METHOD DETERMINING RESIDUAL SERVICE LIFE OF MECHANICAL SYSTEMS UNDER NONDESTRUCTIVE ANALYSIS OF RESPONSE OF ACOUSTIC EMISSION Russian patent published in 2002 - IPC

FIELD: aerospace, mining, oil and gas and construction industries. SUBSTANCE: correct prediction of residual service life of mechanical systems is achieved by analysis of physical and mechanical properties of initial standard metal: σ_S-temporary tensile strength; σ_ys- yield strength; ψ_ra- reduction of area; δ_el elongation; ρ_md- metal density; C*L

-longitudinal sound velocity and C*S- lateral sound velocity. Joint analysis of acoustic emission frequencies is conducted: resonance shear-separation frequency in range f_sh-s= 1600-2500 Hz, relaxation modulation frequencies f_mp and f_mc in range 14-440 Hz, combined by change of friction angle of structural inhomogeneities of natural roughness in intergrain throats of metal ( steel ) ρ^* = 0,5[arctg(ψ_ra/δ_el)+16^°], degrees in range ρ^* = 16^°-50^°, taking into account metal degradation, otherwise, value of cyclic crack resistance K_1c-f.. By that specified change ρ^* up to 45 degrees is identified after fixed operation time T_i, when responses of acoustic emission frequencies f_sh-s, f_mp and f_mc, with characteristic amplitudes of shear-separation stress τ_sh-s, to time of residual life ΔTn are measured. EFFECT: improved correctness of prediction. 3 tbl, 1 tbl