Vehicle Collision Dynamics: Analysis and Reconstruction

✍ Scribed by Dario Vangi

• Publisher: Butterworth-Heinemann
• Year: 2020
• Tongue: English
• Leaves: 215
• Edition: 1
• Category: Library

✦ Synopsis

Vehicle Collision Dynamics provides a unified framework and timely collection of up-to-date results on front crash, side crash and car to car crashes. The book is ideal as a reference, with an approach that's simple, clear, and easy to comprehend. As the mathematical and software-based modelling and analysis of vehicle crash scenarios have not been systematically investigated, this is an ideal source for further study. Numerous academic and industry studies have analyzed vehicle safety during physical crash scenarios, thus material responses during crashes serve as one of the most important performance indices for mechanical design problems.

In addition to mathematical methodologies, this book provides thorough coverage of computer simulations, software-based modeling, and an analysis of methods capable of providing more flexibility.

✦ Table of Contents

Cover
Dedication
Contents
Preface
Acknowledgment
1 Structural behavior of the vehicle during the impact
1.1 Crashworthiness structures and phenomenological aspects of the impact
1.2 Pulse acceleration curve
1.2.1 Centroid time
1.3 Force–deformation curve
1.4 Distribution of the impact forces over time and space
1.5 Parameters of influence for the force–deformation curves
1.5.1 Vehicle model
1.5.2 Offset
1.5.3 Oblique impact
1.5.4 Underride/override
1.5.5 Impact speed
References
2 Impact impulsive models
2.1 Impact models
2.2 Contact plane, center of impact
2.3 Momentum, impulse, and friction coefficient
2.4 Coefficient of restitution
2.4.1 Closing speed
2.4.2 Mass effect
2.4.3 Structural aspects
2.5 Centered and oblique impacts
2.6 Model with three degrees of freedom
2.6.1 Full and sliding impact
2.6.2 Coefficient of restitution at the center of impact
2.6.3 Directions of pre- and postimpact speeds
2.6.4 Impact against a rigid barrier
2.7 Sensitivity analysis
2.8 Energy
2.8.1 Energy and Kelvin’s theorem
Compression phase
Restitution phase
Kelvin’s theorem
2.8.2 Normal and tangential dissipated energy
2.9 Scalar equations
2.10 Speed change in the center of the impact
2.11 Constant acceleration circle
References
Further reading
3 Models for the structural vehicle behavior
3.1 Lumped mass models
3.1.1 Mass–spring model (Campbell model)
Vehicle-to-barrier impact
Vehicle-to-vehicle impact, effective mass system
Coefficient of restitution in the collision between two vehicles
3.1.2 McHenry model
3.1.3 Kelvin model
Vehicle-to-barrier Kelvin model
Responses of an underdamped systems
Kelvin model parameters identification
Vehicle-to-vehicle Kelvin model
3.2 Pulse models
3.2.1 Halfsine pulse shape
3.2.2 Haversine pulse shape
3.2.3 Triangular pulse shape
3.2.4 Macmillan model
3.2.5 Example
3.3 Direct integration of the curves F(x)
3.4 Reduced order lumped mass model
3.4.1 Model description
Contact identification
Plane of impact and impulse direction
Directly connected nodes identification
Calculation of impact forces
Calculation of final kinematic parameters
References
4 Energy loss
4.1 The classical approach to estimate the energy loss
4.2 Correction for oblique impacts
4.2.1 Measurement of deformation depths
4.3 Determination of A and B stiffness coefficients from the residual crush
4.3.1 Crash against fix rigid barrier
4.3.2 Crash against a mobile rigid barrier
4.3.3 Oblique crash against fix rigid barrier
4.4 Determination of A and B stiffness coefficients from dynamic deformation
4.5 Energy equivalent speed
4.6 Triangle method
4.7 Triangle method with dynamic deformations
References
5 Crash analysis and reconstruction
5.1 Crash analysis
5.1.1 Impact configuration
5.1.2 Center of impact and contact plan
5.1.3 Principal direction of forces
5.1.4 Postimpact phase analysis
5.1.5 Energy loss evaluation
5.1.6 Preimpact velocity calculation
5.1.7 Results check
Check 1—momentum conservation
Check 2—compatibility between pre- and postimpact velocities
Check 3—energy conservation
5.2 Example
5.2.1 Impact configuration and point of impact
5.2.2 Center of impact an contact plane
5.2.3 Principal direction of forces evaluation
5.2.4 Postimpact analysis
5.2.5 Energy loss calculation
Measurement of the extent of deformations
Energy equivalent speed evaluation by case comparison
5.2.6 Preimpact velocity calculation using the method based on momentum calculation
Results check
5.2.7 Preimpact speed calculation based on deformations measurements
Results check
5.2.8 Velocities from the video analysis
References
Index