399- Group PowerPoint

1. The Effect of
Different “Highway
Barrier” Materials on
Force and Time of
Impact in a
Simulated Car Crash
Danilo, Louis, and Bree
PHYS 399
Group 2

2. Background
• Demonstrates the first law of momentum
• In a collision, an object experiences a
force for a specific amount of time which
results in a change in momentum
• Tested different materials to simulate
which one will be effective to save lives
during collision
– soft sponge, foam, paper and plastic bubbles

3. Purpose
• By increasing the time of impact, we
reduce the immediate force of the
impact for the occupants of the car
while maintaining a consistent
momentum
• Therefore we want to find the most
effective material to meet this need

4. Hypothesis
• Research Question: Which “highway
barrier” material will best increase the
time of impact in a simulated car crash?
• If various “highway barrier” materials
are tested in a simulated car crash,
then a hollow inelastic material will
increase the time of impact the most
because it is collapsible unlike solid
materials and is inelastic unlike
plastic/rubber materials.

5. Lab Set-Up
•The ramp
should be set
at some
constant angle
(we used about
5°) and a
constant start
distance of 50
cm
•This will
provide a
constant
velocity

6. The Go! Motion is set-up at the top of
the ramp w/the Force Sensor mounted
at the base.

7. •The Vernier cart was
mounted with an
accelerometer to
increase the height and
weight (7N) of the car
•Be sure to use the
standard channel ports for
the LabQuest Interface
•We used a single device
taking 100 samples/s to do
both readings to ensure that
both sensors would be time
synced

8. Experimental Method:
•Mount test materials to the
force sensor and re-calculate
the 50 cm distance to ensure
constant velocity before
impact
Test
materials
used

9. Example Data Impulse=change in momentum
Time(s) Force(N) Velocity(m/s) F(∆t)=m(∆v)
Initial values
delta(∆)=final-initial value
We must average the Force over
the duration of impact.
Using above formula we see that
6.06N(0.11s)=0.714kg(0.95m/s)
0.6667 N*s=0.6783 kg*m/s
0.67 N*s=0.68 kg*m/s
Seems to indicate consistent data
across two sensors
Final values

10. Graph of Force and Time
relation
Force during impact and Time of impact vs material
Force Time
25.00 0.20
20.00 0.15
Force (N)
Time (s)
15.00
0.10
10.00
5.00 0.05
0.00 0.00
Control Styrofoam Bubble Foam Paperball
Wrap

11. Data Analysis
• The data we collected shows that the
Origami Ball was most effective in
increasing the time of impact,
thereby reducing the force of impact.
• The control and Styrofoam material
was least effective in increasing the
time of impact.

12. Conclusion
Impact Duration vs Impact Force
25.00
Control
20.00
Styrofoam
Force of impact (N)
Bubblewrap
15.00
10.00
Foam
5.00
Paperball
0.00
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16
Duration of impact (s)

13. Hypothesis supported?
• Yes, our hypothesis was supported
by the data that the hollow,
collapsible, inelastic material was
most effective in increasing the time
of impact and reducing the
immediate force of impact.

14. Limitations
• Due to digital sensitivity of the
sensors, events may occur between
readings
• Sensitivity of sensors to sound, may
cause discrepancy of data
• Human error for distance and start
time
• Price of materials and the
equipments

15. Improvements
• Trigger device to prompt readings
from sensors
• Consistency in size of test materials
• Limitation on mass of test material
• Use of the accelerometer instead of
Go! Motion sensor

16. Applications
• Crumple zones extend the collision,
reducing force on passengers

17. Air bags inflate on contact absorbing impact
Holes let air escape so collision takes even longer

18. • Highway barriers that bend in
sections to extend collisions

19. Extension
• Testing the ideal thickness of one
test material to increase the time of
impact
• Testing airbag material rather than
highway barrier
• Testing crumple zone of the car
(having the material attached in
front of the car)

20. Image Credits
• Slide 16 - http://image.motortrend.com/f/auto-news/volvo-wants-to-
make-its-cars-injury-proof-by-2020/9805935+w562+cr1+re0+ar1/volvo-
crash-test.jpg
• Slide 17 - http://media.canada.com/b17a5268-e809-4db2-
a84b-06fc4c00d03e/m1x00181_crashtestdummy.jpg
• Slide 18 -
http://www.eplcompositesolutions.co.uk/composite/crashBarriers.asp