Suppose you work in a lab to develop a robotic fish that can swim at various depths of the ocean. A part of the robotic fish can be considered as a metal block that is exposed to the compressive pressure p that the water exerts on all sides of the block. Besides the compressive pressure p, the only other stress that the metal block is subject to is a shear stress loading Txy. Hence, the other two shear stresses are zero ( Txz = Tyz = 0). The yield strength of this metal is 0. = 300 MPa.

(a) Suppose the robotic fish swims in a depth of the ocean where the water pressure loading is p= 90 MPa. Use the Octahedral Shear Stress Yield Criterion (i. e. the von Mises Yield Criterion) to determine the largest value of Txy that can be apply if we want a safety factor against yielding of X.= 1.5?
(b) Suppose the robotic fish then swims in a depth where the water pressure loading is 20 times more, i. e. p = 1,800 MPa. Use the Octahedral Shear Stress Yield Criterion (i. e. the von Mises Yield Criterion) to determine the largest value of Txy that can be apply if we want a safety factor against yielding of Xo = 1.5 ?