Question

In: Mechanical Engineering

A 4500 lb SUV is traveling at 65 mph when it strikes a staged attenuator designed...

A 4500 lb SUV is traveling at 65 mph when it strikes a staged attenuator designed to produce three different energy dissipation rates. For the first 6 ft, the attenuator produces a force of 20,000 lb on the impacting vehicle. The second stage is 4 ft long and produces a deceleration force of 40,000 lb. “How long does the attenuator’s 3rd stage have to be to safely stop the SUV if its deceleration force is 60,000 lb. Construct the a-s, a-t, and v-t curves for this impact. (Hint: safely stopping the SUV means the vehicle stops before using up the 3rd stage.)

Solutions

Expert Solution

Mass of the SUV = 4500 lb

Initial velocity = 65 mph = 95.30 ft/s

Take first stage data

Take data for 2 stage

Take data for 3 stage

The graph of acceleration and time is given below.

The graph of acceleration and distance is given below.

The graph of velocity and time is given below.


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