For Pisarenko-Lebedev criterion for heterogeneous materials, analysis is performed according to the following formula:
σA = 1/2 ⋅ (σ1 + σ2)
X = σu,t / σe,c
L = 0.7 (by default)
Where:
σPisarenko-Lebedev;HE – Pisarenko-Lebedev criterion for heterogeneous materials;
σi – intensity of stress;
σA – average stress (hydrostatic pressure);
σ1 – principal stress;
σe,c – ultimate compression;
σu,t – ultimate tension.