Pisarenko-Lebedev criterion for homogeneous materials

For Pisarenko-Lebedev criterion for homogeneous materials, analysis is performed according to the following formula:

σ_{Pisarenko-Lebedev;HO} = X⋅ σ_i + (1 - X) ⋅ σ₁

X = σ_u,t / σ_e,c

Where:

σ_{Pisarenko-Lebedev;HO}  – Pisarenko-Lebedev criterion for homogeneous materials;

σ_i  – intensity of stress;

σ₁  – principal stress;

σ_e,c  – ultimate compression;

σ_u,t  – ultimate tension.