Strength of Materials

3.5 STRAIN ENERGY IN TERMS OF PRINCIPAL STRESSES

Let the major and minor principal stresses in a strained material be σ₁ and σ₂ and of the same sign. Then, the principal strains are given as

 

 

Strain energy per unit volume due to σ₁,

 

 

Total strain energy per unit volume U = U₁ + U₂

 

 

In the case of 3D principal stress (with same sign) condition, ...