Project challenge: Analyse vibration of absorption tubes used to stop falling objects?One of the universities in Johannesburg (South Africa) needed detailed vibration analysis of absorption tubes used to stop falling object such as elevators in a runaway situation.
The measurement had to take place on the falling object, in this case a 6m scale model of an elevator, and the velocity of the falling object needed to be determined as it made impact with the absorption tubes. |
WHAT IS THE VELOCITY OF A FALLING ELEVATOR?
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JAD solution
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It was decided that a high speed data logger would be used to measure the deceleration curve and transients. JAD Systems also decided not to put the measurement hardware onto the falling object but rather to use a extension pulley system to feed the cable loom down the shaft to the test platform.
JAD created a custom optical fibre-based precision speed trap that measured the velocity of the falling object over the last 100mm. This was done by gating a high frequency source in a counter input on a micro. The speed trap also had a digital output to trigger the National Instrument SCXI IEPE measurement device to start logging to file. Data was logged to National Instrument signal express and reports were produced in MSExcel. The solution was found to be highly repeatable and accurate. |
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