1. ME 115: Dynamics of Materials
Manuel Leija
Christian Reyes

2. to Vehicle Vehicle Collision
To further understand collisions and the effects in different cases, three dimensional kinematic and dynamic force analysis is essential.

3. Three
Car
Collision: 2D
Assume two cars colliding perpendicular to each other, find the resulting forces and momentum after collision.
How would it affect another on-coming vehicle if hit?

4. Three Car Collision: 2D
Solving the previous problems would seem easy for anyone, but in reality, there are a lot more factors to be considered.

5. Solidworks Model of Truck

6. Solidworks Model of Car

7. Vehicle Data
Working Model: Truck=2900 lb and mph, Car1=2200 lb and 25 mph, Car2=2200 lb and 25 mph, Coefficient of Restitution =1
Nastran (unrealistic): Same as Working Model
Nastran (realistic): Same as Working Model but with a coefficient of friction=.5 between the road and the tires

8. Working Model Simulation

9. Working Model: 2D

14. Equations: 2D Car A: x = xo + v*t
Solved for time to collide with Truck using xo = 0 and x = 50 ft, and constant velocity vA = 25 mph (440 in/s)
Car B: (x – xo)B = vB*tA = (vB/vA)(x – xo)A
Solved distance that would cause collision using Car A as reference with xoB = 0 at vB = 45 mph (792 in/s)

15. Other General Equations: 2D
Kinematics of Rigid Bodies
Position Analysis, Translation, Rotation
Kinetics of Rigid Bodies
General Plane Motion
Momentum and Impulse
Conservation of Energy

16. Nastran 4D Three dimensional kinematic and dynamic analysis made easy.
Similar scenario with only two vehicles.
Two different situations:
Unrealistic (frictionless surface)
Realistic (with friction)

17. Unrealistic
(No Friction)

18. Linear Momentum Data

19. Right Before Impact

20. Bam!!

21. Realistic (with Friction)

22. Realistic (with Friction)

24. Before Impact
(with Friction)

25. Immediately After Impact

26. Basic Drop Test

27. Maximum Contact Force (at h=2ft)

28. Learning Experience
How to use modeling programs to simulate real life situations.
Use analytical techniques from class for solving problems.
Despite what most car manufacturers say, truth be told, do not roll your car!!!! 
It’s not just the car itself that damages the vehicle, it’s all translated energy also.
It’s all about impulse and momentum!!