Principle stress states question, anyone help?

[scw1]

Principle stress states question, anyone help??

Homework Statement

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?

Homework Equations

Plane stress and strane equations

The Attempt at a Solution

Got an answer of an answer near to 212MPa and 83MPa
but not sure if its right

 

[nvn]

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

 

[scw1]

Your current answer looks incorrect. Try again.

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

 

[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.

 

[DeeNos]

The principle stress states question refers to the calculation of the two principle stresses (sigma 1 and sigma 2) based on the given principal strains obtained from neutron diffraction. It appears that the person asking for help has attempted to solve the problem and has come up with an answer, but is unsure if it is correct.

To verify the solution, the person could compare their answer to the equations for plane stress and strain, which relate the principle stresses and strains to the Young's modulus and Poisson's ratio. They could also double check their calculations and make sure they are using the correct units. If there are still doubts, they could seek assistance from a colleague or a teacher.