ME 270 Car Crash Test

By Pramod Krishnani Fall 2007

Parameters Used PHYSICAL PARAMETERSM= 1500 Kg, k1= 1 x 104 N/m, b1=500 N-s/m

m= 100 kg, k2= 3 x 105 N/m, b2=8 x 104 N-s/m

For Design Criteria Number 1

• To check the force acting on dummy’s chest when he hits the windshield wearing one seat belt; he travels at 25 and at 55 mph.

Matlab File

Conclusion :

• At 25 Mph and 55Mph ,the dummy hits the windshield and breaks his collar bone.

For Design Criteria Number 2

• To check the force acting on dummy’s chest wearing two seat belt , if he travels at 25 and at 55 mph.

Changing the Parameter Highlighted we make two seat belts

Conclusion :

• At 25 Mph and 55Mph with two seat belts , the dummy hits the windshield and breaks his collar bone.

For Design Criteria Number 3

• To find the critical maximum velocity at which the dummy doesn’t face any kind of injury. Also to find the time required to reach the windshield.

Conclusion :

• The critical velocity at which the dummy doesn’t hit the windshield and doesn’t get any type of injury is 17 MPH . The values for the k1 k2 b1 b2 and the mass of car and dummy is the same as that of given condition.

For Design Criteria Number 4

• If he travels without a seat belt. How long does it take for him to hit the windshield at 25. 40mph, 55 mph. What is the force acting on him on impact at 25 mph, 40 mph, 55 mph

By changing the parameter below we change the system with no seat belt

Conclusion :Time required to hit the windshield for the dummy • For 25 mph is 0.0895 sec• For 40 mph is 0.0559 sec• For 55 mph is 0.0407 sec

The Force Acting on the dummy’s chest is

• For 25 mph is 103.6005 Pounds• For 25 mph is 103.6005Pounds• For 25 mph is 103.6005 Pounds

Final Table Initial

VelocityNo of Belts

Bumper Seat Belts DummyK2

N/mB2

N-s/mK1

N/mB1

N-s/mE5Kg

Q10m

25 1 3 x 105 8 x 104 1 x 104 500 9313 0.816425 2 3 x 105 8 x 104 1 x 104 500 13249 0.744225 0 3 x 105 8 x 104 1 x 104 500 13828 -25 1 50000 9000 10000 2000 6017 0.350125 1 40000 8000 10000 3000 5440 0.259925 1 30000 7000 10000 5000 4809 0.177540 1 3 x 105 8 x 104 1 x 104 500 14906 1.305540 2 3 x 105 8 x 104 1 x 104 500 21166 1.190140 0 3 x 105 8 x 104 1 x 104 500 13828 -55 1 3 x 105 8 x 104 1 x 104 500 20517 1.790155 2 3 x 105 8 x 104 1 x 104 500 29114 1.638655 0 3 x 105 8 x 104 1 x 104 500 13828 -

100 1 30000 7000 10000 5000 19235 0.7087100 1 3000 700 10000 10000 5423 0.3363100 1 30 70 10000 25000 607.46 0.0220

Final Conclusion :• When the dummy travels at a speed of 25 mph and 55 mph with the given

parameters of k1 b1 k2 b2 the dummy breaks the collar bone. He breaks his collar bone if he wears one seat belt as well as for two seat belts. With the given Parameters for k1 b1 k2 b2 the dummy is safe at 17 mph. If the dummy doesn’t wear a seat belt then the force acting on dummy’s chest is shown in the above table in Kg. The dummy at different speeds gives us different values for the Force acting on it and the displacement. After testing with different parameters, I could conclude that the following values for the parameter will give the results listed below the parameters.

K1 = 10000 N/m ; B1 = 25000 N-s / m ; K2 = 30 N/m ; B2 = 70 N-s / m Values at 100 mph

Force Acting on dummy’s chest = 607.46 Kg = 1339.219 lb < 1500 (Permissible)Displacement of Dummy = 0.0220 meters < 1 m (or 100cm ) (Permissible)

Testing at 100 mph with the values of parameters given above makes all the speed below 100 mph safe for the driver ( OR dummy )