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ME 115: Dynamics of Machinery. Manuel Leija Christian Reyes. Professor Granda. Please use this power point to do the grading on. This is a new revised one, the other one was an uncorrected file. Vehicle to Vehicle Collision. Vehicle collisions cause injuries and irreparable damage
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ME 115: Dynamics of Machinery Manuel Leija Christian Reyes
Professor Granda • Please use this power point to do the grading on. This is a new revised one, the other one was an uncorrected file.
Vehicle to Vehicle Collision • Vehicle collisions cause injuries and irreparable damage • In order to analyze the effects of the collisions so as to reduce injuries, three dimensional dynamics and computer simulation programs are necessary
Problem Statement • If a truck runs a stop sign at a constant velocity and then suddenly collides with another car also traveling at a constant velocity, what are the effects on both vehicles • What is transferred through the collision and through which dynamic principles allows this transfer to occur?
Vehicle Information • Truck Data: • Weight = 2900 lb • Velocity = 45 mph (792 in/s) • Coefficient of Restitution =0 (perfectly plastic) • Car Data: • Weight = 2200 lb • Velocity = 25 mph (440 in/s) • Coefficient of Restitution = 0 (perfectly plastic)
Equations: 2D • Truck: 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) • Truck can start anywhere from 990 to 1350 ft. in the y-direction of it’s starting point to ensure a collision • Car: (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) • Car can start anywhere from -33 to 170 ft. in the x-direction of it’s starting point to ensure a collision
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
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)
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, but the transferred energy from the striking vehicle as well. • It’s all about the impulse and momentum principal!!