This document provides instructions for conducting an experiment to measure strain on a cantilever beam using a rosette strain gauge and strain indicator. The instructions include measuring the beam's dimensions, calculating the required load, connecting the strain gauges and indicator, taking initial readings from each gauge, applying the load and recording strain readings, and measuring the gauge orientations.

1. 1. Measure the distance from the center line of the rosette to the
loading point on the free end of the beam (L).
2. Measure the width (b) and thickness (t) of the beam with a
micrometer.
3. Using the cantilever beam flexure formulae , calculate the
load P, to be applied at the free end of the beam for a stress
value of σ = 15000 psi.
4. Back the calibrated loading screw and insert the beam into
the Flexor with the gaged end in the clamp, and with the gage
on the top surface.
5. Connect the lead wires from the rosette to the binding posts
of the flexor as per the wiring diagram given in the handout. Be
careful when handling the wires.
6. Connect one of the common leads from the flexor (#1) to the
S- binding post of the strain indicator.
7. Connect the other common lead from the flexor (#2) to the D-
120 binding post of the strain indicator.
8. Connect the independent lead from Gage Element 1 (#3) to
the P+ binding post of the strain indicator.
9. After balancing the strain indicator amplifier, set the gage
factor to the value given on the strain gauge.
10. With the beam unloaded set the instrument to RUN.
11. Adjust the balance control of the strain indicator until the
digital readout indicates precisely zero (there may be some
fluctuation; if so, note the average reading). Do not adjust the
balance control again during the experiment.
12. The initial reading for the strain Gage Element 1 should
now be recorded on the worksheet as 0με (or the averaged
reading from the step above).
13. Turn the strain indicator off, and disconnect the independent
Gage Element 1 (#3) lead from the P+ binding post; leave the
common leads connected.
14. Now, connect the cable lead from Gage Element 2 (#4) to
the P+ binding post and then turn the instrument on.

2. 15. Without adjusting the balance controls, note the reading on
the indicator display.
16. This is the initial reading for Gage 2, and should be
recorded on the worksheet.
17. Turn the strain indicator off, and disconnect the independent
Gage Element 2 (#4) lead from the P+ binding post, leaving the
common leads connected.
18. Connect the cable lead from Gage Element 3 (#5) to the P+
binding post and turn the instrument on.
19. Without adjusting the balance controls, note the reading on
the indicator display.
20. This is the initial reading for Gage 3, and should be
recorded on the worksheet.
21. After recording the initial reading for Gage Element 3, leave
the gage connected and apply the previously calculated load ‘P’;
Hang the weights on the free end of the beam.
22. Record the exact weight ‘P’ on the work sheet and record
the indicated strain for Gage Element 3 in the table.
23. With the load on the beam, turn the strain indicator off and
remove the Gage Element 3 (#5) and replace it with the Gage
Element 2 (#4) to the P+ binding post.
24. Turn the strain indicator on and record the indicated strain
for Gage Element 2 in the table.
25. With the load on the beam, turn off the strain indicator and
remove the Gage Element 2 (#4) and replace it with Gage
Element 1 (#3) to the P+ binding post.
26. Turn the strain indicator on and record the indicated strain
for Gage Element 1 in the table.
27. With the last gage still connected to the instrument, remove
the load from the beam. The strain indicator readout should now
indicate the same (within a few με) as the initial reading for this
gage.
28. Finally, use a protractor to measure the counterclockwise
angles between Gage 1 axis and lateral and longitudinal beam
axes.