# Principle stress states question, anyone help?

1. Sep 15, 2010

### scw1

Principle stress states question, anyone help??

1. The problem statement, all variables and given/known data
Neutron diffraction is used to measure the residual strains near to a weld in an aluminium plate. The aluminium has a young’s modulus E of 70GPa and a poisons ratio of 0.3. The three principal strains obtained are ε1= 2400 με ε2=0με ε3=-350με. What are the values of sigma 1 and sigma 2???

2. Relevant equations

Plane stress and strane equations

3. The attempt at a solution
Got an answer of an answer near to 212MPa and 83MPa
but not sure if its right

2. Sep 15, 2010

### nvn

[strike]Your current answer looks incorrect. Try again.[/strike]

Last edited: Sep 16, 2010
3. Sep 16, 2010

### scw1

Re: Principle stress states question, anyone help??

Hi there the sigma2 must be 83MPa???? its all i keep getting
Many thanks
Stevo

4. Sep 16, 2010

### nvn

My apologies, scw1. Your answer was right. Nice work. However, generally always round your final answer to three significant digits, not two significant digits. You rounded slightly too much. Also, you misspelled principal and strain, and omitted all punctuation.