Question

According to maximum normal stress theory, the maximum normal stress in the shaft is

Answer 1

Maximum normal stress theory, introduced by Rankine, ignore possibility of yielding undershear. That means your can only apply Rankine's theory to material which very strong in shear. According to strength of materials brittle one are strong in shear, weak in tension or compression.

Answer 2

Question

According to maximum normal stress theory, the maximum normal stress in the shaft is

Answer

We know that shear stress on an oblique plane at an angle θ to the cross-section of a body which is subjected to a direct tensile stress σ is equal to

2

σ

sin2θ. Thus maximum value of this occurs at θ=45

o

which is

2

σ