis 17

References 18

Vehicle Control Factors 19

Introduction 19

Wet Pavement 19

Hydroplaning 19

Shoulder Excursions, Pavement Edges 23

References 23

Trajectory Analysis 25

Introduction 25

Linear Motions Without Yawing 25

Spinouts on Flat, Uniform Surfaces 27

Combined Rotation and Translation Subsequent to Collision 31

Yaw Inertia 33

Sample Applications 34

Further Reading 34

Conservation of Momentum 37

Sample Application 1 41

Sample Application 2 - Intersection Collision 44

Sample Application 3 47

References 48

Damage Analysis 49

Introduction 49

History and Analytical Basis 49

Impulse-Energy Relationship 58

Side Impacts: 58

NHTSA Research 61

Forced Intercepts 61

Custom-Fitted Coefficients 64

Abandonment of A, B and G 64

Comparison of Crush Property Definitions 66

Energy Correction Factor and Coefficient of Restitution 67

Energy Correction Factor 67

Coefficient of Restitution 70

2000 Update 70

OFFSET FRONTAL COLLISIONS 75

Refinement in the Simulation of Structural Interactions During Collisions 80

Snag Option 81

References 83

Crush Coefficients 85

Crush Coefficients Derived from Crash Test Data 85

Sample Application to Moving Barrier (Rigid) Test Data: 87

Prasad Coefficients, d0, d1 90

Compatible Crush Definitions for the CRASH and SMAC Computer Programs 91

Sample Calculation 92

References 94

Occupant Trajectory 95

Distance Traveled by an Ejected Vehicle Occupant or Component 95

Simple Ballistic Trajectory 95

Ballistic Trajectory Followed by Sliding 97

Simple Horizontal Launch 98

Horizontal Launch Followed by Sliding 99

LAUNCH Routine. 101

Pole/Tree Collisions 103

Introduction 103

Work-Energy Relationships 103

Conservation of Angular Momentum 105

Relationships for Pure Rotation about Tree/Pole 107

Sample Applications 107

Pole Impact Damage Analysis 110

Sample Application: 111

Crush Properties for m-smac Pole Impacts 117

Effects of Vehicle Pitch 119

References 120

Rollovers 121

Introduction 121

Resistance to Rollover 121

“Static Stability” Factor 121

Tripping Type Rollovers 122

Non-Tripping Type Rollovers 122

Literature Review 122

Minimum Lateral Speed for a Tripping-Type Rollover 124

Speed Required for a Lateral Rollover Beyond 90 126

End-Over-End Rollover 128

References 129

Speed Change at Occupant Positions 130

Background 130

Full-Scale Test Results 131

Test Equivalent Speed Change 132

SMAC Equivalent Speed Change 132

Demonstration of Positional Differences in Speed-Change 133

CG-Transform Procedure 135

References 138

CRASH Damage Analysis 139

Introduction 139

References 140

CRASH Trajectory Solution Procedure 141

Introduction 141

Discussion 145

Tire-to-ground “External” Forces 147

Impact Duration 148

SMAC Computer Program 151

Introduction 151

Current Status of SMAC 152

References 153

HVOSM & 3D Reconstruction Analysis 157

Introduction 157

Research Rationale for Computer Simulation Models 157

HVOSM - Highway Vehicle Object Simulation Model 158

Analytical Approach of the HVOSM 158

The Astro-Spiral Jump 161

Research with HVOSM 162

References 174

CVS/ATB Occupant Simulation Model 177

Introduction 177

Appendix 1 179

Forms of Restitution Behavior 179

Appendix 2 181

Conversion Factors 181

ERRATA 187

Changes made to document since Nov 2000 187

Index 189