momentum6 24 spelling
TRANSCRIPT
The Effect of The Effect of Different “Highway Different “Highway
Barrier” Materials on Barrier” Materials on Force and Time of Force and Time of
Impact in a Impact in a Simulated Car CrashSimulated Car Crash
Danilo, Louis, and BreeDanilo, Louis, and BreePHYS 399PHYS 399Group 2Group 2
BackgroundBackground• 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
• 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
PurposePurpose
HypothesisHypothesis• 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.
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
The Go! Motion is set-up at the top of The Go! Motion is set-up at the top of the ramp w/the Force Sensor mounted the ramp w/the Force Sensor mounted
at the base.at the base.
•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
•The Vernier cart was mounted with an accelerometer to increase the height and weight (7N) of the car
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
Example Data Example Data Impulse=change in momentumImpulse=change in momentum
Final values
Time(s) Force(N) Velocity(m/s) F(∆t)=m(∆v)
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
Initial values
Graph of Force and Time Graph of Force and Time relationrelation
Force during impact and Time of impact vs material
0.00
5.0010.00
15.0020.00
25.00
Control Styrofoam BubbleWrap
Foam Paperball
Fo
rce
(N)
0.00
0.05
0.10
0.15
0.20
Tim
e (s
)
Force Time
Data AnalysisData 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.
ConclusionConclusionImpact Duration vs Impact Force
ControlStyrofoam
Bubblewrap
Foam
Paperball
0.00
5.00
10.00
15.00
20.00
25.00
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16
Duration of impact (s)
Fo
rce o
f im
pact
(N)
Hypothesis supported?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.
LimitationsLimitations• 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
ImprovementsImprovements• 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
ApplicationsApplications• Crumple zones extend the collision,
reducing force on passengers
Air bags inflate on contact absorbing impact Air bags inflate on contact absorbing impact Holes let air escape so collision takes even longer Holes let air escape so collision takes even longer
• Highway barriers that bend in sections to extend collisions
ExtensionExtension• 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)
Image CreditsImage 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