Explore the forces that arise during a collision

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 space bar 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?