I asked this question 2 times.
Please solve index notation.
Components of the stress tensor σ at a point, with respect to the (x,y,z) coordinate system, are given as
σ = 18 24 0
24 32 0
0 0 -20 (MPa).
a) Find the principal stresses σ and the unit vectors ei along the principal directions. Arrange σi such that σ1 > σ2 > σ3. Further, choose the senses of e such that e1 · e2 · e3 = +1.
b) Find the hydrostatic and deviatoric parts of σ.
c) Find the maximum shear stress σs max and the normal to the planes on which σs max acts. Express the normal in terms of the unit vectors i, j, k.