Problem 10-85

Yield stress of the material is

s_Y = 934 MPa

a) By maximum shear stress criterion,

t_max = (s_max - s_min)/2 = (s₁ - 0)/2 = s₁/2

Yield start at t_max = s_Y/2, thus at

s₁ = s_Y = 924 MPa

b) By the distortion energy criterion

Yield starts when

s₁² - s₁s₂ + s₂² = s_Y²

or

s₁²(1 - 0.5 + 0.25) = (924)²

s₁ = 924/sqrt(0.75) = 1066.9 MPa