Experiment: three-point bending – PASCO ME-9891 Flexible I-beam User Manual
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F l e x i b l e I - b e a m
E x p e r i m e n t : T h r e e - p o i n t B e n d i n g
6
Experiment: Three-point Bending
Equipment
See Equipment Table on page 1.
Introduction
In this experiment, the I-beam will be supported on two rollers (Fig-
ure 7) with a downward load force applied to the center. You will
use sensors to measure maximum displacement as a function of
applied force. You will repeat the measurement with the beam
turned on its side.
The upright beam is more rigid than the sideways beam; therefore,
the sideways beam will deflect more.
Before proceeding, predict how much more the sideways beam
will deflect (compared to the upright beam) for a given force.
Record your prediction and explain how you made it.
Note: The following instructions assume that you are familiar with setting up
PASPORT sensors and analyzing data in DataStudio software or on the
Xplorer GLX. For more information, see the instructions that came with your
sensors and interface, or press F1 to open DataStudio’s on-line help.
Set-up
1.
Place two pencils on your bench top about 58 cm apart (Figure 7).
2.
Tape down the pencils to prevent them from moving.
3.
Place the I-beam in the upright orientation on the pencils.
4.
Set up one of the following sensor options (motion sensor or rotary motion sen-
sor) to measure vertical deflection at the center of the beam.
Motion Sensor option:
a.
Tape a card to the bottom of the I-beam in the center as shown
in Figure 8; this card will overhand the edge of the bench and
reflect the motion sensor’s ultrasonic pulses.
b.
Mount the motion sensor on a rod stand on the floor under the
card. Aim the sensor at the bottom of the card. The sensor
should be at least 15 cm from the card.
c.
Set the switch on the motion sensor the near-range setting.
d.
Connect the motion sensor to your PASPORT interface.
e.
Record some sample data and ensure that the sensor “sees” the
bottom of the card and not the bottom of the lab bench. When
you push down on the I-beam, the measured position should
change by a few millimeters.
Tape
58 cm
Figure 7: Experiment Set-up
Figure 8: Motion Sensor
Card taped to
beam
Motion
Sensor