For Balandin criterion, analysis is performed according to the following formula:
σBalandin = 3 * (1 - X) * σA + L * σi**2
σA = 1/2 ⋅ (σ1 + σ2)
X = σu,t / σe,c
L = 1 / σe,c
Where:
σBalandin – Balandin stress criterion;
σi – intensity of stress;
σA – average stress (hydrostatic pressure);
σ1, σ2 – principal stresses, σ1 ≥ σ2;
σe,c – ultimate compression;
σu,t – ultimate tension.