In distortion energy theorem, if a unit cube is subjected to biaxial stress, then S(yt) is given by which of the following?

A)
σ₁²+ σ₁σ₂ +σ₂²
B)
σ₁²- σ₁σ₂ +σ₂²
C)
√ (σ₁²+ σ₁σ₂ +σ₂²)
D)
√ (σ₁²- σ₁σ₂ +σ₂²)

Correct Answer : Option (D) :   √ (σ₁²- σ₁σ₂ +σ₂²)


Explanation : S(yt)=√[(σ₁ -σ₂)²+(σ₂ -σ₃)²+(σ₃ -σ₁)²]/2, for σ₃=0; expression a is obtained.