Strain Gage Mounting & Strain Measurement

Measurement & Instrumentation Laboratory

Strain Gage Mounting & Strain Measurement

Short report format is required for this exercise.

Objective:   After completing this laboratory exercise you should be able to properly mount a strain gage and use it for measurement of strain.

Strain Gage Mounting

1. Follow the strain gage mounting instructions from Student Manual for Strain Gage Technology by Measurements Group with the following additions:

          Layout lines are to be centered side-to-side on the beam and 9 inches from the load point (center-punch mark).

          The gage is to be oriented with the solder tabs towards the long end of the beam.

          Use M-Bond 200 adhesive.

          Lead wires are to be approximately two feet long. Join the black and white wires together at the strain gage.

2. Check resistance from gage to specimen (this should be an open circuit). Measure and record your actual gage resistance (this should be reasonably close to the nominal value specified by the gage manufacturer).

3. Record your name and the gage factor on your beam.

Strain Measurement

4. Clamp your beam as a cantilever to the wooden workbench in the backroom. Keep the clamp and bench ½ inch or more from the gage.

5. Review the user manual provided with the strain indicator and then follow the instructions to properly setup the strain indicator.   These are briefly summarized as follows:
                1) Connect gage and select the proper bridge setting (your single active gage will be a quarter bridge).
      2) Zero the amplifier.
      3) Set the gage factor.
4) Zero the output with no load.

Sketch your entire setup (beam mounting and electrical connections).

6. Load your beam with 10 pounds and record the measured strain.

7. Estimate the uncertainty (in microstrain) of your strain measurement.

8. Using the properties of the beam and the applied load, calculate the value of strain...