Vehicle Collision Dynamics: Analysis and Reconstruction

Description

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. 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