Question

Help with part B, please!

I have worked part a (answer below) and drew Mohr's circle, but I simply do not understand "b" at all. I know what hydrostatic pressure is but I just do not understand what is asking or even how to implement. Thanks!

Problem:

A stress element in plane stress encounters $\sigma$_x = 20 MPa, $\sigma$_y = -10 MPa, and $\tau$_xy = 13 MPa.

(a) Determine the three principal stresses and maximum shear stress.
( My answer: $\sigma$₁= 24.8 MPa,  $\sigma$2= 0,  $\sigma$3= -14.8 MPa,  $\tau$_1/3= 19.8 Mpa, $\tau$_2/1= 12.4 Mpa, $\tau$2_/3= 7.42Mpa)

(b) Using a Mohr’s circle diagram, explain the effect of superimposing a hydrostatic pressure p on the principal stresses and maximum shear stress.

Answer 1