- #1

loobloke

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## Homework Statement

A strip of high-strength steel has a length of 30 cm and a cross section of 1 mm by 20 mm. The modulus of elasticity is 200 GPa, and Poission's ratio is 0.25. It is subjected to an axial load of 15,000N. It is instrumented with two axial strain gauges with R=159Ω and a gauge factor of 2.02. These two gauges are connected into opposite legs of a Wheatstone bridge (R1 and R3). The two fixed resistors are also 159Ω, and the supply voltage is 3.4V. The bridge is adjusted to zero-voltage output before the load is applied.

Find the output of the bridge with the load applied.

## Homework Equations

Hooke's Law

Wheatstone Bridge Equation for Strain

## The Attempt at a Solution

I've used the cross sectional area and Hooke's Law to find the strain. From then I just sub it into the wheatstone bridge equation?

However extra information is given so I'm afraid I might be missing something out.

We are applying axial load and measuring axial strain so possion's ratio is irrelevant. Likewise the length of the beam is also irrelevant then. Am I correct in thinking this?

Thanks.