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Introduction
This experiment uses a DrDAQ data logger to explore the forces exerted during a collision.
Equipment required
- Hinged Dummy
- Force Sensor — Honeywell FSG15N1A
- Dynamics Trolley
- Runway
- Lab. Jack
- Ticker–timer and tape
- Power supply for ticker timer
- DrDAQ data logger
- PC running Picoscope oscilloscope software
Construction details
Hinged Dummy
A small piece of doweling is inserted in the body of the dummy, and a force sensor is mounted on a barrier. The final position of the barrier has to be adjusted so that the dowel rod hits the sensor centrally.
Force sensor
Honeywell force sensor FSG15N1A.
Force sensor mounting bracket.
- Pin 1 — to battery
- Pin 2 — to +ve DrDAQ
- Pin 3 — to -ve battery
- Pin 4 — to -ve DrDAQ
Carrying out the experiment
The hinged dummy mounted on a dynamics trolley is allowed to run, out of control, down an inclined track and colide with a buffer. At Collision the dowel rod hits the force sensor and measures force directly and its output voltage is, over the range to approximately 15 N, directly proportional to the force applied.
- Set up the equipment as shown, with the ticker–timer and tape for measuring / timing speed.
- Connect the force sensor to DrDAQ and load the Picoscope software.
- Set the timebase at 10 ms; the X gain to x1; at A select Volts x5; the trigger to single, rising and 5 0 mV; and the display settings to -5%.
- Start the datalogger (click ‘GO’ or press the ‘Spacebar’ with Picoscope) and let the trolley roll down the incline.
- After the collision record the final voltmeter reading or save the file for printing later, repeat for different speeds as necessary,
Further study
- What happens to the forces applied to the dummy if the mass of the trolley is increased?
- What effect does a crumple zone have on the forces exerted on the dummy in a collision?
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