(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

For a plane stress state, show that the principal stresses and strains occur in the same direction?

2. Relevant equations

Hookes Law for PLane Stress States

Principal Stress is tan(2θ)=2δ/([itex]\sigma[/itex]x-[itex]\sigma[/itex]y)

Principal Strain is tan(2θ)=[itex]\gamma[/itex]xy/([itex]\epsilon[/itex]x-[itex]\epsilon[/itex]y)

\gamma=\tau/G

G=E/(2(1+v))

3. The attempt at a solution

tan(2θ)*([itex]\epsilon[/itex]x-[itex]\epsilon[/itex]y)=tan(2θ)*([itex]\sigma[/itex]x-[itex]\sigma[/itex]y)2(1+v)/2E

I cannot see how to get rid of (1+v)/E, can anyone help me out please.

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# Homework Help: Princiap Stress and Strains

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