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## Homework Statement

A sample is put in tension and a strain rosette gives the following results:

i) Calculate principal strains and poissons ratio using Mohrs strain circle.

ii) Calculate principal stresses from principal strains and poissons ratio.

## Homework Equations

Mohr's strain circle

γ = -lateral strain / axial strain

σx = E / 1 - γ

^{2}(εx + γεy)

σy = E / 1 - γ

^{2}(εy + γεx)

E = 210 GPa

## The Attempt at a Solution

I have drawn up Mohr's circle in autocad and found the following results.

principal strains = 122.5x10

^{-6}& -296.5x10

^{-6}

poissons ratio = -122.5 / -296.5 = 0.413 (this seems too high?)

principal stresses = σx = 11.5kPa (this is supposed to be low as the load is applied in the y direction?)

σy = -62.99MPa (should this be negative if its in tension?)

Im hoping someone can tell me if im on the right track.

Thanks in advance!