MAE244 – Lab 1 Prelab Quiz NAME: GROUP #: ID. # s

ELECTRICAL RESISTANCE STRAIN GAGES - APPLICATION TO BEAM

BENDING

1. Strain is a measure of ___________________ and its units are _______________.

2. ______________ are used to directly measure the change in gage length.

3. What is the principle of operation of the electrical resistance strain gage?

4. The strain gage is a straight length of wire. [True, False]

5. Strain gages measure only normal component of strain. [True, False]

6. The resistance of a strain gage mounted on a structure was measured to be 120 ohms with no load. After loading, the resistance changed to 122 ohms.Assuming gage factor Sg = 2.10, what is the strain?

7. For the Wheatstone bridge shown in the figure, determine the strain measured by gage R1 if voltage drop E is measured to be 0.0050 volts.(gage factor Sg = 2.12, and R1 = R2 = R3 = R4 at zero load.)

8. For a cantilever beam of 10" long with a load at the free end, calculate the theoretical strain at 7" from the free end when the deflection at loading point is 0.3" (Assume a beam thickness of 0.1").

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