Question

A strain gauge with a 4 mm gauge length gives a displacement reading of 1.5 um. Calculate the stress at the location of the strain gauge if the material is a) structural steel, and b) PMMA.

Answer 1

1) 75Mpa

2) 1.125 MPa

Step-by-step explanation:

given data:

gauge length = 4 mm

displacement
`= 1.5\mu m = 1.5* 10^(-3) m`

a) structural steel

Young modulus for steel is
`200 GPa = 200* 10^3 MPa`

we know that

`E  =(stress)/(strain)`

`Stress = 200* 10^3 * (1.5* 10^(-3))/(4)`

= 75Mpa

b) PMMA

Young's modulus
`= 3GPa = 3*10^3 MPa`

`stress = 3* (1.5*10^(-3))/(4)`

stress = 1.125 MPa