Verifying Stress Components in a Circular Cylinder

[maros522]

The stress components in a circular cylinder of length L and radius r
are given by

sigmaij=[Ay+Bz, Cz, -Cy; Cz, 0, 0; -Cy, 0, 0]

(a) Verify that in the absence of body forces the equilibrium equations
are satisfied.
(b) Show that the stress vector vanishes at all points on the curved
surface of the cylinder.

I have problem with this example, especialy with point b. Do You have some idea?

 

[Mapes]

I've never heard of a "stress vector"; stress is a tensor. Perhaps this is referring to a resolved external force at the surface?

 

[maros522]

In this example the stress vector is defined as t_i=n_j * sigma_ij